Adventures in knurling.

Ray C said:
David and Mikey...
Nice work there to the both of you!
The clamp-style tools are indeed a big step forward but, you'll jump a light year ahead by using precision wheels. Darkzero (Will) on this list turned me on to the ones from this place http://accu-trak.com/company_profile.html and I'm sold! Try the convex type which have an apropriately contoured spiral on the radiused edges. It's designed so that as you clamp into the work, the lines stay straight as the effective cutting diameter decreases. -Cat's Meow!
The cheapo knurl wheels that come with your basic $30 holder tend to have very uneven thread spacing. I even had a few where the center holes were not centered. -Causes all kinds of problems.
Ray
Click to expand...

OK I have the accutrak site up and have no clue what knurl wheels to buy. For my Sherline. I will want inch wheels so would I want the EPV series and would a 90 degree 21 TPI work OK? Thanks in advance as this is on my to-do list next.
BB
 
First, BB, welcome to the forum.

Which wheels you get depends on the type of knurling tool you use and the kind of knurling you intend to do with it. The convex knurls are used for axial running, meaning you start knurling and run the tool down the work piece to make a longer knurl pattern. They will not work well for short knurls. While the Accu Trak site says the beveled edged knurls are not as good as their convex knurls for axial running I have used Form-Rol beveled knurls for years and have had no issues with them. I am sure I would run the coaxials in a production environment but not in a hobby shop unless I need to knurl long sections. Still may try them someday just to see how they work.

The Sherline lathe works well for knurling within its performance envelope. You need to size your tool to the lathe and the work. The OEM Sherline tool is okay but cumbersome to use and is limited to knurling a piece up to about an inch, I think. A scissors type tool works far better, is easier to use, and mine can handle up to a 2" diameter work piece. I use Form Rol EQ series knurls; these are 1/4" wide with beveled edges that take up 1/16" on each side, so the working part of the knurl is only 1/8" wide. Yes, these are small knurls but they work very well and have a very good work life. They will do short runs and axial runs. The OEM Sherline tool uses Form Rol knurls as well.

My suggestion is to buy or build a knurling tool to accept the knurls you intend to use.
 
Mikey thanks. That's what I needed to know especially the longer knurls thing. Thought I had to do that in steps. Knurl, move it over the knurl again. I have copied your tool design and will be making my own holder.

Here's the dumb-question-of-the-day... do you use knurling tool while manually turning the lathe or at a very slow speed? Also are the dies clamped at the top center or close to it?

Thanks for the tip about dies. And sharing your experience. :)
BB
 
Knurling on the Sherline lathe is done at relatively low speeds - 500 RPM for a 1/2" piece, for example. It varies with the material type and size and also how the machine responds to the load. You'll get a feel for it once you try it.

The scissors knurler is set up so that the center of the tool is at the centerline of the lathe. The tool arms can move up and down and will sort of self-center.

You can find more info on this knurler here: http://nsa.kpu-m.ac.jp/gijutu/kousaku/easyweb.easynet.co.uk/chrish/homepge2.htm

Mine is based on Heapy's design but sized for my lathe. Anyway, good luck!
 
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