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Tool and cutter grinder build
- Thread starter Mark_f
- Start date
Well, Today was a repair day. I noticed a problem with the micrometer adjustment on the front bar. this grinder is somewhat based on the Bonelle, but I used the micrometer design from the Quorn. The problem is when the front bar is rotated to tilt the work head into the wheel, it also tends to turn the micrometer , thus changing your setting. The Quorn didn't seem to have any way to prevent this. the Bonelle did but it only worked in one direction. The Bonelle lock mechanism, let the micrometer back off when tilting out but the lock stopped it at the setting when rocked back in. I did not like this, even though it would work ok. I want the lock to lock the micrometer setting and keep it there no matter what. This meant a revision and a new micrometer knob. I wanted to make a new knob anyway as I think the micrometer should be a class 3 fit at best. mine was made with a tap and die and was probably a sloppy class 1 fit. Since I made the internal threads with a tap, I would make a new knob assembly and single point the threads to a perfect fit.
This is the old micrometer screw.
This is the new one. single pointed threads to a perfect fit , in fact I left the threads just a teeny weensy bit tight so it takes a tiny bit of effort to turn. they are snug but very smooth. I couldn't ask for anything better. Now , the revision. There is a stub sticking out of the screw knob 1" in diameter and 3/8" long. I will borrow some of the idea from the Bonelle here. There will be a stud where the screw is to the left and an arm with a 1" bore and a pinch lock between the stud and the knob. when the micrometer is set, the pinch lock tightened , the micrometer cannot move at all until it is loosened. I also made the new nob 2" in diameter instead of 1 3/4". I will make the lock arm a little later when I have the rotary table set up on the mill.
This is the old micrometer screw. This is the new one. single pointed threads to a perfect fit , in fact I left the threads just a teeny weensy bit tight so it takes a tiny bit of effort to turn. they are snug but very smooth. I couldn't ask for anything better. Now , the revision. There is a stub sticking out of the screw knob 1" in diameter and 3/8" long. I will borrow some of the idea from the Bonelle here. There will be a stud where the screw is to the left and an arm with a 1" bore and a pinch lock between the stud and the knob. when the micrometer is set, the pinch lock tightened , the micrometer cannot move at all until it is loosened. I also made the new nob 2" in diameter instead of 1 3/4". I will make the lock arm a little later when I have the rotary table set up on the mill.
I decided to finish up the micrometer bar today. I learned something today also. I made the split cotter for the front bar clamp from steel. The bar is steel and the frame is steel. I found the cotter would not grip good enough, so I made another one from aluminum. The aluminum cotter grips much better. I only have one other steel cotter and it seems to be ok, but it is also twice as big. So it seems the cotters made from softer metal work better than a hard cotter.
I also noticed that since making the new micrometer screw with a better fit, the micrometer stays put when the bar is rotated. it seems the micrometer lock won't be needed, but I will make it later just in case. I center drilled the end of the front bar and used Lok-tite to secure a 3/8 steel ball bearing in the end of the bar. This is so the contact point between the bar and the micrometer screw is very small. This reduces friction to almost none , especially with a little dab of light grease on the end of the screw. this also is why the micrometer stays put when the bar is rotated.
These are the parts for the other end of the micrometer. Some springs, a thrust bearing and the end cap. I was experimenting with different springs as I did not know how heavy they need to be. The combination I have seems to be pretty good. The long spring goes in a hole drilled in the end of the front bar and presses against the rear end of the cap. There is a 5/16" steel ball bearing in the hole in the bar for the spring to seat against. this greatly reduces any friction for rotation of the bar. The second spring is a heavier spring and seats between the end of the bar and the thrust bearing in the end of the cap. This eliminates any friction here also. With this set up the micrometer works extremely smooth and effortlessly. I can over come the springs, but it takes both hands. There is a good bit of pressure to keep the tool against the grinding wheel. One advantage to this arrangement , is the tool travel towards the stone is a solid stop. Any give to over come the spring would move the tool AWAY from the grinding wheel, But that won't happen as the grinding force is light. This machine is not meant to do heavy grinding.
This is the end cap installed with the springs and bearings. I will make a print to match this setup. I started out building a Bonelle grinder with a few of the Quorn features, but a while back I abandoned that plan and have been building what I want as I go Because the Bonelle had some short comings and the Quorn had a lot of short comings. I guess this is why no two are ever alike.
