Warped chase 6x9 Sigwalt

Ragpicker Press
on 1 Oct 12 (16:16)

One pair of opposing corners are high or the other pair low.
It’s out of flat by just under 1/16th of an inch when the opposing corner is down flat

1/ How does this happen?
(Students & members here tend to over-tighten quoins
though I think that usually leads to cracking the chase.)

2/ How can this be corrected?
Surface grinding?
Warping it back in the opposite direction?
The chase is cast iron and I’m concerned
about fatigue or other cracking

Has anyone on the list dealt with this problem?

Thanks.
Calvert
KC

portraitpainter
on 1 Oct 12 (22:44)

I have a slightly warped one for a press similar to a Sigwalt. I tried sanding it down by glueing a sanding sheet on a flat surface and rubbing the chase around on it. I could see where the low points were by the shine on the metal but I never seemed to get it flat. I finally ended up just shimming it a little. I haven’t used that press very much so I don’t really know if the printing surface is off due to the shimming but I got acceptable results. I also have an aluminum cast chase for my Sigwalt 6 x 9 which I bought on ebay but it doesn’t quite fit. It’s so tedious to sand it down that I haven’t ever made it functional. I would love to know a quick easy way to fix either of those chases.

Girl with a kluge
on 2 Oct 12 (06:58)

Some people have made chases out of wood. You could make one too and be printing right now.

AdLibPress
on 2 Oct 12 (08:05)

Calvert, one possible solution might be to find a blacksmith/machinist who can heat the chase uniformly to dull red and put it on a flat surface and flatten it that way, then cool it slowly to avoid adding stresses.

Bob

jhenry
on 2 Oct 12 (08:42)

If the opposite sides of the chase are parallel, you could have someone just put a spot of weld on the two high corners and then have them grind those spots down until the chase sits level. If the sides are out of square, it would be better to find a new chase as you will have problems with lockups.

Jhenry