# Clamp Type Knurling Tool



## cascao (Jan 10, 2018)

Made this Clamp Type Knurling Tool based on a smaller comercial item I already have. This one can be used on bigger diameters [bit over 2"], mount centered on tool post and is more robust. Screws can be tightened to remove side slope.



Test run showing welded support. 



All parts were made in a lathe. Just Facing with a 4 jaw chuck. 



3/4" by 1/4" flat bar was used for this four pieces. Two of them have central hole counterbored. In this hole a small spacer  [same wheel thickness] in mounted for rigidity.



Used 1/2" square bar to this piece. The area with holes need to have the thickness reduced to same wheel thickness.



You will need also:
* a threaded bar, M6 or 1/4".
* Two Ø1/2" bar 20mm long.
* A special knurled nut you can made.
* Two knurl wheels.
* Two 1045 pins for knurl wheels. After turning them, heat with a torch and quench in water. Test hardness with a file. Unfortunatelly didn't have any photos of them. Just make the diameter of one side slighty bigger so they mount pressed on side plates. Or use a car poppet valve stem.


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## Moper361 (Jan 10, 2018)

Nice build ,I'm thinking about making a Knurling tool on my list go ever growing items to do ,I will keep this in mind


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## brino (Jan 10, 2018)

@cascao , that is exactly what I have in mind to build! 

I already have the knurl wheels in stock and will have to check that the diameter of them will work with your dimensions.
Thanks for sharing the design.

-brino


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## middle.road (Jan 10, 2018)

brino said:


> @cascao , that is exactly what I have in mind to build!
> 
> I already have the knurl wheels in stock and will have to check that the diameter of them will work with your dimensions.
> Thanks for sharing the design.
> ...


What type/kind of wheels have you got in your stock? Would it be possible to post some pictures?
I'm discovering the differences and attributes as it were, of the various wheels I've been using.
Some have chamfered shoulders, some are 'sharp'. And then there are the imports. . .


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## brino (Jan 10, 2018)

middle.road said:


> What type/kind of wheels have you got in your stock? ................And then there are the imports.



Dan, The ones I got for my project are definitely cheap imports........
They were replacement wheels for this tool:
https://www.busybeetools.com/products/knurling-tool-no-6.html
I just went and checked my previous Busy Bee tools order to post links to them, but it appears that they do NOT sell them any more!

I will try to get some pictures.(.......feel free to poke me with a PM if I'm forgetful/lazy ;^)

However, if they turn out to be real junk, I might just buy a NOS bump style tool that my local used tool places sells, and harvest the wheels for this project. I would have done that initially, but they only recently have them in the store.

-brino


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## T. J. (Jan 10, 2018)

Nice work!  I like the 2-piece arm design, which simplifies the build process greatly.  

I am in the process of building one with 1-piece arms, which requires milling the slots.  So far, I have broken 3 end mills.   The learning curve on a milling machine is steeper than I anticipated...


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## brino (Jan 12, 2018)

middle.road said:


> What type/kind of wheels have you got in your stock? Would it be possible to post some pictures? I'm discovering the differences and attributes as it were, of the various wheels I've been using. Some have chamfered shoulders, some are 'sharp'. And then there are the imports. . .



As I mentioned above my knurling wheels were from Busy Bee tools, but they do not seem to offer them any more.

They are approx. 0.625" dia, 0.309" thick and have a 0.214" axle hole.

Here's some shots:









-brino


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## Ray C (Jan 12, 2018)

brino said:


> As I mentioned above my knurling wheels were from Busy Bee tools, but they do not seem to offer them any more.
> 
> They are approx. 0.625" dia, 0.309" thick and have a 0.214" axle hole.
> 
> ...




Here's a very good knurl tool supplier.  Top flight stuff.

https://www.accu-trak.com/index.html


Regards

Ray C.


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## middle.road (Jan 12, 2018)

Ray C said:


> Here's a very good knurl tool supplier.  Top flight stuff.
> 
> https://www.accu-trak.com/index.html
> 
> ...


