I want to thank you for all your hard work . I own a HF model I bought it in Feb 2015 , shortly after I became bed bound and still am. It's still in its crate in my shop , it's all I could afford with your extras ill be very happy . After many drs and pain drs surgeons , now one is giving e hope I'll get my shop before I die. I've got a big 20" drill press power feed . A old Rockwell 7v saw and a power hacksaw, even a landis surface grinder, a used enco mini Bridgeport mill. Welders plasma cutter grinders . I'm set , I'm a wheelchair till I go to I think . But you inspired me to go to town on my rc mill drill. Thank you very much you should be as popular as tho other stuck up youtubers , God bless you. Silverbullet
Nice to see those mods Joe, you've done some fine work - did see one or two previously but, good to see all that stuff together. Would love to go the VFD route.... high torque is good! Nice demo.
you have done a fantastic Joe.....and lets face it....anyone can buy a bridgeport mill but not everyone can do what you do...Thanks for showing i enjoyed!
You have basically the same mill I got from Grizzly. Nice improvements. I wish I had dragged up the extra money and got a gear head and "V" column. Still like you said it does the work, just takes some extra time moving belts and re-centering on parts now and then. I have some vibration at about 1500 rpm that makes me afraid to run it any faster. Thanks for sharing.
Your videos are immensely helpful. When you produced this video I had a Bridgeport clone and a good Jet lathe that I sold when I moved 700 miles. In 2023 I opted to buy an old Jet-26 over a new Chinese square column mill, not fully understanding the issues with the round column. My Super Spacer would have been a big load on a Chinese mill. Not sorry I bought it and the first thing I did on it was for someone else. Can't say it was for profit because I spent as much or more time getting the mill to work smoothly as I did making the pieces. The power is good and the accuracy also seems adequate as long as I can do everything without moving the head. Your Thompson bar mod is in the forefront of my planned mods. Electric lift would be nice, too. Mine has 2 idler pulleys and 3 belts (very early version?) so the 3 phase/VFD is also a nice option. DRO is more important than some of the other mods, though. My new shop is much smaller than the last one so the size of the round column mill is appealing. A full sized floor model would eat up a lot more space. Thanks for your contributions!
Hey Joe, just wanted to post a big thank you for taking the time to post your Rong Fu mods. I've got a ZX25, which is (I believe) an RF25... So it's essentially the Wrong Fu's little brother. :) I've just got some 25mm linear rail, and a bearing block - and along with some inch thick aluminium bar stock I shall be shamelessly copying your guide rail. I'm thinking of placing my rail on the opposite side of the head though - and bolting the bearing block directly to the head casting. That should still give me access to the column lock bolts and belt tensioner - the only thing that gives me pause on that is getting the bearing mounted on the less than flat & true surface... Oh and the captive draw bar? Genius. :D Cheers, Jason
+Jason Cundall Thanks Jason, I am glad that you got some ideas for your mill. One thing to remember about the rail is the farther away you can get it from the column, the better. Think about leverage on the bar. The fulcrum is the column and the force is applied over the distance from the spindle to the column. In order to minimize the bending force on the linear rail, you want to get it as far from the column as you can.
Hi joe. Thanks for the video. My skills are limited, but I'm mostly interested in your articulating work light. Can you tell what it consists of besides the coolant line ?
Thanks for the video.. I just got the same machine and have some plans and questions on it I'd like to share soon. If I were to post a vid.... I'll let you know when it's up... Could you take a look and comment?
It looks like you have little to no backlash on the z axis fine adjustment. Did it come like that or did you figure out a way to take out the backlash.
Joe, I have the same bench mill you have and I am having problems getting the collets to totally engage to the threaded end of the draw bar. Is there a collet guide or adjustment I can make or replace.
Hey Joe we’re have you been? Your last video was about a year ago . Hope all is fine . I enjoy watching them. I need your help though. Do you have the part number for the Torrington bearing that you used on your draw bar? I am working on changing over my drill/ mill and have not been able to find that one. Thanks so much.
