Here isa question from a Newbie about Knurling

[Doc Hoy]

Folks,

I am not a machinist, I am a hobbyist. I have never attended any classes, worked in a shop. Everything I know is what I have read or have been able to pick up as I make scrap and ruin stock.

I have a small lathe (Actually the grizzly 4015 3 in 1) and I was doing some knurling this morning. First time I have messed with the knurling tool. I was using a tool supplied with the Quick Change tool post T10166. (Great tool post, by the way IMHO)

I have seen photos of these used with the height adjusted so that both wheels contact the workpiece simultaneously. You are applying the diagonal-down and the diagonal-up at the same time. I found it very hard to use the tool this way. I simply could not get the height adjusted such that both wheels applied the same pressure. I kept winding up with one or the other cutting deeper.

I finally gave up and adjusted the height so that only one wheel was on the center with the workpiece at a time. So I cut the diagonal down first and then the diagonal up.

I found that I need less pressure and the problem of misadjustment went away. I wound up with a nice job. (A dial locking screw for my milling machine)

How do you all use the knurling tools? Both wheels in contact at the same time or only one at a time as I realized seems to work better for me.

Tnx,

[websterz]

The best advice you will get from me will be to not use a bump knurler on a small lathe. A small machine is not rigid enough and you could really tweak things in a bad way. A scissor type knurling tool is the way to go.

[jim rozen]

Knurling is really the toughest job
for a small lathe like that.
Second only to cuting off. There
is a huge amount of force in play
at the cross slide, and there are
huge lateral forces at work trying
to push the part into the collet
or chuck. As mentioned a scissors
type knurling tool absorbs most of
the force and is a best choice for
small machines.

Many of the older bump knurling
tools were self-centering, either
the old armstrong kind with the
floating pair of wheels that were
on a pivoting insert in the tool,
and the three-way kind (fine,
medium, coarse) where the wheel
that holds the kurling wheels is
free to spin all the time.

Jim

[Doc Hoy]

To both Jim and Web,

When I was using the darned thing I found myself wondering what was happening to the bearings in the head stock.

Also got similar advice offline regardng the self centering tendency of the tool post. I did not try that but I liked using only one roller at a time to reduce the force required.

Tnx,

[CarlD]

Doc, with the lathe not running put the knurler tool on the tool post but don't lock it. Carefully feed the knurler into the work and with your hand move it up and down on the shaft and as you get the knurler totally against the shaft it will center it's self. Now lock the handle and start knurling.

With a small lathe I suggest you get the scissor type mentioned earlier, it's easier on your lathe and easy to center.

[Doc Hoy]

You have made a believer of me and I will do as you say. But let me take this just a bit further in an effort to make me even more familiar with the tools I am using.

I have a milling machine like the Grizzly 3358 two horse job. Bought it used and many of the markings are gone so it may be a Grizzly. If not, it is identical.

My thought it that this machine is capable of withstanding more side force than the lathe. It would be relatively easy to set up the knurling tool to work on the milling machine. Then after carefully centering as you recommend, use the milling machine for knurling. I do accept that the most logical thing to do is follow your instructions about scissors type knurling tools. But I enjoy learning about the processes involved.

Does my idea make sense? (Maybe everyone else in the Western Hemishere is already doing it this way.)
Am I right about milling machines and side force including this machine which is much heavier than the 3 in 1 I am using as a lathe?

[Frank Ford]

Take a look at Bill's recent thread, here:

http://www.chaski.org/homemachinist/vie ... hp?t=83580

[GeneT]

First, you'll probably want a scissor type knurler to keep the stress off your bearings. Then you'll want to make sure you're using quality knurls (the wheels) - I've never seen a quality import knurl.

Finally, wait for Harold to chime in. I learned knurling from one of his posts probably 7-8 years ago and haven't made a bad knurl since.

GsT

[Doc Hoy]

Fellas,

Still with you. I tried floating the knurling tool in with the lathe stopped as suggested by Carl D and it worked like a champ. But then after reading all the posts about side forces, I did not have the courage to do anything with it. I am at work now with the lathe still sitting there as I left it this morning. Part in chuck, tool on tool post. Cross slide moved in to contact the workpiece. I simply did not have the courage to turn the SOB on. I could just imagine hearing the lathe complaining about the forces.

So next step is a scissors type knurling wheel holder. I might actually try to make one. It does not look that complicated.

I can see how it completely eliminates side force. But when I move forward I will keep knurling with a mill in my mind. (The other thread is real informative until they started talking about building code requirements in California.)

[CarlD]

Doc, I wouldn't use a side force knurler on the mill but you could use the scissor type on the mill I guess.

[Harold_V]

Doc, I wouldn't use a side force knurler on the mill but you could use the scissor type on the mill I guess.

That's more or less my thoughts, too.

There are a couple issues that could be troublesome, relying on a mill for knurling. One of them is the limited ability to grip the object to be knurled.

Unlike a lathe, where you have options in holding pieces that are machined, you don't normally have at your disposal various chucks. Gripping anything in a typical drill chuck isn't the solution----it damages surfaces and has a limited range.

Collets for mills typically come in restricted sizes, so they wouldn't be a solution for many instances, and, lastly, you would be drastically limited to the length of the object.

In a lathe, you have the tailstock for support. It would be far less convenient on a mill to support long objects, and you'd be limited by the distance from the spindle to the table. Support wouldn't be an issue if a scissor type knurl was applied, however.

All in all, knurling is best performed in a lathe, but one does what one must when in a corner. I have used a mill for knurling, but only because I knurled a flat surface.

Harold

[GeneT]

I have used a mill for knurling, but only because I knurled a flat surface.

Harold

Now *that* I would like to see!

GsT