[powerrodsmike]

I needed some 3/8" x .035" slugs to fill some holes in a set of splash pans.
I know I could have backed up the holes with aluminum or copper and pounded some mig welder wire in it but I have to do things the slow stupid way.
So I made a punch.

I take a piece of steel 1/2 thick and put it in the vise on the mill. drill a hole 3/8" diameter.

I get a piece of 3/8"drill rod and sharpen it with a slightly angled concave end. I just hold it at a right angle to my bench grinding wheel, slightly above center. Put the drill rod in an end mill holder and install it in the spindle.

Lay a piece of sheet metal on the metal in the vise and punch away. A quick jab with the spindle works well.

I have used a setup like this to punch up to 7/16 dia in .035 steel. It works well on other materials like rubber and sheet teflon and plastics. I have been doing this for a few years and have not noticed any adverse effects to my mill downfeed mechanism or spindle bearings. I don't think I would use it to punch holes all day every day though. I'd buy a real punch. I never tried it in a drill press, but I'd imagine it would work. I'd add some weight to the quill to make it more hammer-like.

BTW- if anyone knows that this will mess up a mill, please post it and I will erase this thread. I talked to a couple of guys who didn't seem to think it would, but they are no final authority on anything.

I mainly use it to get the slugs for filling drilled holes in firewalls and other sheetmetal. I usually make a slug slightly oversize and ream the hole to fit the slug real tight. That way I only have to fuse the metal with my tig. Makes the bodywork a little less afterwards

[powerrodsmike]

Heres what I do with them.

I find it is easier to fit the hole tightly to the slug with a tapered ream and fuse the slug in with the TIG. Very little filler rod is needed. A couple of taps with a hammer and dolly then some grinding and very little bondo is needed to finish.
The weld on that 3/8" plug in the pic was done with a .040 tungsten with about 30 amps.

Sometimes for the bigger holes like in firewalls and radiator supports I go to the sheetmetal shop and fish around in their slug bin. .
Later, mikey

[oldred]

Hard way? Not at all, in fact it's a good idea as it will make this job a lot easier to do with out warping the panel from all those plug welds

[Kevin45]

BTW- if anyone knows that this will mess up a mill, please post it and I will erase this thread. I talked to a couple of guys who didn't seem to think it would, but they are no final authority on anything.

One thing you may want to do someday is check the tram on the head. After periods of drilling and milling, the vibration can move the head. I do not know what type of mill you have but on the better mills the tram will change. On the cheaper mills I know it definately will. How do I know? I have run mills almost all my life. If you do not know how to check the tram, you will need a dial indicator, and a longer extension for the indicator. Center your mill table with the quill (remove the vise first) and set the indicator so it will reach the back of the table then swing it around 180 degrees to see if it reaches the front of the table. Adjust accordingly. Now that it does, touch the top of the table and set the indicator at "0". Swing the indicator in a 360 degree circle. All four points (north, south, east, west) must read zero. Adjust you head on the mill until it does. Most mills have 4 bolts in the front to rotate the head and usually three on the side to tip the head. Make sure they are tight after adjusting. After that, remount your vise and indicate it back in and you are on your way.

Kevin

[powerrodsmike]

Thanks kevin-I was hoping you would see this

My mill is an '85 Sharp TMV. It is an import, but seems fairly stout. It doesn't have a knee like the newer tmv's do, but the head does turn 45* either way. I actually do check the tram before I do anything that requires some degree of precision. Also I check it whenever I return the head to a vertical position after using it on an angle. The tapered pin that is supposed to register the head is all wallowed out and doesn't work anymore. I have an old Alina .0-.015" test indicator that I use with a 6" extension.

I was concerned that I was going to mess up the spindle bearings or gears in the downfeed mechanism from the shock of punching. I wouldn't want to tell folks to do something that would tear up their machinery, just because I didn't know better.
thanks, mikey