Drilling hole in chrome plated hardened 4140

[Wisconsinite]

My buddy has a mini ex that needs a new bucket pin. He ordered this material:

How would you go about drilling a ~1/2" hole through the diameter for a bolt? Center drill and send a coated bit?

 

[1oddtech]

Probably start with an end mill to get thru the hardened layer on both sides and then drill

 

[bgaidan]

Probably start with an end mill to get thru the hardened layer on both sides and then drill

I made a pin a month or two ago and this is what I did. I think mine was only case hardened, not fully hardened like the OP's material. A hole for a retaining bolt doesn't really need to be super precise, so worst case, a center cutting 1/2 endmill can probably plunge right through it if the drill doesn't like it. Carbide drill would work too, but probably waste of $ for a single hole.



Edit: OP - sounds like he's already ordered it, but if not, that's pretty price for a pin and really doesn't need to be fully hardened like that. He can get an actual pin that will likely just need to be cut to length and/or drill on ebay for about 1/4 of that price.

 

[Wisconsinite]

I made a pin a month or two ago and this is what I did. I think mine was only case hardened, not fully hardened like the OP's material. A hole for a retaining bolt doesn't really need to be super precise, so worst case, a center cutting 1/2 endmill can probably plunge right through it if the drill doesn't like it. Carbide drill would work too, but probably waste of $ for a single hole.



Edit: OP - sounds like he's already ordered it, but if not, that's pretty price for a pin and really doesn't need to be fully hardened like that. He can get an actual pin that will likely just need to be cut to length and/or drill on ebay for about 1/4 of that price.

Cool. Thanks for the input.

This machine was on a job, and he needed something asap. We should have him up and running tomorrow.