Knurling Question

[mzayd3]

That is good idea. I will look for one. I am interested more in straight knurling. How does scissors type work for straight knurls? I understand scissors will not have a problem if it is diamond style but I dont understand how it will work for straight.
n
Thanks
Prasad

I imagine that to use straight knurl wheels in a scissor type knurler that you would replace one of the wheels with a bearing. Otherwise, both wheels would cut resulting in a non-sychronized knurl.

 

[prasad]

I imagine that to use straight knurl wheels in a scissor type knurler that you would replace one of the wheels with a bearing. Otherwise, both wheels would cut resulting in a non-sychronized knurl.

Thanks. But would't the ball bearing exert pressure and flatten the tips of the serrations produced by the single straight knurl mounted on the other side of the scissors?

 

[prasad]

Good HSS knurling wheels are the trick. I found the wheels on the cheap imports to be soft and not very sharp.

Good point Martin, the knurl I have is an import and could be of poor quality. I have search for a bunch of knurls I had picked up at Cabin Fever Expo earlier in April this year. I know some of them were US made but previously used.

Thanks
Prasad

 

[wawoodman]

The pattern is a function of the knurl type you use, not the knurling tool itself. Straight knurls are generally matching, while diamond knurls have a right hand and left hand pattern so they cross each other as the pattern is made. A scissors knurler can use either type.

If you do make a scissors knurler, consider mounting it to the rear of your cross slide bed. This greatly improves rigidity and gets the tool out of your line of sight.

Mikey,
How would you mount to the rear of the bed? I'm interested!

 

[prasad]

And there are any number of plans for a scissors knurler on line. A pretty good starter project. I even made one myself!

Mike
I googled and found plans for scissors knurlers. Isn't it necessary that the knurl holder, etc., must be hardened? I am not sure I would be able to do it. I am not sure if they can be used without hardening as they may buckle under pressure. The straight knurler I bought from Grizzly is hardened.
Prasad

 

[prasad]

Mikey,
How would you mount to the rear of the bed? I'm interested!

I think he means the tool would be on the other (rear) side of the object to be knurled from the back side and the two rollers would face the operator. The lathe operator would then be able to view the rollers.
-Prasad

 

[wawoodman]

Mike
I googled and found plans for scissors knurlers. Isn't it necessary that the knurl holder, etc., must be hardened? I am not sure I would be able to do it. I am not sure if they can be used without hardening as they may buckle under pressure. The straight knurler I bought from Grizzly is hardened.
Prasad

I didn't harden mine. I don't know how to do that.

Right now, I'm working on the Tom's Techniques knurler. It calls for hardening some of the parts, so I hope it's covered in one of the videos!

 

[wawoodman]

I think he means the tool would be on the other (rear) side of the object to be knurled from the back side and the two rollers would face the operator. The lathe operator would then be able to view the rollers.
-Prasad

But how would you do that? I don't think my cross slide goes that far. Do you have to make a different mounting method?

 

[prasad]

But how would you do that? I don't think my cross slide goes that far. Do you have to make a different mounting method?

On my G4000 lathe with cross slide mounted on the second hole and moved all the way to the back I think, it can be done. I dont have a scissors style knurler yet though. Let us wait till we hear the real answer from Mikey

 

[mikey]

Good morning, guys - you've been busy!

First, straight knurls used in a scissors knurler are a matched pair - both wheels will track in the same pattern. The coarser the straight knurls are (fewer teeth per wheel), the less the potential for mistracking.

Rear mounting a knurler requires a cross slide with T-slots, which the G4000 has. If you don't have T-slots you cannot do it without major surgery. If you do, however, it is the most solid way to mount the tool. Knurling produces pretty high forces, most of which are taken by the tool instead of your spindle bearings. That force has to go somewhere and it is passed on to the mount. In the case of a rear mounted tool this force pushes down on the cross slide where it is handled by the gib that is designed to handle that force. This translates into a cleaner knurl. The other major advantage is that rear mounting the tool clears your line of sight and gives you more room to work.

There are plans for making a knurler on the net - choose one you like. The only parts on mine that are hardened are the axles and you can use drill blanks for that; the rest can be mild steel. The most important thing re the tool itself is that there be no lateral play in the arms; on mine, there are plates to limit this and it was machined with zero play. The plates were then filed so the arms just moved freely ... but no more.

I'm having trouble posting pics. I'll get them posted when I figure it out.

Good knurls are important, as is a radius on the knurls if you are going to do any axial running (making a knurl longer than the knurl is wide). I like FormRol knurls. AccuTrak makes convex knurls made for axial running, as well.

More later - gotta' run.