Hi Cuppa Joe, I thank you for this video, it's very instructive! I have some questions for you : - can you tell me what is the exact product number of your vfd? Is the vfd powered by 120V or 240V? I have a RF30 clone and I'm looking too to convert it to variable speed. What are the main characteristics that I have to look for on a vfd? I plan to use a 3 phases AC motor. I thank you. Steph
My VFD is a Mitsubishi FR-D720S-100 single phase 240 volt input, 3 HP drive. The motor is a WEG 00218ET3FVD145TC, 2 HP vector duty rated motor. The key things are to over rate the drive, (3 HP for a 2HP motor) Also try to get a motor that is rated for inverter duty, they have special windings to handle the higher frequency. In order to get the best performance, you must match the motor to the drive. There are motor parameters (winding resistance and inductance R1, R2, X1, X2, XM) that if matched properly will allow the drive to operate the motor with the highest performance. It is quite involved but the motor tech support people should be able to guide you.
Hey Cuppa thanks for all these videos on the wrong foo! I am currently rebuilding a Rong foo RF-31 and i got 2 major questions; 1) Can i use the original motor with a VFD? (I can wire my motor to 220v but it comes pre-wired at 110v) 2) can you make a video explaining how to make the quick collet removal insert thing? to be honest I'm not really sure how to remove the collet without your jig so if you could explain that also it would be awesome! thanks
You need a 3 phase motor to run a VFD. The original motor wont work in that application. If you look through my old video's you will find one on how to make the captured draw bar. It should be in a subsequent Doodads IIRC.
When I retired, I decided to try my hand at machining. I am in the process of buying an old Grizzly G1006. Found your site while browsing around YT. Very good information. Thank you. One question I have is about the motor you used to replace the original. Do you have a part number or source for It? I am electrically challenged, especially when people start talking about VFD's. This old dog has a lot to learn.
That motor was a WEG 3 phase 2 Horse power. They dont make that particular motor any more but this link will take you to the page about VFD rated motors. www.weg.net/us/Products-Services/Electric-Motors/System-Drive-VFD-AC-Motors/System-Drive-VFD-AC-Motors One thing you have to remember about VFD's is that if you are converting single phase to 3 phase, you should oversize the inverter. I have a 2HP inverter duty 3 phase motor but it is being driven by a 3 HP VFD.
Please excuse my ignorance but I always thought that an AC motor could not be variable speed. It was my understanding that a DC motor was required. The reading I have been doing keeps talking about AC VFD controls. I am getting too old to be doing all this thinking. It hurts. And I haven't even begun to try to get my head around Arduino controls. I can't even program my cell phone.
No problem Jack, The speed of an induction motor is directly proportional to the frequency of the AC and the number of poles. So by varying the frequency, the speed can be controlled. What a VFD does is create it's own AC voltage waveform to drive the motor. The frequency of this waveform can vary anywher from zero (braking) to 240 Hz (some go higher) Which will allow a very high top speed if desired. The reason for a 3 phase motor is that it will be bidirectional. You can do it with a single phase motor but it is more complex. The 3 phase motor option is the best and simplest. A typical VFD will have accel and decel control as well as motor protection.
Question: The length of overhang from the edge of the column to the linear rail is a long way, looks like about 200mm aprox. I would have thought the close to the column, the better it would be....less moment arm.....more ridged.....I've been measuring up mine a think I can get it 75-80 from the column edge between the from belt and clear of the idler arm......should be better? My RF30 is an oddity it has a 900mm column and as NEVER been to the end of it length. going to use 25mm rail for the retro fit. Thanks for the video. T
Think of it this way Trevor, you want the linear rail to keep the head from rotating on the column, the distance from the column to the quill is a fixed lever arm. You want the distance from the column to the rail to be as large as possible to provide a long lever as well. If the distance from the column to the rail is short, it will be more likely that the rail will flex. The rail will always have a certain amount of flex, the larger the distance of the rail to the column, the lesser the head will rotate due to this flex. J
Hey Joe when you went to a single belt setup what did you do for your pulley adjustment? I noticed after changing mine that there isn't a very good way to adjust the belt with the factory geometry.
On my mill, the motor moves on a pivot. I just picked the right belt size so it would tighten up when I moved the motor back. There is a thumbscrew on the right side of the head near the back that acts like a grub screw to lock a spring plunger.
Stock weight for the Enco RF-30 is 300 KG, times 2.2 is 660 pounds. Table/stand weighs 200 to 300 pounds, usually. that vise weighs an extra 100 pounds... My RF-30 has the Z Axis power feed, which is another 10 KG. (22 pounds) which makes it an RF-31... All the clones are similar in weight. If you go and verify it, you will find the exact same typo errors, and Engrish descriptions, with the words SOLT for SLOT for an example, in the manuals, that have the exact same date stamp of 1996 on the covers, for the JET and Central Machinery Mills... HFT number is #33686 for the 12 speed unit that is identical copy of the Enco RF-30.
