Undersizing boiler plate formers

[Deleted]

Hi Folks,

It would seem reasonable to expect a boiler plate former to be smaller than the finished plate size by the thickness of that plate. However, I have read of a former for a 1/8" boiler plate being only reduced by 3/32" on each flange side, as an allowance for reduction taking place during hammering in the flanging process. The plates' section thicknesses do change somewhat as they are being worked, and then they are finally filed a bit to finish, but can anyone comment on this?

Thanks,

Dave

[jma1009]

Hi Dave,

I think 3/32" reduction on former size for 1/8"/3mm flanged plates is far too much. 1/64" either side reduction would work out fine in my experience. Also depends how you wallop the flanges and what the formers are made of.

Cheers,
Julian

[Deleted]

Hi Julian,

Thanks for that.

Best wishes,

Dave

[gwr14xx]

It also depends where the flange is - if it is carefully formed and straight, the thickness should not alter. If it is on the outside of a curve, the thickness will increase a little - conversely, on the inside of a curve, the flange will get stretched and therefore be a little thinner than the original plate.

[ettingtonliam]

Are Dave and Julian talking about the same thing? When I read Dave's posting, I thought he was talking about making the former 3/32" smaller each side than the overall finished size of the plate, because his 1/8" plate can be expected to end up as 3/32" thick flanges after hammering and cleaning up. Julian seems to be talking about making the former 1/64" smaller than the inside dimensions of the plate, between flanges. Not the same thing at all, to me.


Richard

[Deleted]

Hi again,

Sorry about my initial post being unclear. The plate is 1/8" thick. The final width between side sheets, that is the final width across the flanges of the plate, must be X. So initially it might be thought that the former that the plate is folded over must be X - flange thickness, so for the two flanges on either side of the plate width, that would be X - 2 times flange thickness. In this case, that would be X - 2 times 1/8", = X -1/4". What I have read however, is that this would be reduced to X - 2 times 3/32", = X-3/16". However, this change from the 1/8" flange thickness to a reduced 3/32" is assuming that the beating during folding actually reduces the thickness of the plate on the flange from 1/8" to 3/32". If the plate does not reduce that much, that will necessitate an extra amount of filing or milling, to make the dimensions of the plate meet the required size.

Thanks for your help and patience,

Dave