metal parts

[georgebarr]

I didn't know this when I was in the process of building my CNC metal machine, but I just found out that my local metal supplier can use big shears to cut mild steel plates to almost any size and use big punches to create holes on the plates. With the punches, I do not have to take long hours drilling holes that might not be in the correct spot or other problems. Had I known this, I would not have wasted a lot of time. The price seems to be right. I was quoted $16 for a 12" x 12" x 0.25" with 4 holes (punch and material). For $8, I can get a 6" x 6" x 0.25" with 4 holes (punch and material). I still do my own MIG welding since it cost $58/hour for the metal shop to do it. Their EDM/Plasma cutting machine is $70/hour with a $48 minimum. So EDM and MIG welding cost too much for me.

What other services do metal shops offer. Maybe it is possible for me to just take it to the metal shop and pay them to do it for me. However, the problem is I don't know what kind of services they offer. Any ideas?

Update: I was also told that all punching will warp/bent the part. The one person I spoke with says it will warp it at about 1/32". Is there a way to punch and not warp the part?

[Ken_Shea]

George,
Depending on where these plates are used it may be that this possible warping may not be an issue, also manually punched holes are not going to be particularly precise in either location or diameter. You factor all this with weld pulling and you end up with a part that is not precise at all. If the part requires precision it should be made/machined with this in mind. Manual shearing and punching along with welding just do not lend themselves to precision. Not everything on a CNC needs to be perfect, great if it is, but this is just not realistiic for a home shop DIY machine. We get all cought up with this +-.001 stuff but in reality how often is this really needed. If your intended products will require that or less then a home built machine is just not real likely to fill your need.