Straight knurling ???

[turmite]

Hey guys,

I'm a wood worker and have little to no metal working knowledge. I need your help. I manufacture rifle stocks and pistol grips and regularly use brass, alum and stainless knurled insterts in the process.

I have a part that I want to design and I need some questions answered.

Is stock material accurate enough to use for the od. I.E. 1/2" round in any on the materials mentioned.

If the material were to be .400" long with a tapped thru hole and then a counterbore, what would the od measure after straight knurling, or, is this something that can be controlled?

Would the hole for the insert be made for the minor diam of the material or something between that and the od?

Mike

[Geof]

Brass round bar will normally be within +/- 0.002" or better, of nominal diameter.

Stainless steel can vary; you can get ground finish which will be within 0.0005" but rolled finish may vary by 0.001".

Aluminum extruded bar can vary widely; depending on the nominal size it can be +/- up to 0.01".

Probably all of them are precise enough for your requirements.

It is difficult to predict the OD after knurling as it depends on how coarse the knurl is; 0.02" to 0.05" on the diameter is probably the range.

Your hole size is going to depend on the material you are pushing them into and even small than the root dia. of the knurl may be best. I think you would need to experiment.

Final comment: Why make your own, you can get knurled inserts of all types that are used in molded plastic products.

[turmite]

Geof,

Thank you for your response. Last first, is that one of these items has an odd thread, specific diam and depth of counterbore for the head. The others I might be able to find what I need, but then you get into the thing of how many thousand of these do you want per month! I'm a small business with small needs!

Mike

[bwpigeon]

What are your specific requirements? What kind of numbers are you needing? Do you have a print of each of the items?

I have a full time job but have several machines that are capable of making what you need. This is my first love as work goes. I live out in the country in a small town so making a living in the machining business is out of the question. So I take on small jobs more as a hobby than anything. It takes the stress out of having to sit at a desk all day long. It's just a good job that pays the bills and allows me to do small short run jobs in the evening and weekends. So call it my therapy. So if you are interested drop me a note. bwpigeon@restel.net
Bruce

[Delw]

I run straight knurls all the time they are a tad different and more picky then a cut diamond knurl,
a few things I personally have learned.
Never run stock alum bar and expect a good knurl, you will have runout problems and your knurl will look like crap,
I always take a skim cut to true up the alum stock.
like said previously depending on the knurl pitch will depend on the depth of cut. if you need a certain od dia and tol, state it in your print AFTER knurl, there is no problem holding a .001 dim. on a straight knurled surface providing the dia is cut true before the knurl.

also because the straight knurl relies on pressure the length of you part is going to vary on the od tol. if the part is too long you can program a slight taper in the od tool and the knurl tool to keep your tol.

Delw

[turmite]

Hi guys,

This thread was posted two years ago! I can't even remember what it was for now.

Mike