Knurler build

[Naiveambition]

Have been working on a 1/2 scale tripod for my latest project. Some parts require a knurled edge and I haven't bought one so I decided to try and build one.
I used 5/8 inch square steel bar. Pins are steel that I think will need to be hardened. For the center bolt I used a oversized machined bolt, turned and threaded to 5/16. Swivels I believe to be stainless.

If it turns out correct I should be able to knurl from 0 up to 2 1/4 inches still have a few operations that I will document. Here is where I'm at so far

 

[Naiveambition]

Today's work required a 28 degree slot milled for tightening bolt clearanceView attachment ImageUploadedByModel Engines1452213370.244905.jpg
So I broke out the rotary table and made quick work of it. View attachment ImageUploadedByModel Engines1452213609.842458.jpg

Here is the tightening setup. I used the longest bolt I had, and was still a little short, so I will need to make another. I I have read numerous threads on installs so I'm relatively confident I can pull it off, especially with the help here.anted to prove that it works before more work is needed.

View attachment ImageUploadedByModel Engines1452213843.178999.jpg.
The top radius was turned using a 1/2 ball endmill. Center slot accepts 5/16 bolt. Pins are .250. I have another knurled for push knurling, and noticed it gouged the bolt from the turning pressure, so will need hardening.

All that's left is to sand off the coating it comes with, which is tough as nails, and paint for some rust protection.

 

[10K Pete]

I've purchased two knurling tools of that type and made one, and have one
more to build to get it right. I've re-worked one of the purchased units by
extending the tightening knob about 3" so I don't bang my knuckles on the
darn chuck, and replaced the pins with hardened dowel pins. Anything less
doesn't hold up. But that unit still didn't work as the arms wandered all over
the place ruining the knurl. So, I shimmed the arms to the body so there was
about zero clearance and reamed and re-pinned the arm pivots. That worked
for a few jobs but the steel was just too soft and it loosened up again at the
joints.

So I made a quickie proto-type of my design and it works fine. So now I
need to make it properly out of heat treatable steel with proper tolerances. It's based on one I saw in Model Engineer magazine some time
ago and has long arms trapped by two side plates. Really takes the slop
out of the unit.

I guess what I'm saying is I hope you have success but be prepared to go
further.

Pete

 

[Naiveambition]

Here is a in action photo. Worked good and no pressure on my lathe bearings.View attachment ImageUploadedByModel Engines1452223541.487285.jpg

The project I'm working on. It is the traversing, elevation screws for a 1/2 scale ma deuce or m2 machine gun.
The plans were from ccs prints, and is built using a donor .22 rifle. I'm almost thru the tripod used with it.View attachment ImageUploadedByModel Engines1452223793.120392.jpg

I used two different knurling tools. The small hand wheel was used just pushing the knurl into the wheel. And the large one was used with the knurling tool I made. Happy with the outcome and now need to buy the remaining knurl sets so I can do diamond patterns. So at 65$ for a bought one I have built this one for roughly 10$ so that's good in my book.

 

[Blogwitch]

After trying a few of these scissor type tools, I have yet to find a good one that gives nice coarse and sharp knurls, but because I have a fairly large machine with good head bearings I can use side plunge cutting instead.

Normally, you use straight knurl wheels in singles in a plunge fixture as sometimes you can get some bad results by using them in pairs, as shown on the large wheel you have made, they should be more spaced apart and much deeper, caused by the wheels not being in sync with each other.

BTW, straight knurling for tightening/undoing, diamond knurls for gripping, as in tooling handles, centre pops, scribers etc..

John

 

[Naiveambition]

When I bought the wheels, if I remember correctly these were the medium or fine size. Even on the wheels themselves the knurl is not very deep. Maybe I got lucky this time, since this is pretty much the first time knurling , that all the lines are spaced evenly. My preference would be a little deeper but it grips good now so I am happy.

I found it really hard to get enough pressure to plunge the work. Are you supposed to anneal brass beforehand? The holders pattern was much deeper.
And also watching knurl videos I noticed that diamond patterns are put on using scissor type holders while engaging the lead-screw. So how does it line up then? If they were mirror opposites, maybe they would follow the pattern of each other. Could this be possible with the straight knurls also?

 

[10K Pete]

Traversing the part while knurling requires a very tight tool. That's the
problem I was having. The arms would wander, not stay straight, and then
the knurls would be out of line and go crooked. The big scissor unit I have
has two arms that cross. I took all the play out and it tracks pretty well.
But it's way too big for the model size stuff.

Try traversing a bit of scrap with yours; let's see if it's good.

I've never had to anneal brass. 12L14 knurls really well!

Pete

Edit: I should also mention that the wheels have to have a chamfer on the edges
for traversing.

 

[Blogwitch]

Actually for double wheel pressure knurling, and also single wheel as well, the workpiece should be cut to an exact size so that the knurls form a perfect matching pattern around the circumference.
There are formula for working out what size the piece part should be based on the diameter of your knurling wheels, but 99.99% of the people just put on the cut, slap on a load of cutting lubricant and hope for the best, as I do.
As I said before, I have strong enough head bearings to take side pressure knurling, and I do occasionally power feed long pieces with tailstock support, but because of what I said about calculating out the perfect diameter of the piece part, the results are sometimes not very good., but useable.
If you are after perfect knurls, you would need to invest in dedicated knurling toolholders that actually cut the knurl rather than the pressure ones that rely on a combination of cutting and deformation of the surface, but unless you can make your own, they work out rather expensive.

John

 

[10K Pete]

Some where on one of these forums there was a thread about cut knurling and
how to make a tool for it. While there are fancy tools, one of the guys showed
a pretty simple on he'd made that really worked well. For the life of me I can't
dredge up that thread!!!

Most of the stuff I do is little like the knob on a needle valve so all I need most
of the time is a small scissor type.

Pete

 

[deverett]

Some where on one of these forums there was a thread about cut knurling and how to make a tool for it. While there are fancy tools, one of the guys showed a pretty simple on he'd made that really worked well. For the life of me I can't dredge up that thread!!!
Pete

Here's one design for starters. Gadgetbuilder usually has very good designs.
http://www.gadgetbuilder.com/Cut_Knurler.html

Dave
The Emerald Isle

 

[10K Pete]

That's the one!!! Thanks for finding that. I'm very interested in that concept
and want to try making one as soon as I finish the mill re-build. Now I can!

Pete