How to mark and transfer predrilled holes to a blank piece

[Lar]

New to this site and the world of machining. I would like to know how to transfer the already drilled holes in a machine table to a block of steel to be used in my mill drill. This to raise the table so small work is closer to the mill head to prevent as much deflection as possible when milling. There are 4 holes in the table.
I hope I am explaining it right. I know there are transfer punches but for this purpose,but they don't seem to work in this application.
What methods do people use to do this?
Great site!
Lar ???

 

[Dave G]

I'm assuming these are blind holes. If these holes are tapped, you can use transfer screws, which are basically set screws
with a point on the end and a small hex to help install and remove them. They can be purchased or you can make them from set screws. To use transfer screws, you just screw them into the holes with the pointed end up, allow the point to stick up
above the surface slightly on all the holes you wish to transfer. Then orient your workpiece on top of these screws in the correct position and lightly tap the workpiece with a mallet to leave small indentations on the workpiece. Remove your workpiece and deepen the indentations with a center punch. You should have good success with this method if they are tapped holes. I hope this helps. Good luck and work safely. Dave

 

[Lew Hartswick]

Maybe I'm just a bit (what is that word ) but I always do that by honest to gosh
dimensioning. Measure accurately and layout just as accurately. Transferring by
any physical means leads to requiring more "slop" in the holes. Now in this case
(of the OP) I don't think it will matter much.
...lew...

 

[kjk]

I'm very new to machining, but what I would do is make a template from scrap - whatever easily worked material you have around. A bit of masonite, mdf, scrap aluminum - whatever.

I would measure carefully, mark out and drill the scrap. When you have achieved a good layout on scrap, then use transfer punches to mark out, drill etc. the work piece. Clamp the template securely to the workpiece. As each hole is drilled into the workpiece, tighten down a fastener through the template. Work slowly and deliberately and check your work as you go along.

Essentially I'm suggesting you do the job twice - if the material you are using is cheap and has no other work invested in it, you may want to save the effort.

Welcome to HMEM - it's a great forum.

 

[mklotz]

The woodworkers use "transfer points" (think transfer screws sans threads) to transfer dowel hole locations from one part to another. If you can find some to fit your holes, use those. If not, make your own. Alternatively, sleeve the commercial ones to fit your holes.

http://www.amazon.com/dp/B00004T82N/?tag=skimlinks_replacement-20

 

[Metal Butcher]

You could use a center finder and zero out your hand wheel at the first hole location. Shift over and center on the second hole and note the distance of movement on your calibrated hand wheel, DRO, or dial indicator, and so forth on the other two. This will give you a more accurate way to locate the holes you need to drill in the plate.

Without a picture its hard to say what method would work the best, or at all.

-MB

 

[Ken I]

If you do it by measuring - don't forget to measure the diagonals as well.
Otherwise you might end up with a paralellogram error (and of course it's possible the holes you are transferring are also not square).

Welcome to the forum Lar.

Ken

 

[Metal Butcher]

Another idea is to snug in 4 bolts with a shoulder, take measurements, and subtract half the diameter of both shoulders on the bolts. Checking for squareness as suggested by the previous poster is a good idea and it could also be accomplished using this method.

-MB

 

[Paulsv]

I found about 6 or 8 sets of transfer screw sets in different sizes in the tools I got from my dad when he died. He was a tool and die maker. They are very handy for a situation such as the OP described, where you can't get both parts up on the mil table to drill mating holes by measurement. I have found them to be extremely accurate if used carefully. I don't know that I would use them in a really critical alignment, like a cylinder head to a block, if there was another way, but I think that, for what the OP is doing, they are a lot more accurate than any of the other methods suggested in this thread.`The trick in using them is to get the mating part accurately aligned over the part that holds the transfer screws, and to do it without making a bunch of marks or scratches on the bottom of that part with the transfer screws while you are aligning it. If done properly, you end up with just one clearly identifiable mark at each transfer screw, and then it is quite accurate.

 

[Lar]

Thanks for the ideas. I am going to try measure as i need practice. I am also going to try and make some set screws.
Lar