# Gerrit's cut Knurling tool



## gerritv (Sep 11, 2022)

After the marathon My Most Hated Tool thread that was loaded with advice and opnions on knurling, I was reminded that while I had a previously made cut knurling tool, it was less than stellar output from it.
My first one was a design by Guy Lautard. It relied on sharpening the leading edge of a reguslar knurl wheel. Setting hte angle was fiddly, it moved too easily and it was tedious getting the thing on centre (which it turns out is vital to success).
We Can Do That Better made a clone of the Zeus RF231 large (which he wouldn't acknowledge was the source of his design  I'm not sure he had read the Zeus/Quick instructions, e.g. he ran the knurl over twice, which is not desirable.

Having trolled the net in the past for home shop makeable designs, I settled on the Quick RF231-LD to pattern after.
The back plate is .25" O1 Starrett ground stock, because I have a bunch of it. The shank is cold rolled .375 thick by .5" wide, silver soldered to the back plate at a specific height. The wheel mount is 6061 AL. The wheel is mounted on that at a location such that a horizontal line across the wheel through the centre is at the same height as the top of the shank. This makes it easier to align the tool vertically.

I bought the wheels from Eurotech Tooling in Oakville. Wheels are CA$35, HSS bushings/washers are CA$58 or CA$108 for carbide ones. The wheel in the video is 21.5mm diameter, 5mm wide with an 8mm hole. The wheel fits like a glove on the bushing, glad I didn't try to make that myself.

So, for the results: Yes boys and girls, this style of knurling is truly cutting. After a few tries to get the hang of it, there is a photo of stringy chips from coining a piece of 8.5mm diameter 6061. So no doubt that this tool cuts. Larger diameters result in chips, lots of them. 2 hpotos show without and with air blast.
Feeds/speeds: for the 8.5mm one it was turning at 1500 rpm, feed rate of 0.15mm/rev. the 21mm one was 1000rpm and same feed rate. Plunge in to pitch depth (so for a 1mm pitch wheel you go in 0.5mm radius/1mm diameter). The result is fully formed with sharp top. No visible diameter increase occured. (I didn't measure it).

To get horizontal coining the height has to be correct. Once I tweaked that I scribed a line on RH of back plate so I can realign if needed. The shank is angled slightly from 90dg, to get back clearance.

References:
-Zeus RF-231/LD https://www.hommel-keller.de/wp-content/uploads/2021/09/GA_zeus_231_DE.pdf (you can see what We Can ... cloned his from on RH side of this doc)
-Accu-Trak description of use: https://accu-trak.com/knurl-holders/cut-type-knurling.html

Cut knurl, no air blast
Cut knurl, with air blast


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## gerritv (Sep 11, 2022)

I'm waiting on some parts before making a mount with 14.5mm wheel (so I can knurl closer to shoulder) and to make a mount for the straight wheel, to make diamond knurls. 
More to come, eventually.


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## gerritv (Sep 11, 2022)

Some more trials: Nylon and Delrin, with more curly swarf. Materials that you can't form knurl.
Also a way of embellishing coined knurls with grooves. I recently saw this in G H Thomas' The Model Engineers Workshop Manual, page 179. You cut grooves with 90dg angle at intervals (in this case 2mm) and deep enough to cut just below the bottom of the knurl. A brass brush cleans it up very well. 1mm spacing would have resulted in square knurls.


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## Susquatch (Sep 11, 2022)

I think that settles that discussion most definitively @gerritv. 

Very impressive work too! 

I can't wait to make one for myself!


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## PeterT (Sep 11, 2022)

Very Nice. That's the way to knurl.


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## gerritv (Oct 27, 2022)

Some more video, made for a presentation to TSME:


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## PeterT (Oct 27, 2022)

Nice. 
I'm starting to question how bad I really need/want diamond knurl which presumably requires 2 wheels (like @Mcgyver design). I could live with straight axial knurls like your example, or make radial grooves for a 90-deg checked effect like your post#3  picture example.

Could plans be available at some point? Is TSME a ?? Model Engineer organization maybe?


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## gerritv (Oct 27, 2022)

TSME is Toronto Society of Model Engineers. Meetings are Zoom until spring 2023, hence me rejoining again. I didn't like the drive to meetings when I was living in Toronto, even less likely to go since I am now in St Catharines. My dad started taking me to meetings in the mid-late 1960's, been a member on and off since then.


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