Can you knurl juma?

[Chili Palmer]

This is a non-pool related project but I would like to knurl some juma to make a knob or two for a project I'm working on. The link below shows what I want to make. My original design had silver accents so I was going to use aluminum (or similar) but have since decided to add some ebony and a black knob would be perfect. Yes, I could buy one for $12 but what fun is that, besides, this is a special project for a really good friend of mine and I want everything to be handmade. And I don't have a knurling tool yet, just ordered a cheap amazon one but it won't be here for a while.

Any input would be appreciated.

Abalone Top Dome Knob - StewMac

Tele knob shape with handsome abalone inlay.

www.stewmac.com

P.S. I have read about knurling delrin and it seems to work just fine but I happen to have a piece of black juma on hand.

 

[Kim Bye]

Juma is kinda brittle. i couldn't get nice deep knurls when I tried, maybe i have a crap knurling tool, but i just couldn't get a staisfying diamond pattern.

 

[Ssonerai]

Hardinge cut knurl tool? Will do about any diamond angle.
An alternative to diamond knurl for knobs is to use a single point 60 deg tool and index the work. (Like coin edge). Then step off and turn circles. The cut knurl comes out looking plaid/square blocks and most can’t figure out how it was done.

 

[DaveK]

A rose engine would do the trick I think. They are very expensive and look a bit tricky to operate but the work they turn out is fabulous.

http://www.the-sot.com/ to see a little about ornamental turning ... knurling is about as crude a pattern as these folks would consider.

CNC cut knurling would be another route, or perhaps helical/spiral milling : https://johnfsworkshop.org/home/pro...elical-milling-links/helical-milling-13-9-10/

These suggestions assume that conventional knurling that "forges" the material is not possible in juma, and a cut pattern is the only way to get reasonable results.

Good thing this is not about cues because I am not a cue maker.

Dave

 

[Chili Palmer]

Thanks all for the responses.

DaveK, it's funny you mentioned CNC, I just picked up a little cnc machine and last night I realized I could just use that.

On top of that, I'm going to do it in Ebony to match the other ebony in the project.

I'm going to try to start working on it tonight but it might take a bit, I've had my machine for a about week now Going to start with some pine/fir then move to a cheap hardwood to get the process down then move to the ebony. I'll post up my results.

 

[Chili Palmer]

And wow, I looked through the SOT website, damn, that machine is pretty cool. It's like an ancient CNC lathe.

 

[DaveK]

And wow, I looked through the SOT website, damn, that machine is pretty cool. It's like an ancient CNC lathe.

There is an American company making rose engines : https://lindowmachineworks.com/

I've often thought that an ornamental turned pool cue handle would be cool.

Dave

 

[Chili Palmer]

There is an American company making rose engines : https://lindowmachineworks.com/

I've often thought that an ornamental turned pool cue handle would be cool.

Dave

20K for a full setup - ouch. Looks like you can get in for about 4-5K though, still a bit much if you're only doing it as a hobby. (Please don't ask how much I have in tools in my garage for my hobbies )

I think the old chinese cheap cues turned me off to any sort of ornamental stick. I instantly think of 4 or 5 piece cues in a little box that are about as crooked as dog's hind leg. I imagine if done properly it would ok.

 

[Ssonerai]

Thanks all for the responses.

DaveK, it's funny you mentioned CNC, I just picked up a little cnc machine and last night I realized I could just use that.

On top of that, I'm going to do it in Ebony to match the other ebony in the project.

I'm going to try to start working on it tonight but it might take a bit, I've had my machine for a about week now Going to start with some pine/fir then move to a cheap hardwood to get the process down then move to the ebony. I'll post up my results.

Chit, with that you could do stuff like miniature overlapping fish scales (modified “engine turning”) nice & quick.

go ahead & prove the program on softwoods but be advised ebony will be much easier so long as the tools are sharp. Closer to matching plastic compared to pine or even oak which will tend to chew up.

smt

 

[Chili Palmer]

Chit, with that you could do stuff like miniature overlapping fish scales (modified “engine turning”) nice & quick.

go ahead & prove the program on softwoods but be advised ebony will be much easier so long as the tools are sharp. Closer to matching plastic compared to pine or even oak which will tend to chew up.

smt

Yep, I did some test pieces on 1 x 4's and they looked like shit, threw in purple heart and it was perfect, same program. Definitely a difference.

 

[CuesRus1973]

Juma is kinda brittle. i couldn't get nice deep knurls when I tried, maybe i have a crap knurling tool, but i just couldn't get a staisfying diamond pattern.

Juma? Brittle? Hardly. You have it confused with something else. I believe it might not knurl but brittle? No chance. I put a rod in my lathe chuck and hit it with a hammer. I've dropped rods on end on concrete. Nothing.