I’ll be cutting 18 or 20GA galvanized steel.
What is the minimum circle(or hole) diameter when using the Razorweld45 on the XFPro with a water table?
1/4" ? 3/8" ?
Thanks!
The rule of thumb is the minimum hole size is equal to the material thickness. in the case of 20 ga (.0396) your minimum hole would be a single peck point approximnetly .05" (see in picture)
It depends on whether you want an ACCURATE hole or just a hole about the target size. And does it have to be round, or merely a hole.
And bear in mind, the edge of the hole will be hardened by the reaction to the cutting process and, therefore, will be difficult to drill to size.
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@TomWS i have a question about that hardening…i have always assumed that doing any drilling or other type machine work to a plasma cut material would be a pain due to the hardening i assumed was occurring. I cut some brackets out of 3/8 mild steel and had to modify my holes with a drill bit and then countersink the surface. much to my surprise the metal drilled and countersunk in a manner to me that did not act look or feel any different from simple hot rolled mild steel. have you experienced the hardening effect?
I haven’t noticed that drilling out plasma cut holes is anywhere near as hard as drilling actual hardened steel. Tapping plasma cut holes, without drilling them, is a different story. I pretty much destroyed a 3/8 Irwin tap doing the holes for my belt grinder build, because the holes in the DXF were on size for tapping. On future projects that require tapped holes, I will be cutting the holes undersized and drilling them to size before tapping.
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I have read some people have problems with case hardening and some don’t. I think case hardening ranges from .010-.015 thick. Some use Carbide or Cobalt for drilling.
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At the shop we machine flame cut t1 steel. Then machine flame and plasma cut parts all the time good drill bits and a solid drill press with plenty cutting oil it all good.
The short answer is yes, I found the walls of plasma cut holes to be harder than the normally drilled steel and, due to the non-roundness of the holes, the drill bit would catch and/or drift off center. Surprised by that effect I did research on the Web and found articles describing what caused the hardening and accepted that.
However, I will admit my ‘machine shop’ is probably not on par with the folk who do this all the time and my drill bit selection was limited to China Inc. HSS drill bits. I have selectively replaced drills with Cobalt bits, but continue to practice ‘center punching’ holes where I care about accuracy of the diameter simply because its completely reliable.
From the 'horse’s mouth (or Colt’s in this case):
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@TomWS has for sure the safest way to accurately drill holes. Keep in mind if you want to plasma cut a pilot hole. Don’t cut a .25 hole to drill a .25 hole. A good example of you need a accurate hole say .5 cut a .25 hole with the plasma leaving plenty meat to drill.
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@TomWS thanks for that link. good information. i guess i was just fortunate either in amount of material i was drilling out or have better drill bits than i gave them credit for. i like your idea of obtaining accurate holes when necessary.