AFAIK, They are the only stateside supplier left around - .
Prices are currently too steep for me. Would probably out perform the NOS I'm playing with though.


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## ddickey (Jan 12, 2018)

Wonder how hard it would be to make one of those 3 die holders?


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## Tim9 (Jan 12, 2018)

Ray C said:


> Here's a very good knurl tool supplier.  Top flight stuff.
> 
> https://www.accu-trak.com/index.html
> 
> ...


I went to that site and they mention TPI for imperial knurls. Does it really matter ? is there some significance of TPI and lead screw TPI ?  I purchased some knurls off of Ebay and kind of thought it was just a hit or miss proposition. The learning curve never ends...


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## cascao (Jan 13, 2018)

tpi or the gap between each teeth on knurl is used to calculate the diameters you can use your knurl.

is a good practice the division [(3.14*part diameter)/knurl pitch] be zero. it produce better looking knurls.

mm or inch will procuce same results.

since the pich on knurls wheels are always very fine, there a lot of diameters options we should make our parts. they vary for few 0.anything


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## Ray C (Jan 13, 2018)

cascao said:


> tpi or the gap between each teeth on knurl is used to calculate the diameters you can use your knurl.
> 
> is a good practice the division [(3.14*part diameter)/knurl pitch] be zero. it produce better looking knurls.
> 
> ...



There's a little magic when it comes to knurls and on the rare instances I need to do it, I always cut a practice piece.   Getting the numbers to line-up as mentioned above is a guideline but, I think cascao misspoke and intended to say the relation should result in an integer number -not zero.  I believe the intention was to say, the fractional portion of the result should be zero.   In theory, if the number of grooves does not align naturally with the diameter of the part, you'll have an oddball groove that does not overlay on the surface evenly.  So here's the problem.  Pi (3.141592654...) is not a natural number and it will make the numbers a little hard to come out without a fractional part.   That's OK because knurling is not an exact process....

As you clamp down on the part, the metal deforms and the diameter of the part is effectively changing.  In addition, the TPI of the knurl becomes less important and the diametral pitch becomes more important.  Given all this, even if you adjust a part diameter and knurl TPI so that circumference divided by TPI is an integer (not even, but integer such as 1, 2, 3... ) it will go out the window as soon as you start sinking the knurl into the piece.

This is the same theory as a bolt and the threaded hole it goes in.  A 1" bolt and corresponding hole do not have any physical feature that is 1 inch.

If you want ideal knurls, you're probably better off thinking about diametral pitches of both the knurl and the "imaginary" one that gets formed on the part.

All that said, the last couple times I tried to make a pretty knurl I did a couple practice pieces of different diameters.  On some, it was easier to establish and maintain a nice knurl.  Sadly, I forgot to measure which diameters worked best.  I would not be surprised if the correct way of doing this is really about determining the volume of metal that has to be displaced into the die-teeth of the knurl.  I could make such calculations if so desired... I doubt it's worth my time. 

Regards

Ray C.


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## Bob Korves (Jan 13, 2018)

What it is really about is the first revolution of the work with the knurls engaged.  You want the knurls to fall into the same grooves that were made on the first revolution, at least close enough to engage the existing grooves and not starting new ones.  I have my best luck using the formula for diameter but then engaging the work axially (from the end of the work) if possible, with a moderately light but definite cut.  If it has to be a plunge cut, I do not start by gently dialing in to the pristine part, but instead start the spindle with the knurls already engaged solidly with the work.


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## middle.road (Jan 13, 2018)

+1 to Bob's suggestion.
With the mods I'm doing to brass, copper, and aluminum tubes the diameter is fixed, can't modify them to match a formula.
I've been engaging the wheels, lathe set to Low, engage, and hope for the best. Results WILL vary. 
There's picts in my Kant-Twist Knurler Thread.


