Originally Posted by kibble
I've been playing with the Deep Throat Metal Hand Punch
from Harbor Freight. It appears to be a knockoff of the Roper Whitney No. XX seen on this
page. If the tooling for the Roper Whitney model fits this tool -- and pictures suggest that it might, then this tool may be able to punch slots. So far, though, I've only punched round holes.
I'm glad I bought the base
; it makes it easier to use, but it needs to be mounted to a board; without it, the tool just tips over onto its nose. I attached the tool to the base, and the base to a piece of 5/8" plywood 5" x 8" with some 1" screws and fender washers. I didn't do any finishing to the base board other than file the edges to knock off the splinters. Here's how it looks mounted:
Click images to enlarge.
For size reference, the slot on the depth gauge is 3" long.
The manual assures us that everything we need is included, but there's a 2.5mm Allen wrench needed to tighten the set screws; it's not in the box, nor is it on the parts list. If you go to Harbor Freight to get this, buy a set of metric Allen wrenches at the same time.
I installed the 3/16" die set. I tried the punch on scraps of the types of steel I've been using for parts -- some .022" galvanized steel, an old computer case (.028" steel powder-coated on both sides), and some .031" stainless steel. The punch went through all of them. The force required depended on the material. The painted steel was easiest, probably because of the paint acting as a lubricant. The galvanized was almost as easy. The stainless steel was tougher, and I don't think I'll want to use this punch on that material. The stainless steel may have dulled the punch in a single use, because holes were just a little tougher after that. I confess that the instructions say "mild steel", and stainless isn't mild steel. Any damage done to the die set is clearly my fault for pushing it beyond its specified use. But that's just what research does.
There's a locator point on the tip of the punch, so I can locate holes precisely; once the punch is positioned, I just a push on the lever arm, and I have a hole. "Push" means "apply some pretty healthy pressure".
Here's a picture of the resulting holes in the test pieces:
The material on the left is .031" stainless steel; in the center is .028" powder-coated steel; on the right is .022" galvanized steel
I also tried punching 1/8" polyethylene, and it did just fine. The hole was smooth and very clean.
The dies come grease-coated and packed in clear wrap, which makes me suspect they need corrosion protection in the humidity of south Florida. I made a small container for them in my tool chest and I'll keep a grease rag over them so the atmosphere in the box is oily air.
The punch takes more initial setup than just slipping a drill bit into the drill press. But if I'm using a standard size hole -- I generally use 3/16" -- then I can just leave the punch set up with the 3/16" die set in it. It can sit on a lower shelf, ready to pull into action whenever I need holes.
I like the cleanup; there isn't any. I guess when I've punched enough holes, the slugs will start to fall out of the bottom of the die, but that's still almost no mess. I'll brush a little dab of grease on the punch and the die when I'm finished each time to keep them lubricated and rust-free.
If I just use it to make the holes at the end of slots, it's an improvement over drilling. The resulting holes are very clean and smooth-edged, and don't need any filing until final cleanup of the parts.
I made a quickie bracket for a temporary system I was building, and needed holes in a piece of bent sheet metal. I marked the holes with a center punch, stuck the metal in the punch a couple times, and BAM!, BAM!, there were holes, perfect holes, right where I needed them, with no finishing required. I've never made holes so quickly and easily in my life. Oh, I like this tool.
The verdict so far? While this is a handy tool for surprisingly low cost -- especially on sale -- it isn't the total answer to making slots. With the standard tooling, I'll still have to use the cutoff tool to complete the slots. The punch makes the process easier, but it doesn't produce instant slots, so I'm not ready to call it the "solution".
If it can accept the Roper Whitney tooling and punch slots, it could be the answer I wanted. I'll research that this week.
Even without that capability, it's a keeper.