The Home Machinist!

wow .. forum is dead lately ... can't have that.


I tried drilling holes in this piece of alum .. matching the two existing holes on my machine.
I missed it by hair and had to oversize one of the holes. It just felt so "un-machinist" like.

I just held up the alum and made little marks under the holes and tried moving them to the
center of the piece. Like stated ... just missed.

I have heard of transfer pins .. but the holes aren't that deep. What are some tricks to doing
this. It might just be a matter of practice and i'll accept that but wanted to ask.

***

I did something to turn one of my endmill holders brown. I suspect it was pushing it
a little hard and overheating it .. but .. I was just cutting alum and was doing it all
day long. This cutter did require a lot of forcing ... but its weird.

I really like gathering these little tid bits of experience .. I just need someone to translate
them for me.

If the holes are threaded you can use transfer screws to mark the plate. These are hard sorta like set screws with a center punch point on one end with a small hex milled on it to screw them into the hole leaving the center point a little above the surface. Then place your material where you want it over the transfer screws. Then tap lightly with a soft hammer. This will give you center punch marks dead on location for drilling.

Its hard to tell by the picture in the catalog because they show the holder in which the transfer screws are inside it. One end unscrews and you remove how many screws you need, then put the cover back on. The other end (small end) is like a small hex socket to screw them into the hole. I think there are 6 of the same size screws in the holder.

http://www.use-enco.com/CGI/INPDFF?PMPA ... M=410-3008


Richard W.

The holes don't need to be deep to use transfer punches, they just need to be through holes. A good set of punches will have some to fit through internal threads.

http://www.harborfreight.com/28-piece-t ... -3577.html

On the transfer screws, I got caught in a pinch one time on a weekend. A drill motor, some tape, and a bench grinder made some good enough for one use. Chuck the screw up *lightly* in the drill motor using a little tape to protect the threads, spin it up and hit the end on the grinder.

Perfect? No. Close enough to locate the holes on a chuck backplate? Sho'nuff.

Small through hole in thin stuff? Mark on the material with a sharpie or layout die, use the ground sharp end of a drill bit through the hole to scratch a mark. grind the butt end, not the business end.

I was going top comment on the discoloration of your tool holder. Do you have some sort of acid in your coolant?

OR...


One time way back when I seen this discoloration come from the operators sweat. We figured he had to much acid in his system and everything he touched turned much the same color as your holder in the photo. The handles on the machine turned color. Do you eat a lot of tomatoes and hot peppers? That would be the only things I can think of, but I may be out in left field on this? Usually in the fall when people eat a lot of tomatoes from their garden they get acid in their system. Then at work they finish up a real nice looking part and set it on the bench or the foremans desk and the next day their finger prints are etched into the part from the acid.

Richard W.

I don't even need tomatoes!

_________________
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

ok .. thanks guys ..

it helps when you know what to google. Got all the scoop on the transfer screws including
some writeups on how to make your own. GOT to get some of those.
BTW .. its a blind hole .. so those would be perfect and necessary.

The acid tip was interesting ... I almost always wear rubber gloves .. which means NOT
all the time. I'll have to take note of that next time .. If I am getting sweat on the tool.

Again thanks .. thats one more baby step in the right direction ..

For the transfer screws I just use a bit of thread rod or a cut off bolt. I put it in the lathe and turn a point then cut it off, and repeat. I then just screw it in with the point outward and place the piece that needs to be marked over it and give it a light tap. Once you have the first one punched it will locate the piece so you can then do the other one. As long as you don't hit them really hard they come out with just your fingers, and I have never had one I couldn't get out after woods.
It's cheap and quick as who wants to run out and buy them and wait for them to turn up, you usually want the job done then and there.

Dave

Another way to do it with just bolts is to screw in 2 bolts, measure outside to outside, then subtract the diameter of one bolt and you have the centre distance. This works easy for 2 bolts that are the same size.

Dave