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View Full Version : Will an annular cutter cut through weld?



Jimno2506
08-17-2009, 01:06 PM
Machinists,

My brothers have several steel pieces that have a pin welded through a hole. The pins are worn from years of rubbing on a bushing. The new parts are $70 each and I need 24 of them (yep, it's the planter again). I was wondering if an annular cutter on a slow speed drill press would cut the weld so the pin can be removed and replaced. The weld is on a 1" dia pin. The pin is proud of the arm and not plug welded, just welded on the OD. This would cut the weld off with minimal grinding. I've use annular cutters quite a bit, but never on a weld.

I thought grinding would be cheapest, but take forever. They don't have a milling machine handy and I'm too far away to do any good.

Any other ideas are greatly appreciated.

Regards,
Jimno

recoilless
08-17-2009, 01:33 PM
Well, I'd ask what type of rod/wire was used in the original weld as well as the base metal. There are rods designed to be machinable as well as some that set up glass hard. This might help you with getting a better answer. I should add that annealing the area welded might help out the cut also.

websterz
08-17-2009, 02:46 PM
Since the pins are toast anyway I would use a scarfing tip on the old blue wrench (cutting torch) and just skim them off flush, hit with a grinder, and drive the stubs out with a punch . Fastest way IMHO.

tattoomike68
08-17-2009, 02:49 PM
Take a torch with a fairly small tip and wash away the welds fast so the base metals dont get very hot so you can see the separation. With some practice you will not even need a grinder.

djc
08-17-2009, 03:00 PM
...I was wondering if an annular cutter on a slow speed drill press would cut the weld so the pin can be removed and replaced.

By 'annular cutter', I assume you mean Rotabroach (magnetic drill) cutter.

You've probably worked this out already but these are sized to cut a _hole_ (not a slug) of a finished size. If you are intending to let the 1" dia pin go up inside the cutter to guide it, you need something with an ID of 1", which you would have to find by trial and error. You may need to trim the 1" pin quite short so you have enough depth inside the cutter so it doesn't bottom out.

Depending on the size of the weld, you might still have to do some grinding if the OD of the cutter is insufficiently big to remove it all.

Saying this, if the assembly the pins are on is portable, I'd use an abrasive chop saw and just run the blade down flush with the outside of the section from which the pins project. Well done, this will be your weld prep for the new ones. If you can't use a chop saw, use one of the thin blades meant for stainless on a 9" grinder.

Jimno2506
08-17-2009, 04:14 PM
The weld is on the short side of the pin.. The pin probably sits up about .25" above the plate. I figgerd a 1-1/4" would have approx .125" thick walls and would take care of a large portion of the weld.

Being that these welds are very flat and there isn't much sticking out, I'm afraid the chopsaw blade will simply flex around the weld. Probably have to start with a hand grinder to give it a flat place so it doesn't slip off.

Another question is what kind of steel the pins would be. I would think it is pretty good steel. It's not hardened as my 60deg file cut a small v in the end. It's harder than 1018 but doubt it's high carbon since it was mig welded.

Any ideas...perhaps its similar to Category I pins or trailer hitch pins...any idea what those are made of?

Regards,

Jimno

Carm
08-17-2009, 04:28 PM
I'd wager the pins are 1045, if they're cold rolled.

I wouldn't use a Hougen or Jancy style cutter without a totally rigid set up, and I'd hold my tongue sideways if I did.
It's hard on the wallet when the thing breaks from the git go. Can be done, but hard/soft areas from HAZ are hard on the edge.

camdigger
08-17-2009, 08:53 PM
I dunno the exact steel type, but I don't think they're a high carbon steel, probably more in the range of a mid range carbon steel.

It was mig welded to a steel part right? probably similar metallurgy. Some of the material descriptions that show up in a google search read spring steel, A3 If pressed I say similar to Grade 8 hardware.

How good are the folks in question with a gas axe? As mentioned above cutting the whole pin and weld off with a torch can be a quick and effective way to remove the parts. I know you can get very close to the bottom surface of the weld, but I'd recommend leaving a little weld and dressing it flat with an angle grinder.