Material Request...

[BKengineer]

I am redesiging a tool for an automotive shop.. A bearing press device. The one end is threaded where a bolt treads thru and drives the bearing out.. The bracket threads have been stripped. The mechanic said it is hardened steel to 12.5, metric (???) . Any ideas for material I could use that would not strip out? or Should I just redrill and tap the existing piece with a different thread and fab. a bolt to match..

Thanks

 

[dbooker630]

If your mechanic is referring to a fastener spec, 12.5 does not make sense. The 12 part would equate to about 38 HRC but the 5 means that min yield is only 50% of min tensile stress, or not hard.

Fasteners in the metric designation would normally be marked as 12.9. This class is very sensitive to embrittlement; if you were actually using a 12.9 in this application maybe the threads were already cracked.

 

[NickE]

Go to a bigger bolt size if you can, with a coarser thread if possible.

I would, depending on size of the tool, go with either O1 or 4140/4340.

nick