You have added some serious value to that round column mill!!!! Your linear bearing add-on looks like the best mod to get accuracy when raising or lowering the head...... how accurate is it?
+lornie212 It is very accurate as long as you don't push on it. That 1" rail is very rigid but if you loosen the head and push pretty hard, it moves about .001" just raising and lowering though, the movement is negligible.
Whatever your display is showing, it is not the frequency! 'Slip' in an induction motor would never reach over 50% without load. Slip at maximum load is normally around 4%. Much more than that and torque would drop and the motor freeze. I have four VFD systems, and they all give frequencies that match the RPM. It may be giving you the servo loop value- hard to say without more information.
If memory serves me, it was either 1/2-13 or 7/16-20, the hole in mine was close to the tap size for one of these so I just ran a tap in then make the collar to match.
Oh, OK, I did not know you were talking metric. I tapped mine imperial. But whatever works I guess. If you have a lathe, make a tapping fixture. One ID fits over the splines on the quill and another ID to keep the tap in line. That way you can do it on the machine without removing the spindle.
+Cuppa Joe I basically just wondered if you had to drill the spindle out at all for a tap. M14 x 1.25 is pretty much spot on for the existing hole and its a pretty common tap as its spark plug size. Good advice about the tap guide, I will do that, thanks again
I don't get what you were saying about the vfd, when you added the load and you said the vfd compensates to keep the motor at 21 rpm, the spindle speed jumped way up...so it's not really keeping a steady rpm...
It is trying but the only feedback the vfd has is from the back emf of the motor. Not true closed loop performance like if you had an encoder or a tachometer on the motor. There is an inherant the delay in this type of system an thus the motor temporarily speeds up before stabilizing.
Joe, instead of the rod to eliminate the rotation of the head when it's raised and lowered, wouldn't it be easier to mount an indicator to the cast lower column and angle the arm of the holder axis to be non parallel to the column which would hold an indicator set to measure the rotation of the head during the raising and lowering of the head? I know that's a long sentence. Hope you can understand what I mean. If you knew the deflection, wouldn't it be fairly easy to tap the head back to a zero reading?
Hello again Joe, would fixing the jack (my best guess on the name based on parts diagram) to the post reduce the rotation of the head? Any problems that you can see? I can't see a need for head rotation anyway. I hope the move is going better. What a nightmare.
Not really Bill, there is too much slop in the jacking mechanism. I tried fixing my elevation rack to the column a while ago and the head still moved way too much.
I'm 90% complete your draw bar mod for a grizzly knee mill but am having trouble identifying the torrington bearing you used....your assistance would be appreciated.
Victor Wheeler Victor, the cage assy. is a NTA-613 and the washers are TRB-613 but you can use anything that will fit your specific application, it's not critical.
Why not ditch the bearings for the X and Y which are terrible and put on better ones. The chinese ball screw bearing fit mine just fine. The modify the original acme I just threaded it 17 mm, bought a couple of nuts and was good to go. Lost a whole lot of slop. The reinforcing plates on the back of the column are a great idea. Currently am replacing the spindle drive bearing and the quill bearing using 2RS bearing to get rid of the need to grease. A problem with these machines is the quill holder rocks in the column. One thread got rid of that rocking by usings a car air spring, I am using a air cylinder as there is enough room in the front if one removes the rod which gives the depth when you put the electronic readout on the outside of the cover. If you have the spindle bearing out you can easily remove the entire sheet metal pan and the cylinder would fit to the back in the holes behind the quill holder. One reason to use the front is if something fails, it is much easier to remove and replace as you do not need to take the sheet metal safety pan off.
Thanks for the videos, Joe! I've watched each a couple times (going through them again now that I have my inherited RF-30 type round column mill). Here's what baffles me about the round column mills: why do they exist? My assumption is that the ground round column is significantly cheaper to manufacture than a dovetail column or knee. But is there also some other function to having it? I guess by rotating the head a bit you could theoretically mill a bit further down the table, then rotate the other way, re-align, and do it again on the other side to get a little bit larger work envelope in the one direction (at the expense of the other), but that is quite impractical. Obviously it wouldn't be any more work to move and re-indicate the workpiece. So is there some obscure function to the round column and rotating head that I don't see? Something you happily sacrificed by doing the linear rail mod?
