It turned out nice! .0005" over 24" is pretty good especially for a quick grind! I bet most of that is from not running flood coolant so you had more heat in the middle of the part than the ends and when it cooled you got the bow. It takes only about 15deg of heat differential for that much error.
Nice job Keith, Brian Block was correct on the heat build up causing the bow in the center. One way you can reduce that is to place the straight edge at angle on your magnet. It reduces the contact of the cut on the part and helps a lot to reduce heat. The draw back is that it takes longer to traverse across the part but this also allows your mister more time for cooling. .0005" over 24" on a machine that old without flood coolant is amazing. Steve
Pretty good chance the slight bow was present off the mill, and the mag chuck pulled it down, distorting the part. The grinder probably got it flat, and then some bow returned when the mag chuck released.
Ya. we would generally shim the bottom on the first grind so the magnet wouldn't pull it down. Equalize the warp in this case with a half thousand on the 2 edges or something like that.
.0005 is nothing but I know it bothers you as it would me:-) . My grinder is worn also. But its 100 times better than no grinder. I love your old grinder Keith, its a perfect one to rebuild. Love the videos and appreciate the hard work you put into them.
Watched both yours and Abom's. Different approaches to the same job, always interesting to see. Oftentimes there doesn't seem to be one "right" way to do things.
Adam loves his shaper and wants to use it for every job that is possible. I can't remember if we saw him inspect it after the shaper, and how much scraping he needs to do? That's assuming that he will be scraping it.
Could you put a test indicator on the finished ground part still on the grinder with the mag chuck energized and again with the mag chuck deenergized to what affect the magnetism has on the shape of the part while being held in place, maybe the placement of the support blocks is bowing the part when grinding
We C-clamp the piece onto a 90 degree angle plate for the first cut, then mag down the plate. After one edge is straight, you can mag it down directly, grind the other edge, then flip it over and re-grind the first edge. One of the "interesting" things about hardened steel is that internal stresses will cause the piece to warp as you remove the outer (hardest) material, similar to wood. Not much, but enough to make a measurable difference. Measurable by some of our customers, anyway. We work in tenths, they measure in millionths. Also, every surface grinder gives a better finish and more accurate cut going in one direction (in and out) than the other. That's a function of wear on the ways, not the nature of the machine itself. I'm a jig grinder by trade - we're the nerds of the machining industry.
Maybe setting the camera above you looking down at the mag chuck would make it easier to see the grinding? I know I would enjoy seeing better! Just a thought. Love your content Keith keep it up! Happy Holidays !!!!!
What is the Norton stone? General suggestion for all of your videos. It would be helpful if a list of special tools and products were provided in your description.
That'll just have more people whining, "well, as a [crotch] grinder of 45 years, you know that stone is good for cast iron that is over 17.5 months old, your CI isn't seasoned that long, so you should be using xx wheel."
Keith, you said you were using a special Norton wheel made for grinding cast iron. What is its specifications? I.e., abrasive, grit size(s), grade, structure, & bond? I used to spend a lot of time in our Grinding Shop at work and never saw wheels being dressed like you did, but we never ground cast iron either. Is that dressing technique what Norton recommends for that wheel? I'm curious because I hope to find an "available" surface grinder down here in central Florida one of these days and have a lot to re-learn about grinding.
Don’t know if you have ever tried it but many years ago we used to “load” the cutting face of our grinding wheel by pressing it with a hard wood board such as oak during final rub out stages. Seemed to improve the final finish and even out the surface..
