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KJ1I
11-13-2013, 01:10 PM
I put this together for a project I'm about to start. I didn't like the look of those I found. Feel free to download.

http://www.redoakmodels.com/Downloads/Knurling_Charts.pdf

mklotz
11-13-2013, 02:30 PM
Couldn't all those pages of numbers be replaced by a simple formula?

KJ1I
11-13-2013, 03:16 PM
Couldn't all those pages of numbers be replaced by a simple formula?

Certainly. That's how they were generated. But I don't have a computer in the shop and I would far rather get dirt, oil, cutting fluid, etc. on a piece of paper than my computer or tablet. And I'm not about to sit down and perform the calculation by hand as I start the lathe.

John Stevenson
11-13-2013, 03:21 PM
Couldn't you just knurl the shaft as people have been doing for centuries ?

EddyCurr
11-13-2013, 03:36 PM
Nothing wrong with wanting the optimum result
in return for going to the effort.

.

KJ1I
11-13-2013, 04:06 PM
Couldn't you just knurl the shaft as people have been doing for centuries ?

Tried that. The day the knurling tool arrived, I tried to put a nice knurl on some stock to use as thumb screws. Turned out pretty crappy. Remember, its been nearly 30 years since I've spent much time in a metal shop. So I went back to the books and found the stock diameter makes a difference. Duh. Turned the stock down to the right size and ended up with the kind of knurl I expected from myself.

mklotz
11-13-2013, 05:22 PM
Certainly. That's how they were generated. But I don't have a computer in the shop and I would far rather get dirt, oil, cutting fluid, etc. on a piece of paper than my computer or tablet. And I'm not about to sit down and perform the calculation by hand as I start the lathe.

One can buy scientific calculators for a dollar in the dollar store. I've programmed that equation (see my website) and it's a doodle to do on a calculator - no computer required.

boaterri
11-13-2013, 05:28 PM
Table downloaded, Thanks!

Rick

dp
11-13-2013, 05:30 PM
In 2004 John Stevenson introduced this thread on knurls. The images were lost but found again on a way-back machine.

http://bbs.homeshopmachinist.net/threads/11926-Cut-knurling-tools

The images are here: http://thevirtualbarandgrill.com/stevenson/files/phpshow.php

One of the images shows a single shaft turned in steps to various diameters and then knurled. Very interesting. The knurling tool is similar in function to the cut knurl tool that Michael Ward made in the HSM magazine last year.

DR
11-13-2013, 07:51 PM
KJ1I,

What type of knurling tool did you buy?

I ask because I've been doing production knurling for years with various tools with opposed knurls, similar in action to the common scissor type. I never concern myself with the blank diameter, except when the knurling causes the finished diameter to be not to print. Prints very seldom specify a close tolerance on knurled diameters anyway.

I turn the blank to a diameter an educated guess will result in the correct knurled diameter. If the finished diameter is too big or small the blank diameter is adjusted accordingly. I can't recall ever having a problem knurl due to a blank diameter being wrong. Knurling problems have just never been an issue.

Richard P Wilson
11-13-2013, 08:09 PM
Never knew there was a problem. I've always just fed the knurler onto the work, and got a knurl I was happy with, never worried about diameter, pitch etc. Maybe I just have low standards.

Richard

KJ1I
11-13-2013, 08:51 PM
KJ1I,

What type of knurling tool did you buy?

The knurling tool is an import scissors type. I don't remember if it came from Enco or VME. I spent more time trying to get it set up than actually running the knurl. I ran it down the desired length then ran in reverse back to the start. Crank the nut down "some" and repeat. Knurls ended up kinda "crunched" or banged over. Stock was 1" HRS scrap, exact composition unknown. Before knurling, I mounted it between centers and took a couple of cleanup passes until the entire surface was bright. Didn't think to mike the diameter when that step was done.

Royldean
11-13-2013, 09:10 PM
no computer required.

I'm nitpicking here, but a calculator IS a computer.

DR
11-13-2013, 10:13 PM
The knurling tool is an import scissors type. I don't remember if it came from Enco or VME. I spent more time trying to get it set up than actually running the knurl. I ran it down the desired length then ran in reverse back to the start. Crank the nut down "some" and repeat. Knurls ended up kinda "crunched" or banged over. Stock was 1" HRS scrap, exact composition unknown. Before knurling, I mounted it between centers and took a couple of cleanup passes until the entire surface was bright. Didn't think to mike the diameter when that step was done.

My guess is repeating over the knurl could be a problem. We NEVER run back over a knurl. The knurl is done in one pass and the tool pulled off the work as fast as possible.

When we knurl from the side on the CNC lathe the knurl is advanced over the work to the work center and back off rapidly so the part makes only a few revolutions under the knurl wheels. When knurling from the end the knurl wheels have to backed off over the knurled area, again as fast as possible.

We also knurl dry. There's some debate on that issue. The company I've bought knurl rolls from contends it makes no difference wet or dry.

jep24601
11-14-2013, 08:42 AM
The are many published articles describing the calculations necessary to achieve a clean knurl. Dorian publishes a nice PDF which includes the depth of cut for the different knurl types. Of course for the purpose for which a knurl is intended a rough knurl is as good as a clean knurl.

bewards
11-14-2013, 01:02 PM
thanks for the chart!



bedwards

bobw53
11-14-2013, 01:41 PM
Dorian publishes a nice PDF which includes the depth of cut for the different knurl types.

Here is a cool Excel spreadsheet for knurling, speeds, feeds, diameters, depths, different materials the whole nine. I'm not sure if its Dorian's or not.
The link is in red toward the bottom of the page.

http://www.innovativetoolsales.com/dorian_knurling.htm

Mike Amick
11-14-2013, 02:21 PM
Thanks .. bookmarked that. But to be honest, someone would have to set me down to
explain what the different parts of the formula mean.

Have to think that for some people, like me, Kevin's sheet are quite useful ..

Thanks Kev
Mike