Hi Jon, I think it is combination of cost and a perceived notion of increased functionality in that you can drill off table. Back when I got mine, they didn't have square column mills, my philosophy is if you dont like something, modify it!
That was fast! Glad to know I'm not just "not getting it". I spent six weeks building a new workbench (as I had time) to hold my lathe, this mill, and a surface grinder. Finished it two weeks ago, and got the mill moved here last weekend. Today I finally get to fire it up after wanting one for years and knowing it was coming for months. Eventually, after I finish making the drawers for the bench and getting things organized, I will have to do some of these mods. Thanks again!
One place where the round column is helpful is that you can let work hang off the back side of the table and you can swing the head around to get to it. A job where you might use this is repairing an axle that has a damaged hole for a wheel stud. You would swing the head around on a Bridgeport knee mill to do this job as well.
I've got the Grizzly version of the same machine. There is " slop " between the spline of the spindle and the spline-broached alum step pulley which drives the spindle. This means if you hold the spindle, you can very slightly rotate the pulley. This " slop " causes a problem with surface finish. I smeared heavy greaser on the spline which helped somewhat but didn't eliminate the problem. Any ideas ?
Noise is an indication that something is wearing, and that noise is going to get louder as the mating parts increasingly wear. Surface finish will be improved if this problem is corrected. One solution would be to put a "drag" on the alum spindle-drive pulley. Another would be several set-screws thru the drive pulley jamming a piece of teflon or other suitable polymer directly onto the spindle-spline. The polymer, especially teflon would deform under the pressure of the set-screw and fill the "slop" between the splines, while still allowing the spindle to move vertically. Your thoughts....
Hey Joe - I've completed my WrongFu inspired mods, and couldn't be happier the way they turned out: www.hobby-machinist.com/threads/tips-for-owners-of-rong-fu-rf-20-rf-25-rf-30-rf-31-mill-drills.38796/#post-375850 Thanks again for sharing.
+Jason Cundall Wow Jason, That is awesome! Thanks for the link to the forum. I will be lurking there. I had no idea there were people talking about those mods, I am shocked. Your machine turned out great. I like the way you designed your brackets to hold the rail.
+Cuppa Joe thanks Joe! :) The best thing about the arms is because they're quite thick, they almost self align. I haven't really knocked it about yet to try and get it dead true, but it's clocking at under a thou (0.02mm - I'm a metric man) over the length of the quill. I'm sure if I took an hour our so of loosening various brackets and methodically going through the them all as there's hardly any flex. It sure does help with stiffening up the column as well. :)
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I want to thank you for all your hard work . I own a HF model I bought it in Feb 2015 , shortly after I became bed bound and still am. It's still in its crate in my shop , it's all I could afford with your extras ill be very happy . After many drs and pain drs surgeons , now one is giving e hope I'll get my shop before I die. I've got a big 20" drill press power feed . A old Rockwell 7v saw and a power hacksaw, even a landis surface grinder, a used enco mini Bridgeport mill. Welders plasma cutter grinders . I'm set , I'm a wheelchair till I go to I think . But you inspired me to go to town on my rc mill drill. Thank you very much you should be as popular as tho other stuck up youtubers , God bless you. Silverbullet
Hell yeah man, my shop has cost me pain and tears but wort every bit of it
Hey Joe thanks for restarting my faith in round column mills great mods excellent video
Nice to see those mods Joe, you've done some fine work - did see one or two previously but, good to see all that stuff together. Would love to go the VFD route.... high torque is good! Nice demo.
Nice Mods on the Mill, I’m thinking of doing a lot of the same Mods to mine. You did some great work.
you have done a fantastic Joe.....and lets face it....anyone can buy a bridgeport mill but not everyone can do what you do...Thanks for showing i enjoyed!
+Lawrence Harasim Thanks for the kind words Lawrence, glad you enjoyed it.
You have basically the same mill I got from Grizzly. Nice improvements. I wish I had dragged up the extra money and got a gear head and "V" column. Still like you said it does the work, just takes some extra time moving belts and re-centering on parts now and then. I have some vibration at about 1500 rpm that makes me afraid to run it any faster. Thanks for sharing.
