# Knurling attachment question (scissor or clamp type?)



## ARC-170 (Sep 17, 2020)

I have an older Atlas Craftsman lathe (101.07403 made in 1944) and am not comfortable using the usual knurler that is pressed from the side. It puts too much pressure on the bearings and I'm afraid it will push the part off the center if I try to get a deep knurl. So, I'd like to get a different style. 
There are two: scissor and clamp. Any preference? Any brand I should look at? They all seem to be the same one sold by different vendors at different prices.


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## Aukai (Sep 17, 2020)

Eagle Rock, look down the page K1-44








						Hand Knurling Tools | Knurling Tools – Form Type | Eagle Rock Technologies, Inc.
					

Place your order for hand knurling tools with EAGLE ROCK TECHNOLOGIES INC. Let us show you which hand knurler is best for your upcoming project's needs.




					www.eaglerockonline.com


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## darkzero (Sep 17, 2020)

Both work well & are far better than bump style knurlers for the reason you mentioned. IMHO, generally clamp style is lighter duty than scissor but that's not a bad thing if you don't have a need to knurl tougher materials.

The scissor knurlers you commonly see are copies of the Eaglerock K1-201. Well I'm not sure if Eaglerock is actually the original designer of that tool but they make the quality one. The import clones may all look the same but some are not as good as the others.

The K1-44 that Mike linked above is the heavy duty version and like usual when something is heavy duty it costs a lot more.


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## mikey (Sep 17, 2020)

darkzero said:


> The K1-44 that Mike linked above is the heavy duty version and like usual when something is heavy duty it costs a lot more.



Yup, heavier duty, costs more, works gooder so another vote for the Eagle Rock K1-44.


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## mickri (Sep 17, 2020)

For the first time last week I used the old standby atlas/craftsman knurling tool that came with my lathe.  I had read that you needed to apply a lot of force to get it to knurl something.  Being the first time and not having any idea of what I was doing I tried different amounts of force to see what would happen.  It didn't seem like applying a lot of force or only a light pressure made any difference on 1018 steel.  I settled on a medium amount of force and let it spin for several minutes.  As it spun I could see the knurl getting more distinct.  I stopped when it looked good to me.  This was my one and only time knurling something.  So best rely on the people who actually know what they are doing.

You can make one instead of buying if cost is a factor.  https://www.hobby-machinist.com/threads/toms-techniques-knurler.86040/#post-767985


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## savarin (Sep 17, 2020)

Make one of these, a most excellent bit of kit.
You dont need a mill if you do not have one. (I dont)
The amount of pressure it applies is huge, I knurl a lot of stainless and its perfect .
One caveat, make sure the roller pins are hardened else they wear out pretty fast. Dont ask me how I know.








						Camjack Knurler
					

Okay, guys. A couple of months ago, I mentioned a Project-in-Waiting  that I called a Camjack Knurler. When you invent something, you're  allowed to make up words, too. It came about because I had checked out  several sites on clamp knurlers. Most seem to use a 6 mm threaded shaft  to apply...




					www.hobby-machinist.com


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## ttabbal (Sep 17, 2020)

I actually locked up the spindle with the camjack. I only have a thumb screw on it, but it has tons of pressure. I would like to get better wheels and hardened axles.


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## dewbane (Sep 18, 2020)

I have a cheap scissor type from Amazon that cost about $40, and included three sets of knurls. As delivered, the knurls were held in place with pins that had a slot for some kind of oddball spring clip. I ditched those and machined a new retaining system that features nylon lock nuts.

I can't say I have a high degree of confidence in the quality of the tool. I'm pretty much expecting every time I use it to be the last time this flimsy pile of junk will work. Having said that, I've actually used it to run a lot of knurls, and I've done brass, aluminum, and mild steel. I've probably run about 6-8' of knurls with this cheap pile of junk, all told. I guess I got my money out of it. It's definitely waaaaay better than the standard push from the side kind.

Now that you mention it, knurling is one of those things about owning a lathe that makes me hap hap happy. I knurl everything. I'd knurl your grandmother's kitchen sink if I could figure out how. I'd knurl your momma! I'd probably even knurl you!


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## mikey (Sep 18, 2020)

ttabbal said:


> I actually locked up the spindle with the camjack. I only have a thumb screw on it, but it has tons of pressure. I would like to get better wheels and hardened axles.



Look for Form Rol or Accu-trak knurls on ebay. Both companies also sell cobalt pins.


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## tonydi (Sep 18, 2020)

I made my own scissors-type tool and it works pretty well on my mini-lathe.  But I saw another thread here about one documented on Tom's Techniques website that seems like an even better design. I'll be making that one when time allows, based on the drawings Tom has posted on his site.  Here's the link to that thread.


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## Aukai (Sep 18, 2020)

We haven't talked about pitches yet either.....


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## darkzero (Sep 18, 2020)

Aukai said:


> We haven't talked about pitches yet either.....



That's a closely guarded secret & it's bad juju to talk about it.


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## Aukai (Sep 18, 2020)




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## darkzero (Sep 18, 2020)

Aukai said:


>





I'm not an expert on knurling so whatever I say may be total kaka. As a hobbyist, I think knurling pitches are a personal preference. In general, use finer pitches as the workpiece diameter gets smaller. Like a coarser pitch knurl will look funny on a small diameter & vice versa. Well funny as in not what you commonly see.

However one may actually want that type of look. With that said, cosmetics can play a big part in knurling. Knurling of course is usually functional but a poorly formed knurl, double tracked knurl, or a knurl pattern that is crooked, can make a nice part look not so nice. Kind of like a part that has no chamfers making it look unfinished.