Sharklops Yes I believe that is an accurate description. We used the same technique on large wheels on the cylindrical grinder on hardened steel, hard Crome and spray metal coatings
My guess is that when you start scraping you will find the part low in center and high on the ends. When your grinder table reverses direction the ends are plunging down and grinding less away than in the center. On your 45 degree surface, the parallelism of that angle to the base is only going to be as good as the precision of those magnetic blocks
Sir, first of all. Thank you for the great content you put out. I enjoy watching all your videos. I'm a total idiot having used a surface grinder only once when I was 15, with all but satisfactory results. I do have a couple of questions though. 1. How big of an effect does heat have while grinding? If you are measuring to the degree shown in some of Tom Lipton's and the like's videos? Do you let the part cool down between passes? 2. Could the taper on the dovetail side not have been due to not having the perpendicular "back face" ground in before swapping over to the front? (All being equal and the mag transfer blocks being true) Maybe I'm totally missing the surface here. Thank you again for the way you transferring your knowledge through your videos.
What type, grade and grit (my guess on the grit is 32) is the wheel? I have a Republic SG, but haven't tried grinding CI yet, and have tons of new and used wheels, mostly unlabeled.
Hey I recognize those V blocks! Also- I'm the only guy in the world that already has a Rucker scraped straight edge thanks to my luck at the Bash. The big one is looking good, Keith! ----Aaron
I want to scrape in a lathe but my surface grinder only has 630mm of travel. I need a 1200mm straight edge. Is there a way for me to grind one on the surface grinder? I don't have a big surface plate either.
Keith, the sparking on the left side when the wheel is moving right to left is less than when it starts on the piece from left to right. Could that be from the wheel picking up some of the scarf that is on the end of the left end of the piece?
The taper on the 45 degree angle would make me suspect the v-blocks the straight-edge is sitting on - it is not sitting directly on the magnetic chuck after all. Also if I watch the grinder, it seems to always grind a little heavy starting on a stroke but never ending, both ways. Seems to me the table is rocking a little. This would explain the "hinge" on the surface plate. Still, plenty accurate enough to prepare for a scraping class :)
Did you mag the piece down when you did the initial grind on the upper surface? The bottom wasn't ground flat at that stage, so I think (but I['m not sure) that it SHOULDN'T be magged down.
Perfectly thought through and described. It takes a special sort of mind to show us how the base is 4thou hollow and then mag it down to machine an opposing surface. I was trying not to get upset by this and I ended up accepting that Keith is not as good at this as he would like us all to think.
@@jonka1 Given that Keith has already showed and explained this effect when tuning the surface grinder and mag-chuck in a recent video, I suspect the detail I'm asking about was merely "off camera", hence my question
Sparking out means to continue passes at that depth of cut until you longer see material being ground off. The magnetic chuck definitely flexes the part.
Keith, I'd think the .004 you started with before grinding combined with the magnetic chuck is why you ended up with .0005 variance. Keep up the effort, you do very good job producing these videos.
Probably will have a thou to scrape in the end since you aren’t using flood coolant. Mist is okay but can’t beat flood coolant if you want to get down into the millionths.
Yes, it does. But the leading side of the wheel wears, while the trailing edge remains almost full diameter. So as it steps across the part, the leading edge removes the bulk of the material and the trailing edge cleans it up. You'll sometimes see them grind it with a "full (wheel) width step over" so the wheel doesn't get that angle induced into it.
That's ok. Just pattern one up, send it to a foundry, have them make a few prototypes, and then sell them to your vast machinist network. Or buy a rough cast straight edge from someone else, so you can have a project scraping it in. Or better yet, buy a finished straight edge. (Psssst, they're all more expensive.)
I wish people would instead say they used 'inexpensive' tools instead of presuming 'Chinese' or 'import' always means lower quality. They are entirely capable of making high quality parts if you're willing to pay for them, and other countries like US/Germany/Swiss etc product will likely have the same issues at the same lower price points, and probably even worse.
@@scottr939 Agreed. It's the sign of our times. Having just watched Stefan G bring a Chinese six jaw vice up to his spec his initial thoughts were it had good tolerances.
It turned out nice! .0005" over 24" is pretty good especially for a quick grind! I bet most of that is from not running flood coolant so you had more heat in the middle of the part than the ends and when it cooled you got the bow. It takes only about 15deg of heat differential for that much error.