Your videos are immensely helpful. When you produced this video I had a Bridgeport clone and a good Jet lathe that I sold when I moved 700 miles. In 2023 I opted to buy an old Jet-26 over a new Chinese square column mill, not fully understanding the issues with the round column. My Super Spacer would have been a big load on a Chinese mill. Not sorry I bought it and the first thing I did on it was for someone else. Can't say it was for profit because I spent as much or more time getting the mill to work smoothly as I did making the pieces. The power is good and the accuracy also seems adequate as long as I can do everything without moving the head. Your Thompson bar mod is in the forefront of my planned mods. Electric lift would be nice, too. Mine has 2 idler pulleys and 3 belts (very early version?) so the 3 phase/VFD is also a nice option. DRO is more important than some of the other mods, though. My new shop is much smaller than the last one so the size of the round column mill is appealing. A full sized floor model would eat up a lot more space. Thanks for your contributions!
This man is a very clever individual these are the kind of people you learn a lot from keep up the good work cuppa joe
Thanks, that means a lot to me.
do you have any drawings of the drawbar that looks excellent setup,
lots of great mods here, thanks for sharing
+Brian Stanga Like they say, Chinese machinery is like a parts kit. You get to customize it to make it work!
@@ReignOterror what vice is that?
Joe,
I have a RF-30 that I want to use your drawbar modification on. Wish me luck!
Hey Joe, just wanted to post a big thank you for taking the time to post your Rong Fu mods. I've got a ZX25, which is (I believe) an RF25... So it's essentially the Wrong Fu's little brother. :)
I've just got some 25mm linear rail, and a bearing block - and along with some inch thick aluminium bar stock I shall be shamelessly copying your guide rail.
I'm thinking of placing my rail on the opposite side of the head though - and bolting the bearing block directly to the head casting. That should still give me access to the column lock bolts and belt tensioner - the only thing that gives me pause on that is getting the bearing mounted on the less than flat & true surface...
Oh and the captive draw bar? Genius. :D
Cheers,
Jason
+Jason Cundall Thanks Jason, I am glad that you got some ideas for your mill. One thing to remember about the rail is the farther away you can get it from the column, the better. Think about leverage on the bar. The fulcrum is the column and the force is applied over the distance from the spindle to the column. In order to minimize the bending force on the linear rail, you want to get it as far from the column as you can.
Hi joe. Thanks for the video. My skills are limited, but I'm mostly interested in your articulating work light. Can you tell what it consists of besides the coolant line ?
Nice, clean install. Thanks for the vid.
Thanks Bill, glad you enjoyed it!
Cuppa Joe, i just picked up a rf-30 last week and the motor on it is bad. i am wondering what motor and vfd you are used.
Jimmy S It's a 2 hp WEG 3ph and a 3 hp Mitsubishi D700 drive.
Thanks for the video.. I just got the same machine and have some plans and questions on it I'd like to share soon. If I were to post a vid.... I'll let you know when it's up... Could you take a look and comment?
Nice setup what's the model number for your variavble frequency drive it looks like a FR-D720S-100-EC can't say for sure
It looks like you have little to no backlash on the z axis fine adjustment. Did it come like that or did you figure out a way to take out the backlash.
Joe, I have the same bench mill you have and I am having problems getting the collets to totally engage to the threaded end of the draw bar. Is there a collet guide or adjustment I can make or replace.
Joe where ya been? Miss your content! You sound like your from around my area!
Hey Joe we’re have you been? Your last video was about a year ago . Hope all is fine . I enjoy watching them. I need your help though. Do you have the part number for the Torrington bearing that you used on your draw bar? I am working on changing over my drill/ mill and have not been able to find that one. Thanks so much.
could you tell the model and makes of your motor and vfd Thanx
Hi Cuppa Joe,
I thank you for this video, it's very instructive! I have some questions for you :
- can you tell me what is the exact product number of your vfd? Is the vfd powered by 120V or 240V? I have a RF30 clone and I'm looking too to convert it to variable speed. What are the main characteristics that I have to look for on a vfd? I plan to use a 3 phases AC motor.
I thank you.
Steph
My VFD is a Mitsubishi FR-D720S-100 single phase 240 volt input, 3 HP drive. The motor is a WEG 00218ET3FVD145TC, 2 HP vector duty rated motor. The key things are to over rate the drive, (3 HP for a 2HP motor) Also try to get a motor that is rated for inverter duty, they have special windings to handle the higher frequency. In order to get the best performance, you must match the motor to the drive. There are motor parameters (winding resistance and inductance R1, R2, X1, X2, XM) that if matched properly will allow the drive to operate the motor with the highest performance. It is quite involved but the motor tech support people should be able to guide you.
That was great, I picked up an Acra RF-40 and I need handwheels, I cant find anything besides the plastic junk, do you remember where you found those?
Hey Cuppa thanks for all these videos on the wrong foo! I am currently rebuilding a Rong foo RF-31 and i got 2 major questions;
1) Can i use the original motor with a VFD? (I can wire my motor to 220v but it comes pre-wired at 110v)
2) can you make a video explaining how to make the quick collet removal insert thing? to be honest I'm not really sure how to remove the collet without your jig so if you could explain that also it would be awesome!
thanks
You need a 3 phase motor to run a VFD. The original motor wont work in that application. If you look through my old video's you will find one on how to make the captured draw bar. It should be in a subsequent Doodads IIRC.
When I retired, I decided to try my hand at machining. I am in the process of buying an old Grizzly G1006. Found your site while browsing around YT. Very good information. Thank you. One question I have is about the motor you used to replace the original. Do you have a part number or source for It? I am electrically challenged, especially when people start talking about VFD's. This old dog has a lot to learn.
That motor was a WEG 3 phase 2 Horse power. They dont make that particular motor any more but this link will take you to the page about VFD rated motors. www.weg.net/us/Products-Services/Electric-Motors/System-Drive-VFD-AC-Motors/System-Drive-VFD-AC-Motors
One thing you have to remember about VFD's is that if you are converting single phase to 3 phase, you should oversize the inverter. I have a 2HP inverter duty 3 phase motor but it is being driven by a 3 HP VFD.
Please excuse my ignorance but I always thought that an AC motor could not be variable speed. It was my understanding that a DC motor was required. The reading I have been doing keeps talking about AC VFD controls. I am getting too old to be doing all this thinking. It hurts.
And I haven't even begun to try to get my head around Arduino controls. I can't even program my cell phone.
No problem Jack, The speed of an induction motor is directly proportional to the frequency of the AC and the number of poles. So by varying the frequency, the speed can be controlled.
What a VFD does is create it's own AC voltage waveform to drive the motor. The frequency of this waveform can vary anywher from zero (braking) to 240 Hz (some go higher) Which will allow a very high top speed if desired.
The reason for a 3 phase motor is that it will be bidirectional. You can do it with a single phase motor but it is more complex. The 3 phase motor option is the best and simplest.
A typical VFD will have accel and decel control as well as motor protection.
Question: The length of overhang from the edge of the column to the linear rail is a long way, looks like about 200mm aprox. I would have thought the close to the column, the better it would be....less moment arm.....more ridged.....I've been measuring up mine a think I can get it 75-80 from the column edge between the from belt and clear of the idler arm......should be better? My RF30 is an oddity it has a 900mm column and as NEVER been to the end of it length. going to use 25mm rail for the retro fit. Thanks for the video. T
Think of it this way Trevor, you want the linear rail to keep the head from rotating on the column, the distance from the column to the quill is a fixed lever arm. You want the distance from the column to the rail to be as large as possible to provide a long lever as well. If the distance from the column to the rail is short, it will be more likely that the rail will flex. The rail will always have a certain amount of flex, the larger the distance of the rail to the column, the lesser the head will rotate due to this flex. J
Hey Joe when you went to a single belt setup what did you do for your pulley adjustment? I noticed after changing mine that there isn't a very good way to adjust the belt with the factory geometry.
On my mill, the motor moves on a pivot. I just picked the right belt size so it would tighten up when I moved the motor back. There is a thumbscrew on the right side of the head near the back that acts like a grub screw to lock a spring plunger.
If you want further rigidity fill the column and base with epoxy granite.
Stock weight for the Enco RF-30 is 300 KG, times 2.2 is 660 pounds. Table/stand weighs 200 to 300 pounds, usually. that vise weighs an extra 100 pounds... My RF-30 has the Z Axis power feed, which is another 10 KG. (22 pounds) which makes it an RF-31... All the clones are similar in weight. If you go and verify it, you will find the exact same typo errors, and Engrish descriptions, with the words SOLT for SLOT for an example, in the manuals, that have the exact same date stamp of 1996 on the covers, for the JET and Central Machinery Mills... HFT number is #33686 for the 12 speed unit that is identical copy of the Enco RF-30.
