Carbide neck bushings

[butchlambert]

A small bore gauge from Starret, a dial bore gauge (Sunnen preferred) or if you are experienced quality telescoping gauges are practical to measure. You could also mic the OD and use a ball mic to check wall thickness to ensure concentricity, double the wall thickness and you can extrapolate the bore..... Or are you fellas using a CMM to get it right.


Personally I am thinking anything stamped on the OD could influence the bore if it was done after it the critical dimensions are finished less so if stamped on the end but still possible. So etching is a good thing but if the identification is done prior to honing....?As far as concentricity is concerned I guess I don't have the confidence in the design and machining of the die to believe that if it were to be .0005 out of concentricity that it would affect the final product. I have OCD but I am failing to see the reward here with the exception of lube free.

If this is the only benefit I if you have the coin it's all good. Thanks for replying everyone.

Mine were painted? on the OD for a lack of a better word. The print was light enough on some that I engraved them. Concentricity of the OD to ID is not an issue. Bushings should float.

 

[Concha]

Concentricity of the OD to ID is not an issue. Bushings should float.

Exactly Butch.

 

[LHSmith]

Personally I am thinking anything stamped on the OD could influence the bore if it was done after it the critical dimensions are finished less so if stamped on the end but still possible.

Actually, Redding advises their bushings be placed numbers DOWN so as not to influence concentricity ( the stamping are often crude enough to cause the die to "cock" off of perpendicular as the bushing hits the top of the bushing retainer on the up-stroke of the press ram).
When you start getting fluting on your brass necks or rusty bushings you might change your mind.

 

[Concha]

Do you have any pictures of the fluting? This phenomena I am not familiar with. I have never seen anything like that .

The raised numbering is a non issue since the manufacturer has directions to mediate the issue. I use a Norton fine hone and lap the proud metal flat and obviously I still insert them down. As for the rust I live on the Gulf coast and try to keep my precision tools away from conditions that would cause rusting. If carbide reduces fluting and rust by all means its a bargain. Carbide does not grab because of the finish RMS and grain structure. I get that, I am not looking to argue or fight really, It just seems like overkill is all I was saying. But if you have the coin once again, it is a bargain. Accuracy wise.....?

Machining carbide is done with expensive abrasives and specialized tools. That doubles or triples the cost. Somebody has found a production shop to make these or it would cost more than 45. I'll stick with the no lube required and be happy. I have seen some other manufacturers vary .0005 maybe more and that is another good reason, precision.

My apologies for pursuing this discussion on your thread OP.

 

[butchlambert]

I buy all my carbide bushings from Bud Mundy or Benchrite when I see them at a match.
I do this so I can verify the actual bushing size with my calipers. Have not found 1 that matches what is engraved. Carbide bushings are my only choice.

JD

JD, I'm still confused. You said your calipers measure differently than Deltronic pins. I believe that, but you trust your calipers? As I mentioned before, I engrave some of mine on the OD of the body. It is very critical that the top of your bushing is perfectly perpendicular to the bore.