Ok, it is chassis whole time.........?

[StratTone]

I'm wanting to use a punch and it seems that Greenlee seems to have good reviews. I'm gonna need a 3/4'' and a 1 1/16'' round punch but I would also like to punch my transformer square hole for the MM tranny. Where are the best deals? I've checked the bay and seen many many many but a lot of them didn't have all the parts.

[mark norwine]

Greenlee is *the* company.

Go to a large electrical supply house. That's where the bulk of Greenlee tools are used and where you'll get the best deals. Better still, find a friend who's an electrician and have him buy it. He's likely to get a better deal than you will.

That said, be careful how you order these. If you waltz into an electrical supply house and ask for a 3/4 punch, you'll likely be sold a "3/4" trade" punch....translation: It's designed to punch the hole needed to mount a connector that fits a piece of 3/4" condiut. In other words, a 3/4" trade punch makes a hole much larger than 3/4".

You need to be very clear that you want a 3/4" punch that makes a 3/4" hole. As silly as that seems.....trust me on this!

And don't be surprised if the supply house doesn't have it in stock & has to order it. "Trade sizes" [what you DON'T want] is 90% of what they sell.

Hope this helps.

[rooster]

To clarify, the reason the 3/4" punch is much larger than 3/4" is because pipefitters refer to the INSIDE diameter of the pipe, not the outside.

rooster.

[StratTone]

Greenlee is *the* company.

Go to a large electrical supply house. That's where the bulk of Greenlee tools are used and where you'll get the best deals. Better still, find a friend who's an electrician and have him buy it. He's likely to get a better deal than you will.

That said, be careful how you order these. If you waltz into an electrical supply house and ask for a 3/4 punch, you'll likely be sold a "3/4" trade" punch....translation: It's designed to punch the hole needed to mount a connector that fits a piece of 3/4" condiut. In other words, a 3/4" trade punch makes a hole much larger than 3/4".

You need to be very clear that you want a 3/4" punch that makes a 3/4" hole. As silly as that seems.....trust me on this!

And don't be surprised if the supply house doesn't have it in stock & has to order it. "Trade sizes" [what you DON'T want] is 90% of what they sell.

Hope this helps.

Thank you. That makes sense. When I was looking on the bay it seemed unclear as to what size they were talking about.

[mark norwine]

To clarify, the reason the 3/4" punch is much larger than 3/4" is because pipefitters refer to the INSIDE diameter of the pipe, not the outside.

rooster.

The size of a trade punch is based solely on the hole needed to mount a connector suitable with the conduit, ID vs. OD notwithstanding.

A 1/2" trade punch makes a .875" hole
A 3/4" trade punch makes a 1.125" hole
A 1" trade punch makes a 1.375" hole
A 1-1/4" trade punch makes a 1.750" hole

etc.

[mark norwine]

Oh....one more thing:

Don't buy a used punch. They may be made from hardend tool steel, but they do, in fact, dull. Anyone selling a used punch [Ebay, etc.] is perhaps selling off old, dull tools. The mess that a dull punch makes can't be easily cleaned up.

Buy new, freash tools.

[Wakarusa]

Trade punches also differ in whether they are making standard size holes for plumbing fixtures or electrical fixtures (because, natch, the outside diameter of the connectors is different).

Greenlee is definitely the Rolls Royce of punches and they're priced accordingly. Cheaper alternatives are available either used or from manufacturers like GB. The big differences are a) how clean the hole is (sizing, burrs, etc.) and b) how many holes you can make before it wears out. Another good alternative is a Unibit but only if used in a drill press on a well clamped workpiece.

For your transformer hole are you looking to make a several square inch hole in a single stroke? If such a punch exists it'll cost you dearly -- even a machine tool shop running a turret press will make these kinds of holes with many strikes. Consider a saw or grinder and some follow up work to clean up the edges.