Welding a cast iron tool (Roper-Whitney XX punch)

[Sodo]

I bought this cheap copy of a Roper Whitney XX deep throat sheetmetal punch. Roper Whitney item costs $250, this was $60. It doesn't work because the punch can't go into the hole on the die. I replied to the eBay seller with pics of the defect and they just returned my money, that was Apr 27, 2013. Here it is 2 years later and I was about to throw it out but thought maybe I can repair it (that is my problem throwing stuff out).

I was thinking of making a LONG cut (at a shallow angle on the yellow line) re-aligning it, and brazing it back together. Not sure how best to cut it either.

Can I heat it up and arc weld it? Will it retain the re-set alignment? Its about 1 1/4" thick, and you can guess the other dimensions from the penny (is 3/4").

I'd be willing to spend an hour on it before tossing it.

 

[CalG]

rebore it and add a bushing

Welding chicom CI is a fools mission. Who knows what is under that paint.

 

[Leejohn]

Ream punch hole just a hair, put set screws at a 45 deg on both sides on the back side. Use the set screws to center punch. If you go to big with the ream then put a 3rd set screw in the front. The trick here is not to go to big with the 1st ream job.

I have the Roper Whitney one and got it in the mid 70's. Use it often, some of my dies have broke on the adjustment end. Other then that it has been a good one. BTY (I just have to do this) I got mine for free. Had a buddy that worked there, and come to think about it I think my mother worked there in the 50's.

 

[Sodo]

If I can cut & weld in an hour; I think that's worth the time spent on this free sheetmetal punch. I have the tools for that repair (I think). I'm interested in the challenge. If it will punch a hole, and also withstand as hard as I can squeeze on the levers then thats good enough.

I was thinking of brazing or silversolder (?). But if it can be arcwelded that would be the quickest.

Thats a good idea to center the die with setscrews......but if it can be welded it will work as designed with all the quick-change punch & die sets.

 

[Shield Arc]

Before cutting and welding, I'd try a little heat shrinking first.

 

[petegoud]

Before I spent any time dealing with this, I'd ask myself how much is my time worth? Chances are you've already exceeded that.

 

[Baby Grand]

I'd try to salvage it.
You've nothing to lose, save the time, and if the time is spent learning, then it's time well spent.

My concern with welding is that you'll first need to V out the 2 pieces, resulting in sections that vary in thickness along their lengths.
Also, the weld will be running at an angle to the direction of the machined bores.
You'll need to get two machined axes aligned and collinear, or you'll be right back where you started.
That means controlling the distortion in 3 dimensions - the welding equivalent of drawing on an inside straight.

I think your idea of brazing may have a much better chance of achieving the alignment that you need.
You can get the alignment right by positioning the tool in the die while brazing and post braze distortion should be very small.

Over-boring & bushing or using different set screw orientations, as described by CalG & Leejohn, would be my second & first choices.
If you can get the tool into the die with the present set screw removed, then using different set screw orientations should work.
If you can't get enough correction that way, then over-bore & bush, if you have a milling machine that's up to the job.

 

[Ed of all trades]

Just for your info, I got one of these from Harbor Freight for Under $20 if I remember right. It was about 10 or 12 years ago but it is worth checking it out. I used it doing HVAC work for 4 or 5 years and no problems.

 

[Sodo]

Smaller "no. 5 jr." punch is currently about $50 and they're everywhere. I bought one about 20 yrs ago for $45 and it works great. This is the "XX" size (about double of the "no. 5"), they cost more.

Undoubtedly the internet side of this project will take more time than an hour! Declining methods that require tools I dont have will take an hour in itself but thats part of the fun I guess.

The lower leg is about 3 inches and it has to "shrink" .034 inch to come into alignment. There is some slop allowed ( perhaps required).

Shield do you think it can be shrunk .034"? If it can be done with 1/8" rods I'd consider it but thats my max as you probably know. It would be quick, but Seems to me it would "misalign by design".

 

[Shield Arc]

Shield do you think it can be shrunk .034"?

Oh sure, I moved beams, and pipe a foot or more. The problem with heat shrinking, and weld sequence to control / correct distortion is the amount of heat! Not the location, any first year welder knows where to put the heat, the trick is how much!