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Knurling 101?
- Thread starter Janderso
- Start date
There is another type of knurling tool that does actually cut the knurl, has types for straight and diamond knurl; I think they are Swiss made; very little pressure involved, they are fed to depth at the start and fed axially for the cut.
This is not rocket surgery.
Place stock in work holding device, chuck, collet or between centers. Place tool in holder and knurl.
If cross pattern knurling run the tool into the work as fast as possible with the required force to make the knurl in one shot, do not be shy here.
A cross pattern requires 2 tools so a scissor type holder makes much sense. In 30 years of knurling I have never once considered diameter/knurl pitch to be important, as mentioned above a tapered part should knurl just fine, have never done it but may give it a try this week just for fun.
I have never used a cut knurl but we do have one so may try that as well.
Place stock in work holding device, chuck, collet or between centers. Place tool in holder and knurl.
If cross pattern knurling run the tool into the work as fast as possible with the required force to make the knurl in one shot, do not be shy here.
A cross pattern requires 2 tools so a scissor type holder makes much sense. In 30 years of knurling I have never once considered diameter/knurl pitch to be important, as mentioned above a tapered part should knurl just fine, have never done it but may give it a try this week just for fun.
I have never used a cut knurl but we do have one so may try that as well.
Some folks get all excited about using math to determine the proper material OD for doing the knurl. Well, maybe yes and maybe no on the math. I do get the math concern, but for me, I have NEVER done any math and my knurl jobs come out just fine. I use the Aloris scissor type. I come in onto the edge with full depth. I make the knurl as quick as I can, I do not hang around. Hanging around imbeds crap into the knurl. I get in and get out quickly…Dave
Try to knurl harder materials or anything that work hardens easily & you'll quickly learn that you need the math. With soft materials, like most everyone has experienced, just mash on it more & usually you'll fix any double tracking. And with cut knurlers, math is important if you want repeatable results.
I found this link & made a simple spreadsheet based on their guidelines.
https://accu-trak.com/technicalinfo/blank_diameter_selection.html
Just a few inputs (red numbers) & it spits out optimal starting diameter, boom done. This dramatically improved my prior hit & miss results, especially finer pitch & larger diameter combos. For sure there are still variables in the process like material & squeeze depth which is a feel thing, but this eliminated the inconsistency. I think some combinations 'work' just because of lucky combinations. But change one or the other or both & that will be the crappy knurl that will refuse to look good. I liken this to intermeshing gears where gear pitch & center distances are... well... kind of important. Good luck & happy knurling!
https://accu-trak.com/technicalinfo/blank_diameter_selection.html
Just a few inputs (red numbers) & it spits out optimal starting diameter, boom done. This dramatically improved my prior hit & miss results, especially finer pitch & larger diameter combos. For sure there are still variables in the process like material & squeeze depth which is a feel thing, but this eliminated the inconsistency. I think some combinations 'work' just because of lucky combinations. But change one or the other or both & that will be the crappy knurl that will refuse to look good. I liken this to intermeshing gears where gear pitch & center distances are... well... kind of important. Good luck & happy knurling!
John Stevenson once form knurled a taper to demonstrate how much bull is talked about diameter having to match pitch.
Joe Pie's video shows that the assumption that OD must relate to pitch is wrong for formed knurling, if you know how to knurl.
I've never had a formed knurl track incorrectly since I learned that straight in hard with plenty of lube works every time and *****-footing around leads to belief in calculated diameters.
Joe Pie's video shows that the assumption that OD must relate to pitch is wrong for formed knurling, if you know how to knurl.
I've never had a formed knurl track incorrectly since I learned that straight in hard with plenty of lube works every time and *****-footing around leads to belief in calculated diameters.
I'm just a hobbyist so what do I know. My hunch is what's happening behind the scenes is the stock diameter is being altered by relative feel. Light pressure deforms the stock less (but can show up as incomplete knurl). Heavy over-pressure distorts the stock more (but can show up as galled knurls). As long as the material + knurl type + setup rigidity ++ is amenable to this variation then some sort of pattern will emerge. Some people view knurling as 'if it didn't double track then its awesome'. But under any magnification it may well look like sh*t.
Every time you pick up a micrometer you are doing 'math' unless the line happens to coincide with zero every time, so I guess I don't see the big deal. Why not stack the cards in your favour by turning it to a specific diameter? If it doesn't work you haven't lost anything over 'straight in hard' to whatever diameter presents itself. I mean you're going to be turning it down to 'some' diameter anyways just to ensure its circular right? The bottom line is if you're happy, then so am I.
Every time you pick up a micrometer you are doing 'math' unless the line happens to coincide with zero every time, so I guess I don't see the big deal. Why not stack the cards in your favour by turning it to a specific diameter? If it doesn't work you haven't lost anything over 'straight in hard' to whatever diameter presents itself. I mean you're going to be turning it down to 'some' diameter anyways just to ensure its circular right? The bottom line is if you're happy, then so am I.
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Why not stack the cards in your favour by turning it to a specific diameter?
Why? Because it's unnecessary?
OTOH if you have so much time and so little you want to do with it that you can waste time at every opportunity Why Not? It saves you learning how to engage the tooling in a way which just works regardless of OD ;-)
If you want high quality, predictable, reproducible production quality knurling you would use Cut Knurling, try it. If you can bring yourself to fork out for the tooling.
With Cut Knurling you can produce a light knurl on plastic (10% area or less cut) with sharp edges which give a comfortable feel and excellent grip, furthermore it looks like a product you'd buy.
Interesting thread.
Does anyone know where I can buy narrow knurling wheels with fine patterns? The wheels I need are to be a 1/16" wide. I have found Youtubes of how to make them with a mill but I don't have a mill and I'm still at the beginning of my learning to use a lathe.
Any suggestions welcome.
Does anyone know where I can buy narrow knurling wheels with fine patterns? The wheels I need are to be a 1/16" wide. I have found Youtubes of how to make them with a mill but I don't have a mill and I'm still at the beginning of my learning to use a lathe.
Any suggestions welcome.