drilling templates

[toyotaj]

I am a novice fabractor, welder, etc.
I am building u-bolt flip plates for my 4x4 rig and my buddies rig. I am drilling 1/2 diameter holes in 1/2 steel plate. Is it bad technique to use a completed plate for a template to drill through? I was even thinking to tack the template to a fresh plate before drilling. Is this an ok practice? I would normally use trial and error to determine something like this but I am bored at work.
Thanks
J

[OlPilot]

Why don't you use a transfer punch to mark the hole centers through a new part on to the material you need to drill? That way, you don't risk wallowing out the holes on a good part. Use a drill press, if you have one.

Transfer punches are cheap enough. Even a Harbor Fright set would work OK for this purpose. But I can't recommend their Chicom drill bits.

[Aaron]

Pick up a set of transfer punches. They are inexpensive and very handy.

You place the template and the material back to back, and place the appropriate transfer punch in the hole (they are sized in increments of 1/64" dia.) and smack with a hammer, leaving a dimple for your lead drill.

[toyotaj]

Ahh ok. A transfer punch. I will have to pick up a set. Oh and I am using a drill press. A HF benchtop.. So far it seems fine for my level.
Thanks
Guys

[Franz]

The problem with templates is that they wear. To overcome the wear on the template it must be overbored to accomodate a drill bushing. Then you will have a template useful for hundreds of drilling operations.

[fla jim]

Originally posted by toyotaj
Ahh ok. A transfer punch. I will have to pick up a set. Oh and I am using a drill press. A HF benchtop.. So far it seems fine for my level.
Thanks
Guys
J;
From your reply. I kind'a get the feeling your not sure about transfer punches.
Here's some more stuff from the Magic Garage.
Transfer punches come in drill bit sizes, the most common set is fractional from 3/32" to 17/32", by 64'th. They also come in wire guage, letter and metric.
"Carefully" layout and drill your first plate, and mark it master. Use it for the rest. clamp it to the next plate, making sur it lined up good. Tape the proper size transfer punch insert it into the drilled hole. Tap it lightly with a two or four once hammer. You just want to mark the location for the hole. Repeat for the rest of the holes. Remove the master plate, and center punch the marks.
for easy drilling drill a pilot hole about 3/16". Then drill the proper size hole. Harbor Freight, Wholesale Tool and other supply shops have them.
Here's a photo of a fractional set

[fla jim]

Here's a closeup
Remember if you use them strike the punch gently, just to make a mark. Then go back and center punch it. Make you center punch mark as wide as the webb of the drill bit you will be using. This is so your drill bit won't wander.

HF Expert Jim:dizzy: