Thanks. It's been working well for quite a while now. The only issue I've had is that the cheap socket I used is getting chewed up on the end and sometimes doesn't want to engage the drawbar. I think a better quality (read harder) socket would work better.
Thanks Steve. The power drawbar was sort of a proof of concept to see if the impact wrench had enough power to do the job. I'll probably redesign it to make it more compact and functional. When that happens, I'll definitely add it to the project tutorials. Tom
+Emery Board Ingersol Rand makes good quality air tools as does Chicago Pneumatic. Not all made in the US any more, but it's much better than the Chinese junk that HF sells. Tom
Keith, The brass bushings have a shoulder on them and are pressed into the upper and lower plates. The bores are a slip fit on the top and a press fit on the bottom to strengthen the rod.attachment to the plate.The collets drop out on their own when the drawbar is unscrewed. You may want to invest in a better impact wrench.The Harbor Freight one that I used isn't worth the $10 I paid for it. Tom
I wondered what that noise was when you were loading and unloading. Damn, you're brilliant! A few drops of oil in the air inlet will keep the Chinese knockoff running a little longer. I got a lot of that stuff laying around, it makes a mess when the air flows, tho. They sure are handy, beats a ratchet.
Why would it cross thread? Both the collets and the drawbar are hardened and well aligned. I've been using it regularly for more than a year now with no problem. Similar setups are also available commercially (Kurt) for instance) and I've never heard of any problems with them either. Tom
If you grind a bevel on the end of the hex on your drawbar, perhaps a 30 degree angle that gives you a 1/4 inch bevel, it will make it easier for a socket to slip on the hex and self align. I'd go with a 6 point impact socket. With the bevel it will slide on the hex quite easily.
+drufzr600 It's a useful one. I just replaced the cheap ass impact wrench on it and it works great again. If you build one, don't use a Harbor Fright impact wrench. Tom
I have found that if you use the "Professional" grade pneumatic tools they hold up very well. The cheaper stuff is truly junk. This is an awesome and very useful project for those of us that spend time in front of a milling machine. Thank you for sharing this great idea.
Tom, great idea! How did you over come the friction that holds the r8 collet after the drawbar is loosened? I usually back the drawbar off a few turns and pop it loose with a brass hammer I attached to the other end of my drawbar wrench.
Yeah, it was a mistake using the Chi-junk impact wrench. It does the job, but the valve body leaks like a sieve. I have to turn the air off when I'm not using it. That's what you get for $19. Tom
Tom I assume that the brass guides are just to keep the top plate parallel when it moves but did you connect them to the top and bottom or are they free floating. Also does the collet drop out due to you holding down on the handle thus using the drawbar to push it out when reversing? Simple and very functional I'm starting down the journey to make one based on yours! Keith
The only issue I've noticed is that sometimes the socket doesn't want to engage with the hex on the drawbar and needs to be turned a bit to align. A dog clutch or something similar might work better. Tom
Toms Techniques Sometimes you can just press it against the nut and tap the butterfly ratchet switch and it will engage, but I guess over time it will round off the nut a bit but nuts can be replaced when needed. I am not sure it would be bad to just leave the wrench engaged with the nut without the spring suspension system as the air wrench will just free wheel without air pressure in it. But that might wear the cheap wrench out prematurely. But since they are so cheap who would care as it would be less frustrating using it being engaged with the nut continually. What are your thoughts on this? thanx.
I don't think leaving it engaged would work very well. Even if the bearing could take it, the air motor would act like a pump working against a closed valve. I wonder what commercial units use for a coupling, such as the one made by Kurt? Tom
Toms Techniques The harbor Freight unit is a copy of an American made tool I have and bought years ago used knowing it needed to be rebuilt. So i took it to an air tool repair facility to buy the parts and as it turned out the cost of just letting them do it was just a little more than the cost of the parts. So I let them do it and to my surprise they did it while I waited about ten minutes, and they did it right in front of me on the counter. These butterfly air tools have a small turbine that looks like a six tooth gear with deep cuts between each tooth. the tip of each tooth has a slit to hold a strip of phenolic material that is spring loaded somehow to push the material up against the cylinder wall, sort of like a wankle engine design. Air is introduced from both sides depending on if its to push it forward or reverse. So if this turbine was spun without air under pressure it to me from my observation would logically just rotate what air was there without building up any pressure. But now you have me thinking so will have to do an experiment and drive mine with another tool to see if it does build any pressure, but my suspicion at this point is that it won't., but i have been known to be wrong assuming stuff in the past, so we shall find out. If it turns out it does not build pressure then that would make this upgrade much simpler for folks to do, less parts.
That butterfly impact is now on clearance for 12.99$ if you can find it I'm making one but opting for linear ball bearings and a 3rd rail to help ensure smooth operation Thanks for the idea
Great tool Tom, especially for a short guy like me. I need a small step stool to get at the drawbar on my Sharps mill. I have all the components ready to build on except the long brass bushings. May I ask where you got them?
I made them from some brass rod I had on hand. The upper ones could be steel because their only purpose is to stiffen the rods. The lower ones could be steel as well if you bush the ends so they slide easily. Oilite or plastic bushings would work fine. McMaster Carr carries a good selection. Tom
This whole exercise was too see if an impact wrench like this could generate enough torque to reliably hold an end mill. After a bunch of trial runs, I've found that it only takes a few seconds to generate adequate torque. It's really no different than figuring out how tight to make the drawbar with a wrench.
I can shoot a close-up of the power drawbar to show how I did it, but you'll need to work out the details yourself since there are so many variations of mills and impact wrenches. Maybe I can throw something together this weekend. Tom
Been using it daily for more than six months and it works great. The drawbar and collets are hardened so it should be fine.
The impulses from the impact wrench knocks it loose. I've never had to use a hammer on the drawbar.
Tom
more brilliance Tom, thanks so much for sharing your skills/experience/talents...BRAVO!!!
Thanks. It's been working well for quite a while now. The only issue I've had is that the cheap socket I used is getting chewed up on the end and sometimes doesn't want to engage the drawbar. I think a better quality (read harder) socket would work better.
That's brilliant, Tom. When watching/hearing you change tools in your other videos, I just assumed that you had a factory power draw bar.
Thanks.
Right now it's just a prototype. Eventually I'd like to redesign it to be more compact.
Tom
The air compressor is one of the most used tools in my shop. Ya gotta have compressed air!
Tom, great job on the power drawbar. I hope the drawbar makes it on your site as an intermediate or advanced project.
Thanks Steve.
The power drawbar was sort of a proof of concept to see if the impact wrench had enough power to do the job. I'll probably redesign it to make it more compact and functional. When that happens, I'll definitely add it to the project tutorials.
Tom
Tom, Thank you for linking me to this project it is one of my next projects.
buchanan1a
NP,
Just don't make the same mistake I did and use a Harbor Fright impact wrench. Spend a few bucks more and get one of better quality.
Tom
+Toms Techniques which brand do you recommend for longevity? The last harbor freight air tool I got lasted a few days!
+Emery Board
Ingersol Rand makes good quality air tools as does Chicago Pneumatic. Not all made in the US any more, but it's much better than the Chinese junk that HF sells.
Tom
Nice job, I like the handle!
Keith,
The brass bushings have a shoulder on them and are pressed into the upper and lower plates. The bores are a slip fit on the top and a press fit on the bottom to strengthen the rod.attachment to the plate.The collets drop out on their own when the drawbar is unscrewed.
You may want to invest in a better impact wrench.The Harbor Freight one that I used isn't worth the $10 I paid for it.
Tom
I wondered what that noise was when you were loading and unloading. Damn, you're brilliant! A few drops of oil in the air inlet will keep the Chinese knockoff running a little longer. I got a lot of that stuff laying around, it makes a mess when the air flows, tho. They sure are handy, beats a ratchet.
Tom,
Very cool. I am going to copy with pride! Chuck
Excellent. Just do yourself a favor and spring for a better quality impact wrench. The Harbor Fright one has been nothing but trouble.
Tom
Why would it cross thread? Both the collets and the drawbar are hardened and well aligned. I've been using it regularly for more than a year now with no problem. Similar setups are also available commercially (Kurt) for instance) and I've never heard of any problems with them either.
Tom
Sorry, no sketches. I just kind of made it to suit the impact wrench.
Damm thats so damm simple ..well done
Thanks, it's a handy add on for your mill.
Tom
That's awesome! I'm going to try that one, thanks!
If you grind a bevel on the end of the hex on your drawbar, perhaps a 30 degree angle that gives you a 1/4 inch bevel, it will make it easier for a socket to slip on the hex and self align. I'd go with a 6 point impact socket. With the bevel it will slide on the hex quite easily.
Wouldn't a 12 point socket make it twice as likely to engage the hex?
Very nice, Thanks for sharing!
Very nice.👍
That is nifty, I like it.
+Pete Macrae
Thanks. It works well when the impact wrench behaves.
Another project to add to the list
+drufzr600
It's a useful one. I just replaced the cheap ass impact wrench on it and it works great again. If you build one, don't use a Harbor Fright impact wrench.
Tom
I have found that if you use the "Professional" grade pneumatic tools they hold up very well. The cheaper stuff is truly junk. This is an awesome and very useful project for those of us that spend time in front of a milling machine. Thank you for sharing this great idea.
Nice addition! Does the wrench have a torque cutout or are you just careful when tightening it in?
Excellent !
Outstanding
This small impact wrench generates about the same torque as a wrench. I've tried over doing it and it doesn't seem to matter.
Nice!!....sure beats my speed handle tha is on my channel...lol, got any rough sketches to share?
Tom, great idea! How did you over come the friction that holds the r8 collet after the drawbar is loosened? I usually back the drawbar off a few turns and pop it loose with a brass hammer I attached to the other end of my drawbar wrench.
I am also wondering how the collets are released. On the video it looks like the collet just fell out. It does not do that on my bridgeport. ??
Yeah, it was a mistake using the Chi-junk impact wrench. It does the job, but the valve body leaks like a sieve. I have to turn the air off when I'm not using it. That's what you get for $19.
Tom
Tom I assume that the brass guides are just to keep the top plate parallel when it moves but did you connect them to the top and bottom or are they free floating. Also does the collet drop out due to you holding down on the handle thus using the drawbar to push it out when reversing?
Simple and very functional I'm starting down the journey to make one based on yours!
Keith
I have similar setup on my mill, works great.
The only issue I've noticed is that sometimes the socket doesn't want to engage with the hex on the drawbar and needs to be turned a bit to align. A dog clutch or something similar might work better.
Tom
Toms Techniques
Sometimes you can just press it against the nut and tap the butterfly ratchet switch and it will engage, but I guess over time it will round off the nut a bit but nuts can be replaced when needed. I am not sure it would be bad to just leave the wrench engaged with the nut without the spring suspension system as the air wrench will just free wheel without air pressure in it. But that might wear the cheap wrench out prematurely. But since they are so cheap who would care as it would be less frustrating using it being engaged with the nut continually. What are your thoughts on this? thanx.
I don't think leaving it engaged would work very well. Even if the bearing could take it, the air motor would act like a pump working against a closed valve. I wonder what commercial units use for a coupling, such as the one made by Kurt?