But if you use a finer pitch on a larger diameter, if it's a diamond pattern knurl that you want fully formed, it won't be so harsh on the hands if used as a handle or knob. So again, it's personal preference most of the time IMO. There are times when parts needs to be a certain pitch for functional reasons, like grip for press fits for example. You wouldn't want the knurling on a wheel stud to be too fine. Needs to be coaser to provide bite so that the wheel stud won't spin but not too coarse that it won't be able to bite into the hub.

I hope the knurling gods don't punish me. I won't ever do it again. Just like I ain't ever taking a rock home from HI.


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## mikey (Sep 18, 2020)

darkzero said:


> ... Just like I ain't ever taking a rock home from HI.



You do realize that us locals made that superstition up, right? Otherwise, everyone who visits the islands would be taking home a souvenir and the islands would be 3 feet tall!   

Otherwise, I agree with what you said because you are probably one of the most talented knurlers on this forum!


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## darkzero (Sep 18, 2020)

mikey said:


> You do realize that us locals made that superstition up, right? Otherwise, everyone who visits the islands would be taking home a souvenir and the islands would be 3 feet tall!
> 
> Otherwise, I agree with what you said because you are probably one of the most talented knurlers on this forum!



Haha, really? But but, I've heard the stories!   Well I'm not really superstitious, I just makes jokes about being so sometimes, but I still wouldn't risk taking one home! 

Ah gee, Mike, thank you. I never though so but that means a lot coming from you!


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## FOMOGO (Sep 18, 2020)

Not to derail the thread, but has anyone ever tried knurling a piston? I have a 4" diameter compressor piston I would like to knurl for an oversize bore. Thanks, Mike


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## ttabbal (Sep 18, 2020)

mikey said:


> Look for Form Rol or Accu-trak knurls on ebay. Both companies also sell cobalt pins.




Good idea, thanks! I don't see any now, but I'll keep an eye out. Out of curiosity, would round HSS work well? I could grind a spot to retain them. Sounds like the wheels are HSS, so similar hardness might be an issue.


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## mikey (Sep 18, 2020)

ttabbal said:


> Good idea, thanks! I don't see any now, but I'll keep an eye out. Out of curiosity, would round HSS work well? I could grind a spot to retain them. Sounds like the wheels are HSS, so similar hardness might be an issue.



HSS drill blanks seem to work okay for me and you can get them very close to the size you need. I have no idea if they will work in your knurler, though.


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## ARC-170 (Sep 20, 2020)

The K1-201 is $260 (Amazon) for those of you following along. Too much for me at this time. The $40 imitation might work just fine for my needs. They all seem to be the exact same one sold by different sellers for varying prices.

Making one is an option. The Tom's Techniques one looks cool, but it limits the diameter that can be knurled. I can't make it much bigger since my mill jaws only open to 3". However, most scissor knurlers go up to 2-1/4" so maybe that's not even an issue.
I'm not sure I understand the camjack knurler; it seems to have unneeded pieces. Specifically, the top piece that is activated by the 1/4-20 jack screw. Seems like you could just have two arms with knurlers in them that are squeezed together by the bigger screw. What am I missing?


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## mickri (Sep 20, 2020)

Did a search online for DIY knurling tool and found this.  https://www.hobby-machinist.com/threads/knurling-tool.15151/#post-117927.  There were lots of pictures of knurling tools that people had made.


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## savarin (Sep 20, 2020)

The amount of pressure that top piece applies to the two arms with just finger tightness..
If your knurls are not tracking correctly then a quick twist applies so much pressure they just slip into alignment.
I never calculate the work dia when knurling, if they double track then I just apply more pressure and bingo, now they track.


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## ARC-170 (Sep 21, 2020)

mickri said:


> Did a search online for DIY knurling tool and found this.  https://www.hobby-machinist.com/threads/knurling-tool.15151/#post-117927.  There were lots of pictures of knurling tools that people had made.



Thanks! I like the Kant-Twist clamp idea. 

Questions:

1. I'd have to drill out the rivets holding the clamp pads to the jaws and then use drill rod as an axle; that would be able to withstand the pressure. But, how would I hold the axles in place? Light press fit? I can't machine a groove for a lock ring in the pin since the material is too hard.

2. What about a bolt thru a steel bushing/axle? The bushing/axle is wider than the jaws by a few thousands, allowing the nut to be tight, but rotate. See attached drawing. The gaps between parts are exaggerated. Of course, there's the issue of being able to withstand the clamping force.



3. Would a steel pin with grooves for lock rings work? This is for occasional hobby use, not production. I could lube it when I use it.

4. What about a rivet thru a bushing/axle? The wheel rides on the bushing/axle, not the rivet.


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## mickri (Sep 21, 2020)

I think that all of your ideas might work.  Another possibility is to use push nuts on the pins.  Don't laugh too hard.  On my 3x6 bandsaw the guide rollers are held in place by tiny C clips.  One would not stay in place and the roller kept sliding down its post.  I had the same problem with no way to machine the hardened post.  As an interim solution I put a push nut on it.  It's been over a year and the push nut is looking more permanent all the time.  I do have to periodically re seat the push nut.  I am thinking of adding a push washer followed by the push nut. 

Something else that might work is to use a SS clevis pin.  You can get them in any marine store.


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## ttabbal (Sep 22, 2020)

You could use a cutoff wheel in a dremel to cut a groove for retaining the axle. You would probably need a tool post holder for it to get one all the way around the pin, but you could do one side and use a washer or similar with a threaded hole to the side to retain the pin.


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