Laser tolerance - how much to undersize holes I'll need to bore?

I'm ordering the first parts I've ever had lasered. (It's the plates for the body of the ring roller in my other thread.) I'm used to the angularity of a cnc plasma cut edge, which is a lot in 1" plate (at least on my setup), so I for a hole I'll later need to bore to size, I'd usually undersize the plasma'd hole quite a bit. My perception is that laser is going to be a lot less bevel, so I can probably undersize the hole a lot less, leaving less material to have to remove with the boring head.

How little undersizing should I be able to get away with? The holes will be matched pairs between the two plates, but I'll stack them on the mill and bore them together, so they should line up. Would it be safe to undersize the lasered hole .100" on 1" plate? (I don't know anything about the laser, other than that 1" is their max.)

Thanks!

I would leave .100" per side to be safe. It really depends on who is doing the cutting. You could spec the holes to the laser cutter to not be bigger than X.XX" That way you know you're covered.

I would say that .080" to .100" is more than enough. A laser will cut to a much tighter tolerance than that but
if you're going to bore the holes having a little extra meat won't hurt. Are you sure that the place you're using
has a laser that can actually cut 1" material? There are machines out there that will do it but the majority of
laser cutters that I have seen top out at 3/4"...

What tolerance on the hole do you need - what goes in the holes? What does the supplier say they can hold?

We regularly bring in laser cut pieces thinner than that and .002" is the tolerance. You could also water jet in, 1" easy and no HAZ....usually more expensive though as it slower.

Mcgyver said:

What tolerance on the hole do you need - what goes in the holes? What does the supplier say they can hold?

We regularly bring in laser cut pieces thinner than that and .002" is the tolerance. You could also water jet in, 1" easy and no HAZ....usually more expensive though as it slower.

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The hole needs to end up pretty snug and in the right spot, but like I said, I'll need to put the plates on the mill to drill other features anyway, so I don't mind putting the boring head on to finish these.

This will be the holes in the housing plates for a ring roller. If you look at the diagram in post #9 of my ring roller thread, these holes are the places where parts #31 and #42 will mate. I'll be making those parts too, and the mating diameter isn't critical, so I don't need to nail the diameter, just the location - I can make the collars a snug fit to whatever bore dia I end up with.

on 1" water or oxy-fuel torch will give you less bevel than laser. It does make a difference in size of hole, bigger is less bevel (lasers dish more than bevel at that range), our plamsa -if leveled- holds better than 1/16 on 13/16 hole in 1"- .1 under should give you amble material for alignment and clean up. 1" laser is a beast.

The thicker the material the more out of whack the burn will be, just like with oxy/acetylene. You should be able to do okay with ⅛" undersize on the holes at your spec'd plate thickness. The steel can be a little nasty (hard, etc.) on the cut surface sometimes too, so it helps to leave a little meat so you can get solidly under any skin effect on the first cut.