A Straddle Knurler for the Sherline Lathe

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Grinderman said:
Could you explain this statement? I thought you were using 1/4” wide wheels in a 1/4” wide slot in the arms.
Thanks
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OOOHHH, MAJOR MISTAKE!!

I didn't catch that but this mistake has been sitting in this document for 15 years and I never caught it. Thanks for calling this out.

Okay, the knurls are 0.2495" wide; I measured all the wheels. The slot in the end of the arms is 0.255" wide so there is only 0.0055" of clearance in the slot, or just under 0.003" on each side of the wheel.

Thanks for paying attention, Grinderman!
 
mikey said:
OOOHHH, MAJOR MISTAKE!!

I didn't catch that but this mistake has been sitting in this document for 15 years and I never caught it. Thanks for calling this out.

Okay, the knurls are 0.2495" wide; I measured all the wheels. The slot in the end of the arms is 0.255" wide so there is only 0.0055" of clearance in the slot, or just under 0.003" on each side of the wheel.

Thanks for paying attention, Grinderman!
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Ok, thanks. The reason I asked is because the Knurls in my bump type tool are actually quite sloppy on the shaft and side clearance. Wasn’t sure if some slop was required for a good result.
 
Now that I think on it, I remember now that I pondered on this issue and decided not to worry about it because the space that is there seemed sufficient. I have not had a single time when tracking was an issue; pressure is. As long as I can apply enough pressure then tracking occurs without problems.

This raises a good point that maybe we can discuss here. My knurler is as rigid as I can make it and it is mounted really solidly when it is in place. I can't make things more rigid than this, I assure you. I have even less space in the arms for the wheels than I thought, thanks to Grinderman, and still have no issues with tracking. It seems to me that if you have matching wheels of decent quality then you should be able to make a decent knurl of the knurler is solid enough to apply sufficient pressure. There must be some space for the wheels to synchronize but apparently, not much is required. So, does this point to the need for higher quality wheels?
 
@mikey for the nut, did you thread it the whole length? Or just a section, like just shy of an inch? The pdf states it is 1-5/16" long. Most taps are only 1" long, or did you single point it? One could tap it 1" and then clearance bore it the other 5/16". So it will be a nut with a built in spacer.
 
You only need a thread that is 1-1/2 times the diameter to achieve maximum strength. For a 1/4-28 thread, that is a threaded section 3/8" long. I threaded twice that, about 3/4" of thread, with a tap. I screw cut the thread for a very good fit and it has been enough.
 
I'm pretty far along in my build of this. Just need to cut the slots for the knurls. I'm a bit stuck on what knurl I want to run. I will do exclusively long knurling along the x-axis feed so I think a convex knurl is the way to go? In the catalog the EPV series is 1/2 in diameter and has the 3/16 shaft but is only 3/16 wide vs. 1/4 width. I already drilled my 3/16 shaft holes and have the drill rod but I have not cut my arm slots yet. @mikey do you see any issues with going this way as long as I cut my slots to fit those EPV knurls?
 
I use the 1/4" wide EQ series myself. With beveled edges, this leaves a 1/8" wide pattern surface to do the work. I do not know if Form Rol makes a convex knurl in this diameter; you'll have to check with them. Accu-Trak might make one in this size, not sure.
 
mikey said:
I use the 1/4" wide EQ series myself. With beveled edges, this leaves a 1/8" wide pattern surface to do the work. I do not know if Form Rol makes a convex knurl in this diameter; you'll have to check with them. Accu-Trak might make one in this size, not sure.
Click to expand...
Maybe it’s just me but when I go on the Form Rol site and click on the EQ series Knurls I get nothing.
 
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