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

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.

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