how to make knurls,with pictures

YEARS ago,there was a discussion on how to make knurls by running the blank knurl against a rotating tap. Old Biker had also done this. Guys begged for pictures. at the time I was just learning computers(still am).

Well,FINALLY,here is an illustrated story on making knurls. The lathe is my Hardinge HLVH. It is a 1964,and I slowly rebuilt it. The carriage's top had many tiny marks from use over the years. This carriage top just doesn't unscrew like most. It is a big L shaped casting that is also the front of the carriage. My grinder could not accomodate it. I didn't want to take it all apart,so I scraped and flaked the surfaces. It was the easy,and sightly way to get rid of the little marks.

Pictures will follow.

Very cool, thanks for posting.

Very Cool....... I have seen the method of using a tap as a hob in old books and have only used it once in brass......... what steel are you using and do you temper them after hardening?

Thanks for posting this.

Blast it,I just spent a lot of time describing the processes,and it all vanished.

Pic.#1shows turning a piece of 01 drill rod,3/4" to the same contour as the tap. If you don't get the contour reasonably close,the tap may chew up the blank.

#2 shows a ROUND shank knurl holder I made. It can be clamped in the tool post,and tilted at angles up to about 20º down to the right to increase the angle of the rope being generated. You cannot tilt BACKWARDS to the left much,or the tap will chew up the knurl. You CAN tilt back a few degrees,to make your knurl threads VERTICAL. Presenting the holder dead horizontal will make the knurl with the same thread angle as the tap.

#3 shows cutting the knurl. MAKE SURE the knurl rotated freely,or you will get ruined by a flat spot. Make sure the knurl fits pretty well into the holder,or the coarse sand type chips can get between the knurl blank and the holder,and jam your knurl,ruining it.

#4 is a fuzzy picture of some knurls I made. Not all were made by this method,but you can make out the extent of "rope tilt" you can make by tilting the holder.

#5 shows my little Royal roller bearing center,with CNC type nose. I like this nose because I could make snug sleeves with female centers to support the outboard end of the tap. With smaller taps,you must support them,or snap them off.

Use oil on the knurl's axle,and cutting oil on the tap. Run the lathe slowly.

Try to use taps with MULTIPLE FLUTES. 2 flute taps don't engage the knurl at all times,and probably will ruin the knurl. The knurl must be engaged at all times,and turn freely. It is a bit delicate to do.

Feed the tap in SLOWLY. All kinds of things can go wrong if you rush. Give the tap time to cut.

I harden these knurls and draw them to a purple color.

I generally coat them with PBC No-Scale from Brownell's gunsmithing so as to keep them bright,and not burn the tips of the teeth while hardening them.

These knurls will be the sharpest ones you will ever feel if a good,sharp tap is used(and only sharp taps should be used!).

IMPORTANT: When using these concave knurls,YOU MUST carefully make your surface to be knurled the SAME contour as the knurl. If you fail,the steel you are knurling may work harden,and ruin your knurl.The brass you are knurling will start to flake everywhere,and become a mess.

Convex?

Argghhh. Between the time I read your original post and the time I posted this inquiry you filled many of the blanks.

Mr Wilson,

It is evident from the pictures how the concave knurls were made. How about a few words on the convex ones? You must have pivoted the tool holding the blank?

Your post inspires me to make a few mnurls that I have been thinking about....

I assume you are using O-1 tempered to a light straw???

TIA,
Denis

Convex knurls are made by carefully contouring the knurl blank to fit the other knurl,and knurling off the concave one. They really serve as "mother knurls" should you want to facilitate making more knurls.

Re read my LONG post to get all your needed small,important details.

gwilson said:

Re read my LONG post to get all your needed small,important details.

Click to expand...

Yes, I had edited my post to indicate it was written while you were posting your explanation. So our posts "crossed." That's OK as long as we don't get our wires crossed. ;-)

Indeed, you did answer most of my questions BEFORE I posed my question. The info is most appreciated. Thanks.

Denis

I wonder why my info vanished??

DO ASK any other questions you might have. This process has to be done right,or there is disaster!!!

gwilson said:

I wonder why my info vanished??

Click to expand...

This has happened to e, and I have seen messages from several others mentioning it.

Here's what I think. The board's software automatically logs you out if you are "inactive" for a few minutes. "Inactive" means communicating ith the board, ie. opening posts, switching forims, any activity that interacts with the board.

Writing a post doesn't count as interacting with hte board until it's posted, so if you spend more than a few minutes typing, the board logs you out.

On my browser, Safari, this reveals itself when I finish typing the message and click on the "Poste Reply" button. Instead of posting, I see a screen that asks for my usernam and password. I have found that if i enter them, and do NOTHING else, I am logged back in and my previously-written message re-appears. I can then hit the "Post Reply" button and it will submit the message in the usual fashion.

But if in frustration I do anything else, like hit "Enter" or "Tab" or some other button, my message disappears.

I do not know if this is unique to Safari.

I did quickly skim the user Control Panel to see if there is a way to stay logged in, but nothing jumped out.

I haven't had this happen on other fora with the same layout and server as this one. Some of my explanatory post get long,to.

When you know it's going to be long write it in a notepad first, then copy/paste it.

One thing I have done to avoid this very frustrating occurence is compose my message in Word or other word processing software and then copy and paste it into the message here.

Denis

I'm not very computer savvy.

If you think about it, every so often just highlight your entire post by holding the left mouse button and then hit the right mouse button and select copy. If you post disappears just start another one and right click and hit paste.

I guess you should only have to copy it once, before hitting "Submit Post".

I have a Mac.

Like Kyle says! I too have lost a lot of typing beforemaking a habit of copying before trying to post or preview.

Yup, if you have a lot of info to post, hit ctrl A (select all) ctrl C (copy) ocasionally as you go. I call losing the works divine editing. God's way of making me condense my thoughts, lol.

thank you for the advice,guys!

At about what speed to do spin the tap when cuting the knurling tool?

And how much pressure would you say you use to feed the blank into the tap?