View Full Version : Knurling sizes

02-08-2014, 04:25 PM
So spent the last couple days reading/watching knurling, enough to think it a worthwhile project to add to the growing list.

A basic question regarding the sizes of the knurling wheels.
Is there advantage or disadvantage within the various sizes of wheels? Diameter but I suppose the width could be another factor.
Related, are the various designs scalable?
Leaning towards the SPI version Tom Griffin used on a recent video and based on current comments it sounds as if he is planning to do a project build, so I may just wait for that...

My thought is to build to suit a size of knurl wheel I know is currently available but it seems like some sizes have more choices of pattern.
As well, there a a few types (MSC catalog lists three) and quite a few different series. I can understand if a given series is for a particular holder from a specific maker but is there a reason one could not adapt a holder built from scratch to accommodate any particular series?

02-10-2014, 01:07 PM
If you make your holder to accommodate the wider knurls, you can add some axle spacers to let you use narrower ones too.

I don't know if the axle hole in the bugger knurls is larger... if so, you might need to make a few sets of axles.

02-10-2014, 01:11 PM
You have to take into consideration that the wider the knurl the more force it is going to take to displace the material. If you have a small tool room lathe that can be tough on the cross slide screw as well as the rest of the saddle.
I angle the knurl slightly so only the edge bites in first, that way it requires less force to get results.


02-10-2014, 01:21 PM
which edge, leading or trailing?

02-10-2014, 01:25 PM
that can be tough on the cross slide screw as well as the rest of the saddle.

Indeed. I'd definitely recommend a clamp or scissor type as opposed to bump or push type.

02-10-2014, 01:28 PM
I always use the trailing edge. It's easier to sink the edge in than the entire face of the knurl. I never tried the reverse I think it would tend to plow.


02-10-2014, 01:37 PM
I only use the scissor type to keep the wear and tear off the lead screw. I have some knurls that are crowned (bigger in the middle) that work really well. It's more convenient to stick to one standard size of knurling wheel, but you can easily make your own knurling tools if you want to fit more than one size economically.

Jaakko Fagerlund
02-10-2014, 02:06 PM
which edge, leading or trailing?
Trailing edge, so the tool basically cuts deeper and deeper as it is advanced.

But if at all possible, make or use a cut knurler, it is really 1000 % better for you, the machine and the workpieces.

02-10-2014, 09:18 PM
I remember seeing something on the cutting knurler posted a while back, it was a bit involved.


Rich Carlstedt
02-10-2014, 09:58 PM
Making a Knurl holder is very simple if you don't have the bucks.
Get a piece of angle iron, say 2 x2 and maybe 3 inches long.
On the base leg drill a hole for a clamp screw (short stove bolt ?) to your tool slide.
On the vertical leg , which it next to your round work piece ( Lathe center axis) mark the center height of the work on the vertical leg
This would be the same height as your tool bit is at for normal work. Remove the angle, and mill a vertical slot centered on the work height mark.
So lets say the knurl is 3/4 in diameter and 1/2" wide. so the slot is made a few thou wider than 1/2" and about 3/8" above and below the height mark. Now get a short piece of drill rod ( 3"?) to match the knurl bore and drill/tap two holes in the angle and mount the knurl on the shaft and fasten the shaft on the work side of the angle, on the compound. The Knurl will be guided by the slot sides and the drill rod axle pushes against the angle when under load, so the screws see little force.

Learn the various knurl applications. Do not believe any one approach is the "only" way to do it.
Every one has their pet methods , because they perfect "that" approach. You may find a multiple of workable attacks to your job.
Know that each Knurl has an ideal diameter to work with for that pitch AND that material . Some metals are very ductile and flow into form readily, and others actually cause metal particles to be removed to get a good knurl

One thing most folks don't realize is that Knurl wheels can form wondrous patterns when the pitch of the wheel is used carefully.
Here is a photo of work done by a stock Aloris Knurl wheel, which is probably a 10 pitch (.100 ) diamond pattern.
The knurled cap is only .180 " in diameter and yet has a perfect knurl. This is because the "big" knurl wheel made multiple starts (5?)
so the wheel returned to its first cut , maybe 5 turns later. To get this pattern, I had to remove .001' one or two times and then found the magic size. The depth is only about .002

http://i273.photobucket.com/albums/jj220/StationarySteam/MonitorTricockValve_zpsd3817171.jpg (http://s273.photobucket.com/user/StationarySteam/media/MonitorTricockValve_zpsd3817171.jpg.html)


02-11-2014, 12:58 PM
i always thought the knurl neded to "bite" to get the right pattern. i usually touch off, bring it in 0.2 mm, engage power fedd and let it run.

rich, i read you first paragraph seven times, but stii wonder how that works (picture)?

Rich Carlstedt
02-13-2014, 05:35 PM
dian, yes , the bite is important to start, and what I did was determine the diameter needed to get 5 starts , with the 6th repeating over again.

Here is the WORLDS SIMPLEST Knurling tool holder
I have a straight knurl tool mounted in it, and it only took a few minutes to make

http://i273.photobucket.com/albums/jj220/StationarySteam/Shop%20Tools/P2130155_zpsed40a967.jpg (http://s273.photobucket.com/user/StationarySteam/media/Shop%20Tools/P2130155_zpsed40a967.jpg.html)

http://i273.photobucket.com/albums/jj220/StationarySteam/Shop%20Tools/P2130154_zpsd58ecb93.jpg (http://s273.photobucket.com/user/StationarySteam/media/Shop%20Tools/P2130154_zpsd58ecb93.jpg.html)


02-13-2014, 06:57 PM
I just built a clamp type knurling tool based on the design in Lautard's book. I added the knurl set (coarse, medium, and fine) to an order from Shars, and forgot to order the diagonal ones for the diamond pattern. I couldn't get the medium knurl to work at all. Repeated the calculation, re-cut the diameter to the next "magic" diameter, still wouldn't work. Did this a number of times with various start techniques and pressures. In the mean time, I ordered some stuff from Enco, and included the diagonal ones in the order. They were noticeably sharper, and I got a perfect diamond knurl on the first try.

The Shars knurl wheels seem to be quite rounded on the top of the teeth. I tried to get a picture, but I couldn't really show the shape. YMMV, but I'm staying away from the Shars knurls in the future.

02-13-2014, 09:44 PM
Thanks for all the input.

Reading more, turret lathe knurling tools are interesting all on their own...and not that far removed from the way that SPI version works (my interpretation)