You have added some serious value to that round column mill!!!!
Your linear bearing add-on looks like the best mod to get accuracy when raising or lowering the head...... how accurate is it?
+lornie212 It is very accurate as long as you don't push on it. That 1" rail is very rigid but if you loosen the head and push pretty hard, it moves about .001" just raising and lowering though, the movement is negligible.
@@ReignOterror Did you purchase it or make it? I'm looking for something for my mill
Whatever your display is showing, it is not the frequency! 'Slip' in an induction motor would never reach over 50% without load. Slip at maximum load is normally around 4%. Much more than that and torque would drop and the motor freeze. I have four VFD systems, and they all give frequencies that match the RPM. It may be giving you the servo loop value- hard to say without more information.
I think 2800 rpm is a good speed. Any higher might overheat the spindle bearings. But you could upgrade those.
I really wanted to watch this video but had to stop a few minutes in before I got motion sickness...camera is all over the place
@cuppa joe please tell me what vice that is! I know this is an older video but I have the same vice and can’t tell the brand
Some great mods here. What size did you tap the spindle for your drawbar?
If memory serves me, it was either 1/2-13 or 7/16-20, the hole in mine was close to the tap size for one of these so I just ran a tap in then make the collar to match.
+Cuppa Joe Thanks for the reply. I have measured mine at 12.7mm (1/2"). Im a metric man so will prob tap M14 x 1.25
+Cuppa Joe Thanks for the reply. I have measured mine at 12.7mm (1/2"). Im a metric man so will prob tap M14 x 1.25
Oh, OK, I did not know you were talking metric. I tapped mine imperial. But whatever works I guess. If you have a lathe, make a tapping fixture. One ID fits over the splines on the quill and another ID to keep the tap in line. That way you can do it on the machine without removing the spindle.
+Cuppa Joe I basically just wondered if you had to drill the spindle out at all for a tap. M14 x 1.25 is pretty much spot on for the existing hole and its a pretty common tap as its spark plug size. Good advice about the tap guide, I will do that, thanks again
I don't get what you were saying about the vfd, when you added the load and you said the vfd compensates to keep the motor at 21 rpm, the spindle speed jumped way up...so it's not really keeping a steady rpm...
It is trying but the only feedback the vfd has is from the back emf of the motor. Not true closed loop performance like if you had an encoder or a tachometer on the motor. There is an inherant the delay in this type of system an thus the motor temporarily speeds up before stabilizing.
Joe, instead of the rod to eliminate the rotation of the head when it's raised and lowered, wouldn't it be easier to mount an indicator to the cast lower column and angle the arm of the holder axis to be non parallel to the column which would hold an indicator set to measure the rotation of the head during the raising and lowering of the head? I know that's a long sentence. Hope you can understand what I mean. If you knew the deflection, wouldn't it be fairly easy to tap the head back to a zero reading?
Hi Bill, There are many methods that could be used to indicate the head but with the rod, you don't have to, it just stays in line all the time.
Hello again Joe, would fixing the jack (my best guess on the name based on parts diagram) to the post reduce the rotation of the head? Any problems that you can see? I can't see a need for head rotation anyway. I hope the move is going better. What a nightmare.
Not really Bill, there is too much slop in the jacking mechanism. I tried fixing my elevation rack to the column a while ago and the head still moved way too much.
Thanks, that figures.
I'm 90% complete your draw bar mod for a grizzly knee mill but am having trouble identifying the torrington bearing you used....your assistance would be appreciated.
Victor Wheeler Victor, the cage assy. is a NTA-613 and the washers are TRB-613 but you can use anything that will fit your specific application, it's not critical.
Thanks for pointing me in the right direction! I'll have to go with the 815.
I finished it, works great! Thanks for the video and your help.
For your Drawbar mod, did you have to take out the spindle to tap the threads?
Billy T no, just run the tap in.
Cuppa Joe what size tap did you use for the draw bar?
