Knurling tool build

My plan to hold the knurls is to use a shoulder bolt with 1/4" shoulder. The head is 3/16" high. I think I can counterbore it 1/8" deep. Then I will have only 1/16" head showing or I can machine that off.
For the center pivot, I plan to machine a bushing 1/2" OD with a lip on the outside. This may be brass? I will center drill this and use a 5/16" screw into rectangular bar that will be held in the AXA tool holder.
Any better ideas welcome.
Robert
 
rwm said:
My plan to hold the knurls is to use a shoulder bolt with 1/4" shoulder.
Click to expand...

On knurlers I've built the axle for the knurl wheel takes a lot of abuse. I've built with O-1 tool steel which was then hardened and it was not good enough for the pressures of knurling. All mine now have hss axles.
the one for my manual lathe has small button head screws in the knurler body that retain the axle. They are in parallel with the axle, just off to the side so the head of the screw keeps the axle in.
The two for my cnc lathe have a groove ground in the hss and a single 4-40 flat head screw each retaining them at 90 deg or up and down where axles are horizontal.

When the axle is to soft and wears from knurling pressure it is then a problem to remove as metal is displaced and a groove ground into the axle.
 
Wow, that is good to know. Maybe I should scrap my plan. How about using 1/4 drill shanks? Is the shank of an HSS drill hard? What about carbide?
Robert
 
rwm said:
Wow, that is good to know. Maybe I should scrap my plan. How about using 1/4 drill shanks? Is the shank of an HSS drill hard? What about carbide?
Click to expand...

A hss drill shank would be fine. But hss blanks are available.
Carbide would work great, but it's so hard that cutting it to length can be a pain. The hss will need to be cut abrasively (grinder cut off).
Deffinatly don't scrap your plan. It looks like a great tool!

HSS blanks: hope these links work.

RDX High Speed Ground Round Tool Bits

www.wttool.com www.wttool.com

 
I will plan to use an HSS axle of some type. I think I will not drill one of the axle holes all the way through and them use a small screw to hold the axle in place. I have some 10mm steel on order as well as some 5/8 keystock for the holder.
Robert
 
Once you get it all sorted out why not upload the CAD files of the parts you worked on. That way someone with CAD/CAM software and a mill could load them in the system, make some G-Code with a post for their machine and make the parts.

I hope one or more do that with this simple project and post pics of the results!

Would be a nice way to share the work and let someone show off their CNC milling capabilities...
 
I plan to upload prints if this is successful.
Robert

Yes, I could make the CAD file available.
R
 
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I revised the drawing to get a better angle for the tensioning screw:

1584154852137.png

1584155526907.png

I think this is near final design version. Any ideas?
Robert
 
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rwm said:
I think this is near final design version. Any ideas?
Robert
Click to expand...

Maybe it's just the way the pictures look, but it appears like the original had a longer distance from the pivot to the pressure bolt fitting.
Where as your latest appears like the longer distance is from the pivot to the knurl wheel. That would give the pressure screw much less leverage.
Maybe it just appears that way to me. And maybe it would make little difference.

Also wanted to mention that when cutting hss blanks(or carbide) I just score them with a dremel cutoff wheel and then put them in a vise and break it off with a hammer. Saves time , brakes pretty cleanly, and avoids getting the piece so hot.
 
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