I also engraved the 360 degree markings on the tool holder index wheel and stamped the numbers. the numbers are stamped 0 - 10 - 20 - 30 - 40- 40 - 30 - 20 - 10 - 0. This sequence is repeated in every 90 degree quadrant. In reading what I found on the Quorn and Bonelle, This has to something to do with indexing tools to sharpen. I personally was just going to number 0 - 360, but still can later if desired. ( I would just machine the numbers off and re stamp them).
When I mark the rotary base table, I will mark it every 5 degrees as it is only 3 inches in diameter. This one was 4 inches diameter and the lines are close. My eyes aren't that good.
I also noticed that since making the new micrometer screw with a better fit, the micrometer stays put when the bar is rotated. it seems the micrometer lock won't be needed, but I will make it later just in case. I center drilled the end of the front bar and used Lok-tite to secure a 3/8 steel ball bearing in the end of the bar. This is so the contact point between the bar and the micrometer screw is very small. This reduces friction to almost none , especially with a little dab of light grease on the end of the screw. this also is why the micrometer stays put when the bar is rotated.
These are the parts for the other end of the micrometer. Some springs, a thrust bearing and the end cap. I was experimenting with different springs as I did not know how heavy they need to be. The combination I have seems to be pretty good. The long spring goes in a hole drilled in the end of the front bar and presses against the rear end of the cap. There is a 5/16" steel ball bearing in the hole in the bar for the spring to seat against. this greatly reduces any friction for rotation of the bar. The second spring is a heavier spring and seats between the end of the bar and the thrust bearing in the end of the cap. This eliminates any friction here also. With this set up the micrometer works extremely smooth and effortlessly. I can over come the springs, but it takes both hands. There is a good bit of pressure to keep the tool against the grinding wheel. One advantage to this arrangement , is the tool travel towards the stone is a solid stop. Any give to over come the spring would move the tool AWAY from the grinding wheel, But that won't happen as the grinding force is light. This machine is not meant to do heavy grinding.
This is the end cap installed with the springs and bearings. I will make a print to match this setup. I started out building a Bonelle grinder with a few of the Quorn features, but a while back I abandoned that plan and have been building what I want as I go Because the Bonelle had some short comings and the Quorn had a lot of short comings. I guess this is why no two are ever alike.
I also engraved the 360 degree markings on the tool holder index wheel and stamped the numbers. the numbers are stamped 0 - 10 - 20 - 30 - 40- 40 - 30 - 20 - 10 - 0. This sequence is repeated in every 90 degree quadrant. In reading what I found on the Quorn and Bonelle, This has to something to do with indexing tools to sharpen. I personally was just going to number 0 - 360, but still can later if desired. ( I would just machine the numbers off and re stamp them).
When I mark the rotary base table, I will mark it every 5 degrees as it is only 3 inches in diameter. This one was 4 inches diameter and the lines are close. My eyes aren't that good.
- Joined
- Jan 25, 2015
- Messages
- 2,558
Best wishes with med issues.
Makes me grateful to be 50 and still have everything functioning mostly normal. Just a few aches and pains like buldged discs, etc.
You do great work for someone with limited mobility and limited time on your feet!
Makes me grateful to be 50 and still have everything functioning mostly normal. Just a few aches and pains like buldged discs, etc.
You do great work for someone with limited mobility and limited time on your feet!
yea, it ain't easy, but keeping busy keeps me going. I sit on a stool in the shop most of the time and stuff is in easy reach when your shop ain't no bigger than a closet. If I have to quit machining, they might as well take me out back and shoot me.
I sat in my wheel chair for a year and it drove me crazy. I just have to be doing something. Getting the morphine pump implanted gave me my life back. I can function a lot better.
It is ok, there are a few errors but nothing terrible. I am learning more as I go about this marking dials. I finally got engraving lines down, but still struggle a little on stamping numbers. I was going along and the numbers looked perfect and suddenly the next two numbers were off. I got all bent out of shape cause I just messed up my dial (a little) I figured out that the stamping blow from the hammer causes the part to come loose on the chuck and move. So , the trick is to check every few stamps and make sure the part is still tight. This is a learn as you do experience for me and once I get all these little tricks figured out, I should be getting much better results. I am also making notes on how far to turn the dial to stamp double numbers. It varies with the size stamp. the 1/8" stamp, I turn the dial 2 degrees before the mark for the first stamp and 2 degrees after for the second stamp. this gives good spacing and consistency. BUT that also varies with dial size to some extent ( you can't stamp 1/8" numbers on a 1 inch dial. for example). I have a different set of parameters for 1/16" numbers. I will have it figured out by the time I have all my dials stamped