Why not ditch the bearings for the X and Y which are terrible and put on better ones. The chinese ball screw bearing fit mine just fine. The modify the original acme I just threaded it 17 mm, bought a couple of nuts and was good to go. Lost a whole lot of slop. The reinforcing plates on the back of the column are a great idea. Currently am replacing the spindle drive bearing and the quill bearing using 2RS bearing to get rid of the need to grease. A problem with these machines is the quill holder rocks in the column. One thread got rid of that rocking by usings a car air spring, I am using a air cylinder as there is enough room in the front if one removes the rod which gives the depth when you put the electronic readout on the outside of the cover. If you have the spindle bearing out you can easily remove the entire sheet metal pan and the cylinder would fit to the back in the holes behind the quill holder. One reason to use the front is if something fails, it is much easier to remove and replace as you do not need to take the sheet metal safety pan off.
You should lower the limit on the VFD to something lower like 2400 or 2500, you are to close to the limit. My 2 cents
Thanks for the videos, Joe! I've watched each a couple times (going through them again now that I have my inherited RF-30 type round column mill). Here's what baffles me about the round column mills: why do they exist? My assumption is that the ground round column is significantly cheaper to manufacture than a dovetail column or knee. But is there also some other function to having it? I guess by rotating the head a bit you could theoretically mill a bit further down the table, then rotate the other way, re-align, and do it again on the other side to get a little bit larger work envelope in the one direction (at the expense of the other), but that is quite impractical. Obviously it wouldn't be any more work to move and re-indicate the workpiece. So is there some obscure function to the round column and rotating head that I don't see? Something you happily sacrificed by doing the linear rail mod?
Hi Jon, I think it is combination of cost and a perceived notion of increased functionality in that you can drill off table. Back when I got mine, they didn't have square column mills, my philosophy is if you dont like something, modify it!
That was fast! Glad to know I'm not just "not getting it". I spent six weeks building a new workbench (as I had time) to hold my lathe, this mill, and a surface grinder. Finished it two weeks ago, and got the mill moved here last weekend. Today I finally get to fire it up after wanting one for years and knowing it was coming for months. Eventually, after I finish making the drawers for the bench and getting things organized, I will have to do some of these mods. Thanks again!
One place where the round column is helpful is that you can let work hang off the back side of the table and you can swing the head around to get to it. A job where you might use this is repairing an axle that has a damaged hole for a wheel stud. You would swing the head around on a Bridgeport knee mill to do this job as well.
Gettin seasick here, Joe... Buy a tri-pod! Sorry, I can't watch anymore...
I've got the Grizzly version of the same machine. There is " slop " between the spline of the spindle and the spline-broached alum step pulley which drives the spindle. This means if you hold the spindle, you can very slightly rotate the pulley. This " slop " causes a problem with surface finish. I smeared heavy greaser on the spline which helped somewhat but didn't eliminate the problem. Any ideas ?
Mine is like that too but doesn't cause me problems with surface finish, it just makes a lot of noise.
Noise is an indication that something is wearing, and that noise is going to get louder as the mating parts increasingly wear.
Surface finish will be improved if this problem is corrected. One solution would be to put a "drag" on the alum spindle-drive pulley. Another would be several set-screws thru the drive pulley jamming a piece of teflon or other suitable polymer directly onto the spindle-spline. The polymer, especially teflon would deform under the pressure of the set-screw and fill the "slop" between the splines, while still allowing the spindle to move vertically.
Your thoughts....
I am happy with mine the way it is. It has made noise since day 1 and the surface finish is fine. Mine only makes noise when it is unloaded.
Play at 1.5x speed.
Hey Joe - I've completed my WrongFu inspired mods, and couldn't be happier the way they turned out:
www.hobby-machinist.com/threads/tips-for-owners-of-rong-fu-rf-20-rf-25-rf-30-rf-31-mill-drills.38796/#post-375850
Thanks again for sharing.
+Jason Cundall Wow Jason, That is awesome! Thanks for the link to the forum. I will be lurking there. I had no idea there were people talking about those mods, I am shocked. Your machine turned out great. I like the way you designed your brackets to hold the rail.
+Cuppa Joe thanks Joe! :)
The best thing about the arms is because they're quite thick, they almost self align. I haven't really knocked it about yet to try and get it dead true, but it's clocking at under a thou (0.02mm - I'm a metric man) over the length of the quill. I'm sure if I took an hour our so of loosening various brackets and methodically going through the them all as there's hardly any flex. It sure does help with stiffening up the column as well. :)