That little Rucker edition is great
Nice job Keith,
Brian Block was correct on the heat build up causing the bow in the center. One way you can reduce that is to place the straight edge at angle on your magnet. It reduces the contact of the cut on the part and helps a lot to reduce heat. The draw back is that it takes longer to traverse across the part but this also allows your mister more time for cooling. .0005" over 24" on a machine that old without flood coolant is amazing.
Steve
Thanks Keith
Pretty good chance the slight bow was present off the mill, and the mag chuck pulled it down, distorting the part. The grinder probably got it flat, and then some bow returned when the mag chuck released.
Ya. we would generally shim the bottom on the first grind so the magnet wouldn't pull it down. Equalize the warp in this case with a half thousand on the 2 edges or something like that.
A bit of the good old electro-flaking scraping action will fix that.
We could all see it coming.
The casting on your own straight-edges are beautiful!
You know... That is casting of liquid metal, not casting of a role in a play or film...
I don't know--bots these days!!!
Thankf for all the great videos!
thanks for all the effort and energy..
Thanks. I just build a base for my Prazi mill and am now tramming it in. Thanks for showing me what precision to expect.
I am glad you take the time to video your work such as grinding the strait edge. I'll keep watching for what's next.
Great work Keith. Grinder work great. Thank you for sharing
Nice work and thank you for sharing.
.0005 is nothing but I know it bothers you as it would me:-) . My grinder is worn also. But its 100 times better than no grinder. I love your old grinder Keith, its a perfect one to rebuild.
Love the videos and appreciate the hard work you put into them.
Really love your channel.... Brings back so many memories of trade school and in the field....
Keith, Nice job on the grinding of your straight edge thanks for sharing.!.!.!.
"Getting down to the short rows" I haven't heard that one in a long long time Keith. I love your channel. Thanks for sharing.
I haven't heard that saying since I stopped working as a tobacco field hand in 1986
@@feeseize9569 it must of been 72 for me Fee. Great to hear it again!
Watched both yours and Abom's. Different approaches to the same job, always interesting to see. Oftentimes there doesn't seem to be one "right" way to do things.
Adam loves his shaper and wants to use it for every job that is possible. I can't remember if we saw him inspect it after the shaper, and how much scraping he needs to do? That's assuming that he will be scraping it.
Found myself hypnotized after a few moments of watching that table reciprocate like that.
It's a little less interesting after a few hours, and even less so after a few decades. Beats cranking handles, though.
Could you put a test indicator on the finished ground part still on the grinder with the mag chuck energized and again with the mag chuck deenergized to what affect the magnetism has on the shape of the part while being held in place, maybe the placement of the support blocks is bowing the part when grinding
We C-clamp the piece onto a 90 degree angle plate for the first cut, then mag down the plate. After one edge is straight, you can mag it down directly, grind the other edge, then flip it over and re-grind the first edge. One of the "interesting" things about hardened steel is that internal stresses will cause the piece to warp as you remove the outer (hardest) material, similar to wood. Not much, but enough to make a measurable difference. Measurable by some of our customers, anyway. We work in tenths, they measure in millionths. Also, every surface grinder gives a better finish and more accurate cut going in one direction (in and out) than the other. That's a function of wear on the ways, not the nature of the machine itself.
I'm a jig grinder by trade - we're the nerds of the machining industry.
Maybe setting the camera above you looking down at the mag chuck would make it easier to see the grinding? I know I would enjoy seeing better! Just a thought. Love your content Keith keep it up! Happy Holidays !!!!!
Plese do tell more about what norton stone u are using for the cast iron . Love your videos and appreciate all the knowledge u share with us
Keith doing the grind LOL Good Job
Nice!! Perfect job for "flat rate" pricing... :-)
Thank you Keith! Can you tell us more about the wheel you are using?
What is the Norton stone?
General suggestion for all of your videos. It would be helpful if a list of special tools and products were provided in your description.
