Knurling tool

I bought this a while ago but never got around to using it until this week as I wanted to knurl a couple of aluminium knobs, however disappointed with the results.

The knurling wheels look different to what I have see being used on YouTube. ie the ones used are a left and right straight pattern and when combines make a diamond shaped knurl but the ones on my tool are different.

To be honest it was only £20 so I suspect that’s why it’s not very good?

Edited By petro1head on 24/03/2023 11:49:45

Not necessarily the tool I'm afraid, more likely your technique. It is difficult to get right ( how do I know that) but lots of practice and the correct application will get you there. Plenty of discussions on here about good methods if you do a search.

Regards Mike

I would expect the type of tool you have to be equipped with single angled wheels as per your first image. The diamond pattern that you show in the second image would normally be for use in a single wheel push in knurling tool. Would suggest getting a new pair of wheels.

John

So you think there is nothing wrong with the tool just replace the wheels then

I have one very similar, it works for me with the single pattern wheels.

Did the knurls on these with them.

John

Cheers, have ordered some replacement wheels

As Apprentices, we were told to adjustb the knurls for a cut of 0.010" (Never quite worked out how to measure that. Set up knurling wheels to just touch the work when 0.010 before centreline, withdraw and tighten slightly might be the way to do it?

Have always adjusted the setting by eye, so that it looks right and then worked to that. Rough and ready but does the job.

That, when ntraversed along the work, with diagonal wheels has always produced acceptable results

As always, practice makes perfect.

Howard

Just to chuck my pennyworth in it doesn't look as if you have gone deep enough, as your wheels look fairly coarse.

I would remove those wheels, measure the diameter, width and bore and buy some standard types, then your knurling will look much better.

I have a similar SOBA tool from RGD, it came with the angled slotted knurls as your first pix. When I ordered it I also ordered a set of fine wheels from RDG, both work fine on steel, ali and brass. Put a bit of 3in1 oil on the wheels to keep them running smoothly...

It looks like you haven't quite got the wheels square to the job by the witness marks on the wheels.

I have what looks like the same tool, with the same wheels, and it works OK.

How are you using it?

I set the wheels just protruding off the end of the rod, positioned hard finger tight just off the centre axis. On starting the lathe the wheels are wound harder into the job by the top-slide to get a deeper cut. And the lathe is set to power the saddle towards the headstock, so the tool runs along the rod knurling as it goes.

Petro1head's photo suggests to me that the tool was pushed straight on and left to turn, and it rolled over the knurl repeatedly and mangled it. If so, I never do that - the knurling tool is always driven sideways as well. With plenty of cutting fluid.

Dave

PS - I'm self-taught and could be doing it wrong!

Edited By SillyOldDuffer on 25/03/2023 11:24:05

What has worked for me is this: Increase the pressure on the knurls until they track properly. I admit I have never used the diamond pattern rolls. I have a left and a right knurl in my knurling tool. I am not sure how the diamond pattern rolls work when traversing the work. I know the right/left combination work well when traversing the work.

I thi k i have cracked it

I never tried to knurl something yet but I recognized that pattern from Machining Fundamentals book. It is called double-cut knurl. It has something to do with the alignment of the wheel bellow or above the center.

Edited By Sonic Escape on 31/03/2023 11:44:34

Edited By Sonic Escape on 31/03/2023 11:45:24

Nearly but not quite there yet, showing a double cut, look at bottom illustration in Sonics post above.

You have - I'd be happy with that. Although not perfect diamonds, which the tool will do (practice!), it has the important merit of not being too sharp. Knurls exist to improve grip without abrading flesh, and many smart good-looking knurls are actually failures! Even though their owners are delighted with the appearance!

Dave

This is what knurling should look like. Click on the image to get a closer view.

Contrary to Sonic's text book I always start with the knurls off the work. That is after first touching the knurls on the diameter at 12 and 6 o'clock and applying a cut to the knurls with the adjuster incorporated in the knurling tool. The work should always have a chamfer to lead the knurls into the work.

The faults in the above OP's knurling are more than likely due to sideways play in the knurling tool arms. There needs to be no lateral movement at all. The pivots should be a true diameter and not the crests of a threaded bolt like so many that I have seen. Poor fitting pivots contribute to the lateral movement.

By starting on the work as shown by the OP, each wheel will adopt its preferred position. Which will be anything other than in line with one another. As I said recently on the same subject the knurls are no different to helical gears with the same forces acting upon them. This is why in the above shot by Petro1Head one knurl is predominate.

Regards

Gray,

Edited By Graham Meek on 31/03/2023 15:29:42

I tried to make the tool as sturdy as poss but its a fairly cheap one.

With a cross pattern built into the roll it should work as a single wheel bump tool.

I am all for keeping costs down, that is why whenever possible I make my own tooling. That way I know the tool is done to an acceptable standard to me.

The tool shown could be improved especially if the bolts used for the pivots are just plain set screws/bolts, that is threaded up to in under the head.

Reaming out the holes to the next size up and fitting Shoulder screws would be a good move. Shoulder screws can be made or purchased. As would fitting shims either side of the arms to make the joint a closer fit.

Generally,

Lastly there is a trend to fit large wheels in the knurling tools these days. The old school sizes used to be 0.5, 0.625 and 0.75 "or 13. 16 and 19 mm approx. These wheels have less area in contact with the workpiece, they need less force to get them to cut, or more correctly deform the workpiece.

One only has to look at the rear wheel of a tractor, where the size is such, so as to lessen the impact on the soil.

Regards

Gray,