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## Ulma Doctor (Jan 13, 2018)

Nice Work cascao!!!!


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## Ray C (Jan 13, 2018)

Ulma Doctor said:


> Nice Work cascao!!!!



Yes indeed.  I like that style of knurl tool and yours is looking really good!

Ray


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## middle.road (Jan 13, 2018)

Looks like Groz is in India. Their offerings pretty much match the old Armstrong catalog page that I have that I use for reference. 
http://www.groz-tools.com/index.cfm?md=Content&sd=Product&ProductID=107


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## cascao (Jan 15, 2018)

See my bump straight knurl tool!


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## cascao (Jan 15, 2018)

T. J. said:


> Nice work!  I like the 2-piece arm design, which simplifies the build process greatly.
> 
> I am in the process of building one with 1-piece arms, which requires milling the slots.  So far, I have broken 3 end mills.   The learning curve on a milling machine is steeper than I anticipated...



Designed my bump straight knurl tool with your comment in mind.


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## cascao (Jan 15, 2018)

Someone have a rule or a chart relating knurl pitch to part diameter?


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## ddickey (Jan 15, 2018)

https://littlemachineshop.com/reference/knurler.php


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## cascao (Jan 16, 2018)

ddickey said:


> https://littlemachineshop.com/reference/knurler.php



What I want is a rule or a chart to scale the size of the knurl and the diameter. In order to knurls not apper too rough or too

....intersting Reed Machinery knurls data


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## ddickey (Jan 16, 2018)

I think this one was posted here too a while back.


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## cascao (Jan 22, 2018)

Now fixed my QCTP 110 knurl holder.


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## jayman (Feb 6, 2018)

cascao said:


> What I want is a rule or a chart to scale the size of the knurl and the diameter. In order to knurls not apper too rough or too
> 
> ....intersting Reed Machinery knurls data


Suggest you buy diametral pitch knurls (accu-trak.com is one source). For example, 96DP knurls will track properly on a work blank diameter that is any multiple of 1/96 inch.


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## middle.road (Feb 6, 2018)

jayman said:


> Suggest you buy diametral pitch knurls (accu-trak.com is one source). For example, 96DP knurls will track properly on a work blank diameter that is any multiple of 1/96 inch.


Yeah, yepyep, the Armstrong (NOS) wheels that I picked up are odd, their pitches are 14, 21, 33.
Other are all over the place. B&S had 12, 14, 16, 20, 25, 30. And then there is also 45, 50, &80 that I've come across.
Seems the more I learn about knurling the more confused I become.


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## pstemari (Feb 24, 2018)

cascao said:


> Someone have a rule or a chart relating knurl pitch to part diameter?


The rule is that the circumference of the part has to be an exact multiple of the knurl spacing. Eg, if your knurl has sixteen knurls per inch, then the circumference has to be an exact multiple of a 1/16".

This results in weird diameters because π isn't 3, despite the Indiana State Legislature's attempt to declare otherwise.

The solution is to get a DP knurl. DP knurls already have the factor of π built in. For example, a 64 DP knurl works with any part that's an exact number of 64th's *in diameter*, no dorking with π required. 80 DP knurls work on anything an exact multiple of 1/16" *or* 0.05" in diameter, which is super convenient. 

Sent from my Pixel XL using Tapatalk


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## blu73 (Nov 28, 2019)

Okay, even though this thread was started over a year ago, I would like to let you know of an American manufacturer of knurling dies.  Take a look at what these folks have to offer.



			Knurl, Knurls, Knurling Tool Holders, Thread Rolls, Spline Rolling Heads and Dies, Made in United States of America!
		


Sorry, I don't know how to make a "hot link" to get you to the site.

Russ

Well, it looks like when I hit the button to post the reply, the link sort of reformatted itself to become hot.  Cute.


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## ddickey (Nov 28, 2019)

I think there might be some affiliation there between Form-Rol and Accu-Trak. They are on the same street only a mile apart.


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