Put "Norton Stone" into google and you will find your answer :)
That'll just have more people whining, "well, as a [crotch] grinder of 45 years, you know that stone is good for cast iron that is over 17.5 months old, your CI isn't seasoned that long, so you should be using xx wheel."
Keith, you said you were using a special Norton wheel made for grinding cast iron. What is its specifications? I.e., abrasive, grit size(s), grade, structure, & bond? I used to spend a lot of time in our Grinding Shop at work and never saw wheels being dressed like you did, but we never ground cast iron either. Is that dressing technique what Norton recommends for that wheel? I'm curious because I hope to find an "available" surface grinder down here in central Florida one of these days and have a lot to re-learn about grinding.
Don’t know if you have ever tried it but many years ago we used to “load” the cutting face of our grinding wheel by pressing it with a hard wood board such as oak during final rub out stages. Seemed to improve the final finish and even out the surface..
interesting. does that basically burnish the surface?
Sharklops
Yes I believe that is an accurate description. We used the same technique on large wheels on the cylindrical grinder on hardened steel, hard Crome and spray metal coatings
Will the wood not clog up the stone for the next grind? (Sorry I'm the shop idiot here)
Jaco Badenhorst
You would normally redress the wheel for the next work piece. Plus the wheel is braking down during the rough grinding process
My guess is that when you start scraping you will find the part low in center and high on the ends. When your grinder table reverses direction the ends are plunging down and grinding less away than in the center. On your 45 degree surface, the parallelism of that angle to the base is only going to be as good as the precision of those magnetic blocks
In case anyone is interested, a half thou in 24" is an angle of ONLY 0.00119º.
4.32 seconds.
Whats intresting is a stright edge is 0 degrees.
@@davidl.579most Starrett straight edges are +-.0002" per foot.
Sir, first of all. Thank you for the great content you put out. I enjoy watching all your videos. I'm a total idiot having used a surface grinder only once when I was 15, with all but satisfactory results. I do have a couple of questions though.
1. How big of an effect does heat have while grinding? If you are measuring to the degree shown in some of Tom Lipton's and the like's videos? Do you let the part cool down between passes?
2. Could the taper on the dovetail side not have been due to not having the perpendicular "back face" ground in before swapping over to the front? (All being equal and the mag transfer blocks being true)
Maybe I'm totally missing the surface here.
Thank you again for the way you transferring your knowledge through your videos.
What type, grade and grit (my guess on the grit is 32) is the wheel? I have a Republic SG, but haven't tried grinding CI yet, and have tons of new and used wheels, mostly unlabeled.
I’ve watched this video several times and still find it engrossing.
I assume the 9" Rucker straightedge you're selling is rough cast. Will you be selling any that are milled, ground and scraped?
What Norton stone were you using for this cast iron job?
Hey I recognize those V blocks! Also- I'm the only guy in the world that already has a Rucker scraped straight edge thanks to my luck at the Bash. The big one is looking good, Keith! ----Aaron
Keith could you then use a lapping machine to get a flatter surface?
Hey Keith. On the straight edge that you are selling, Would that be for an un ground straight edge? Thanks, Eric
I want to scrape in a lathe but my surface grinder only has 630mm of travel. I need a 1200mm straight edge. Is there a way for me to grind one on the surface grinder? I don't have a big surface plate either.
Lol subtitles” we’re taking about a half a cow on the death “
Sort of O/T, however what sort of protectant to you use after grind/shaping to keep rust off?
Keith, the sparking on the left side when the wheel is moving right to left is less than when it starts on the piece from left to right. Could that be from the wheel picking up some of the scarf that is on the end of the left end of the piece?
Yes I noticed that too. Maybe wear in the table slides, or an artifact of the drive mechanism.
Hiya Keith
The taper on the 45 degree angle would make me suspect the v-blocks the straight-edge is sitting on - it is not sitting directly on the magnetic chuck after all.
Also if I watch the grinder, it seems to always grind a little heavy starting on a stroke but never ending, both ways. Seems to me the table is rocking a little. This would explain the "hinge" on the surface plate.