Tom
Toms Techniques
The harbor Freight unit is a copy of an American made tool I have and bought years ago used knowing it needed to be rebuilt. So i took it to an air tool repair facility to buy the parts and as it turned out the cost of just letting them do it was just a little more than the cost of the parts. So I let them do it and to my surprise they did it while I waited about ten minutes, and they did it right in front of me on the counter. These butterfly air tools have a small turbine that looks like a six tooth gear with deep cuts between each tooth. the tip of each tooth has a slit to hold a strip of phenolic material that is spring loaded somehow to push the material up against the cylinder wall, sort of like a wankle engine design. Air is introduced from both sides depending on if its to push it forward or reverse. So if this turbine was spun without air under pressure it to me from my observation would logically just rotate what air was there without building up any pressure. But now you have me thinking so will have to do an experiment and drive mine with another tool to see if it does build any pressure, but my suspicion at this point is that it won't., but i have been known to be wrong assuming stuff in the past, so we shall find out. If it turns out it does not build pressure then that would make this upgrade much simpler for folks to do, less parts.
Toms Techniques
I am not familiar with the Kurts setup, is it air driven also?
That butterfly impact is now on clearance for 12.99$ if you can find it
I'm making one but opting for linear ball bearings and a 3rd rail to help ensure smooth operation
Thanks for the idea
There is a reason it's $12.99. I replaced the one I used early on with one of better qualty. Yes, it cost more, but it was money well spent.
Great tool Tom, especially for a short guy like me. I need a small step stool to get at the drawbar on my Sharps mill. I have all the components ready to build on except the long brass bushings. May I ask where you got them?
I made them from some brass rod I had on hand. The upper ones could be steel because their only purpose is to stiffen the rods. The lower ones could be steel as well if you bush the ends so they slide easily. Oilite or plastic bushings would work fine. McMaster Carr carries a good selection.
Tom
What stops the drawbar from cross threading? I would hate to strip the threads on one of my tool holders or collet. Take care, be safe!
Love the lever idea, but aren't you afraid of cross threading?
tom - really coool idea. :-)
Buddy you are too clever ... how do you sleep... I get it you don't lol Good job
Lol.
There is way too much to do, to waste time sleeping.
Hi! I'm pretty sure that it has been asked to you already.. but i couldn't find it --> what milling machine is it? Looks very good. Thank you!!
+Flavio Luis Gino Bertolini
It's a DoAll 200V knee mill. I bought it new in the mid 80's and it has served me very well.
Tom
+Toms Techniques I see. Thank you very much for your reply.. and thank you for sharing the videos too :)
Rather unique! Thanks....13
How do you know if the collet is tight enough? Had an endmill slip and ruined an expensive part. Have been using a torque wrench ever since.
This whole exercise was too see if an impact wrench like this could generate enough torque to reliably hold an end mill. After a bunch of trial runs, I've found that it only takes a few seconds to generate adequate torque. It's really no different than figuring out how tight to make the drawbar with a wrench.
My mill looks the same except for the variable speed! (Mine is belt driven and NT30 arboured). How did you attach your set up to the top of the mill?
I picked three existing screws with the baseplate of the drawbar. All Bridgeport clones should have them.
@@TomsTechniques Thanks Tom, I'll have another look at mine.
Does the hammer action break the collet free?
I have to whack the end of the draw bar to break the collets free.
Yes it does, every time.
Tom
do you have a drawing for the handle...im deff doing this upgrade
No. You'll just have to design it to suit the impact wrench you use.
@@TomsTechniques im going to use the butterfly...neiko...ill figger it out....thank you for doing the video :)
awesome
Tom: I copied your idea. It works great. However, I have now lost the exercise that I used to enjoy? turning the draw bar with a wrench.
Have you had any problems cross threading the quill?
None at all. I've been using it regularly for over a year.
Tom
Make a video and show us how its done thank you for the video
I can shoot a close-up of the power drawbar to show how I did it, but you'll need to work out the details yourself since there are so many variations of mills and impact wrenches. Maybe I can throw something together this weekend.
Tom
nice thanks for the idea, ill be pinching it :-)
What psi is it set to?
It's unregulated, so anywhere from 80-110 psi.
GOT ANY FOR SALE.
Nope. Gotta design them for you mill and impact wrench. The principle is the same.