Athearn Underframes and MT couplers

[dmidkiff]

Really appreciate the info guys. And Pete, I totally get the  , I was working on MTL boxcar frames and couldn't get more than a 1/4 turn before it stopped. I said F-it, gotta try to get more torque than my hand provided.

Sounds like I'll be looking for a nicer tap than the MTL ones, especially since i lost my last one, using a lubricant and maybe getting a T wrench to hold the tap.

Doug

[peteski]

Really appreciate the info guys. And Pete, I totally get the  , I was working on MTL boxcar frames and couldn't get more than a 1/4 turn before it stopped. I said F-it, gotta try to get more torque than my hand provided.

Sounds like I'll be looking for a nicer tap than the MTL ones, especially since i lost my last one, using a lubricant and maybe getting a T wrench to hold the tap.

Doug

Doug, if the tap is really getting stuck in the hole, you might want to drill the hole using the next size larger drill bit. The threads will be little shallower, but it will still hold the screw.  Also a T-handle seems a bit of an overkill for a 00-90 size tap.  When I had problems with not being able to get the tap tight enough in the pin vise (it would spin in the collet), I ground either a flat spot on the tap's shank, or even ground it down to a roughly square shape.  That way It will positively lock in a pin vise's collet.   The MTL tap should be perfectly adequate for tapping either plastic or metal underframes.

[jagged ben]

Pin vises are not for drilling metal.  You want something like this:
https://www.amazon.com/CAIDU-Semi-automatic-keyless-Drilling-Set（∅0-8-3mm）/dp/B071XMFXMC/ref=asc_df_B071XMFXMC/

Try googling 'jewelers spiral twist drill' for other options.

I can drill a metal underframe in about 10secs with mine.

Either that or invest in a drill press setup for your Dremel or similar.

[MK]

Fixed link:

https://www.amazon.com/CAIDU-Semi-automatic-keyless-Drilling-Set（∅0-8-3mm）/dp/B071XMFXMC/ref=asc_df_B071XMFXMC/

[jagged ben]

thanks

[nkalanaga]

Tom:  I also use Labelle oil.  It's handy, and seems to work as well as anything else.

As the others said, never tap with a power tool, at least for consumer-sized taps.  If you're tapping  bolts for a full-size locomotive, I imagine you'd have to use a powered tap, but for ours, you're almost certain to break them.

The only time I've watched a machinist tap a "large" hole, for a quarter-inch bolt, he did it by hand.  He drilled the hole with a bit in a lathe, then put the tap in the lathe, and turned it in by hand, just like we'd use a pin vise.