Still, plenty accurate enough to prepare for a scraping class :)
What is the make and model of the indicator stand your using? It's beautiful!
It was seen in the visit from the grinder guys. (name escapes me). It wasn't cheap.
This video;
ruclips.net/video/PRKOiiXzGAM/видео.html
Solid Rock Machine Co. $850.00
Just a quick Q... did you indicate the part when you milled the 45* angle in the last video?
@23:16 I see you Keith.
When you scrap your planner is it only for oil retention and reduced friction? Is the grinding going to need truing?
The grinding will need tuning but the other things you mentioned are a big reason to do it aswell
Did you mag the piece down when you did the initial grind on the upper surface? The bottom wasn't ground flat at that stage, so I think (but I['m not sure) that it SHOULDN'T be magged down.
Perfectly thought through and described. It takes a special sort of mind to show us how the base is 4thou hollow and then mag it down to machine an opposing surface. I was trying not to get upset by this and I ended up accepting that Keith is not as good at this as he would like us all to think.
@@jonka1 Given that Keith has already showed and explained this effect when tuning the surface grinder and mag-chuck in a recent video, I suspect the detail I'm asking about was merely "off camera", hence my question
When you spark out, is that do to the metal flexing to give a high point ?
Sorry never saw this done. Thanks.
Sparking out means to continue passes at that depth of cut until you longer see material being ground off. The magnetic chuck definitely flexes the part.
Keith, I'd think the .004 you started with before grinding combined with the magnetic chuck is why you ended up with .0005 variance. Keep up the effort, you do very good job producing these videos.
@@nelsonashbrook765 Thanks for your reply
I wonder if the grinding wheel is picking up the filings at the end of the piece and causing sparks and finish problems on the ends.
Was wondering the same thing.
Why not use flood colant?
Probably will have a thou to scrape in the end since you aren’t using flood coolant. Mist is okay but can’t beat flood coolant if you want to get down into the millionths.
Keith, I need the link to purchase the straight edge.
How much cross feed per table pass do you normally use when running in automatic?
9” 👍🏻👍🏻
doesn't the wheel diameter shrink or wear away as your grinding?
Yes, it does. But the leading side of the wheel wears, while the trailing edge remains almost full diameter. So as it steps across the part, the leading edge removes the bulk of the material and the trailing edge cleans it up. You'll sometimes see them grind it with a "full (wheel) width step over" so the wheel doesn't get that angle induced into it.
What speed you running the stone?
And what grit
Can anyone tell me what the material is of the device used to true-up the grinding wheel? Or what that device is called?
I believe it’s called a dressing stone and it’s normally made of diamond.
Tim Finch thank you!
@@Hoaxer51 Tim think it may be a single point diamond.
Nice Job, but could you pls. clean up your Surface Grinder a little bit?
You should really be using flood coolant when surface grinding.
150 for a rough camel back seem very expensive for me
That's ok. Just pattern one up, send it to a foundry, have them make a few prototypes, and then sell them to your vast machinist network. Or buy a rough cast straight edge from someone else, so you can have a project scraping it in. Or better yet, buy a finished straight edge. (Psssst, they're all more expensive.)
If it's wrong blame the Chinese.
I wish people would instead say they used 'inexpensive' tools instead of presuming 'Chinese' or 'import' always means lower quality. They are entirely capable of making high quality parts if you're willing to pay for them, and other countries like US/Germany/Swiss etc product will likely have the same issues at the same lower price points, and probably even worse.
@@scottr939 Agreed. It's the sign of our times. Having just watched Stefan G bring a Chinese six jaw vice up to his spec his initial thoughts were it had good tolerances.
Sounds like a grinding project on the v blocks .
Gotta blame somebody, might as well blame China 😊, years and years ago we blamed Japan. I agree, you usually get what you pay for.
Boring.
No, that would be the video of him enlarging an internal diameter on the lathe. There's a special tool for that.