Question on suitability of plasma for saw disk arbor hole

[motoguy]

A customer called today, in quite a bind. He has an Italian masonry saw, with a 40mm arbor. He didn't elaborate, other than to say it would be a great help if I can enlarge the arbor hole on certain specialty blades from 1" (commonly available size) to 40mm for his saw. If I can do this, he will have me re-size the hole on all his incoming blades.

I'm curious if my Bulltear table (6x12 w/ 85a PowerMax) can cut a concentric-enough, clean-enough hole for use on a masonry saw blade? I do not know the thickness or composition of the blade, however he is going to have several scrap/used blades available for me tomorrow.

If the table/process is suitable, do you have advise on jigging? I have not worked with jigging on the plasma table.

I will try to hook him up with a laser or water jet setup, if plasma is not suitable. One way or another, I would like to assist him

[acourtjester]

You can setup SheetCam to use the center as a starting point (X zero Y zero) put the blade on the table and move the torch over the hole. Move it down very slowly and allow the torch tip as it goes into the center hole to center the blade now zero the X and Y dro's. Move the torch up and put a small sacrifice 18 ga. scrap on the blade for the torch to use as a touch off. Make a plan to cut the 40 mm hole with X zero Y zero as the center load the plan and start it up.

[Capstone]

I think that while you may be able to get very close, the repeat-ability question remains. The accuracy required to ensure that the completed saw blade spins safely in the saw is suspect. I would not attempt it.

Wouldn't it make a helluva-lot more sense to have the owner get the arbor machined to the common 1" spec?

Some of my best future customers will be the ones I sent elsewhere for the right service.

[jimcolt]

Better suited for someone with a simple Bridgeport type milling machine. Locate the hole with a 25 mm diameter tool , put in a 40 mm end mill and drill!

Jim Colt

[motoguy]

I think that while you may be able to get very close, the repeat-ability question remains. The accuracy required to ensure that the completed saw blade spins safely in the saw is suspect. I would not attempt it.

Wouldn't it make a helluva-lot more sense to have the owner get the arbor machined to the common 1" spec?

Some of my best future customers will be the ones I sent elsewhere for the right service.

Once I meet with him today, I will try to get details on why he needs this done. I agree that it would seem to make more sense to modify the machine to accept the different blades, but there may be some reason why that is not feasible. Maybe I misunderstood, and it's some sort of an emergency one-off thing that he needs done today, vs more of a long-term plan.

[msimpson99]

First, I think if you have enough blades to practice on you can probably get it dialed in. That said an arbor hole needs to be machined. You will never get it close enough to stop wobble. While the CNC plasma has its own set of issues when cutting things like this, even a drill press could be problematic. Even laser cut and waterjet cut will have the final dimensions milled.

[matze-atze-sch]

I would make the hole on a lathe.
Are in the blade holes for pins or only the center hole?