9 Attachment(s)
Abused Cutterblock - Pt.1
Quote:
Originally Posted by
Vann
...The "clams" on the cutterblock are damaged as a result of the nuts being over-tightened. This has caused the base of the counterbore (where the nuts are recessed into the "clams") to dish, and the bottom to have a matching "rounding". Obviously the the forces exceeded the plastic limit of the steel.
Attachment 444206
Attachment 444207 Attachment 444205 You can see the distortion here, around the stud holes next to the "15" & "16".
The underside of each "clam" has a 1/32" recess machined the full length and most of the width (as visible in the above photos). I don't have any way of accurately measuring the "rounding" but at least one "rounding" on each "clam" exceeds this amount by at least a further 1/64".
My machinist friend has offered to machine the undersides flat, and to spot-face the nut recesses flat. This will be quite tricky as this is a skewed cutterblock - so the "clams" are thicker at one end than the other...
Yesterday we (he) set up one of the clams in his shaper and started with a 0.5mm skim.
Attachment 444213 Attachment 444212
Second pass a further 0.25mm (0.75mm total).
Attachment 444211 Attachment 444210
Third pass a further 0.25mm (1.00mm total).
Attachment 444209
At that, we had the sides flat. Time to move to the central recess with two 0.25mm passes, followed by a 0.1 pass to finish off (total recess depth 0.6mm).
Attachment 444208
Cheers, Vann.
1 Attachment(s)
Abused Cutterblock - Pt.2
This picture (0.75mm removed) really demonstrates to me how abused this cutterblock is. The distortion is so bad that the middle is higher than the edges (when it should be ~1/16" lower). The picture was taken after the second pass was completed, so it shows just how far the corners had moved.
Attachment 444214
I can only imagine it must have been overtightened to the point of distortion on one occasion. From then on the cutters can't have been held tightly over the full length, and instead of investigating the problem, they just tightened it further and further - worsening the problem. I think they were lucky there wasn't a cutter or two sent flying :C.
Strange, considering this machine spent it's entire working life at a major engineering works. Obviously at some point they had a ham-fisted person in the maintenance gang :~.
I'm not planning to use the cutterblock in the near future, but I'll keep it as I have a longer term plan... (if I live that long :no:).
Cheers, Vann.