broke my tool rest on my mini
#11
  
Does cast iron weaken and get brittle over time. Had the outside of a bowl nearly finished. Stopped the lathe looking it over. I had a few tool marks. Started it up and just touched the bowl with the gouge and it snapped the crossarm off the vertical shaft. Didn't look like it was cracked and rusty and break. 

Trying to decide what to get for a replacement. Any suggestions. 5/8 shaft by  the way.
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#12
  Re: broke my tool rest on my mini by gear jammer (Does cast iron weake...)
(06-05-2020, 11:06 PM)gear jammer Wrote: Does cast iron weaken and get brittle over time. Had the outside of a bowl nearly finished. Stopped the lathe looking it over. I had a few tool marks. Started it up and just touched the bowl with the gouge and it snapped the crossarm off the vertical shaft. Didn't look like it was cracked and rusty and break. 

Trying to decide what to get for a replacement. Any suggestions. 5/8 shaft by  the way.

I think that Robust makes the best tool rests.
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#13
  Re: broke my tool rest on my mini by gear jammer (Does cast iron weake...)
(06-05-2020, 11:06 PM)gear jammer Wrote: Does cast iron weaken and get brittle over time. Had the outside of a bowl nearly finished. Stopped the lathe looking it over. I had a few tool marks. Started it up and just touched the bowl with the gouge and it snapped the crossarm off the vertical shaft. Didn't look like it was cracked and rusty and break. 

Trying to decide what to get for a replacement. Any suggestions. 5/8 shaft by  the way.

Sixty bucks more or less from these folks.  Select your length, and in the future, rest close, hold tool firm to the rest as you swing to start, and cut downhill.  https://www.thewoodturningstore.com/
Better to follow the leader than the pack. Less to step in.
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#14
  Re: broke my tool rest on my mini by gear jammer (Does cast iron weake...)
I get my tool rests here

https://www.pennstateind.com/mm5/merchan...tool+rests
It is always the right time, to do the right thing.

Hi, I'm Arlin's proud wife! His brain trma & meds-give memory probs and has pain from injuries, but all is well materially & financially.  
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#15
  Re: broke my tool rest on my mini by gear jammer (Does cast iron weake...)
Broke one (cast) on my 60's era sears lathe and I ground the break to a V and used A spring steel rod and welded it back. Finished the weld down smooth and it's still good.
Steve





 
The Revos apparently are designed to clamp railroad ties and pull together horrifically prepared joints
WaterlooMark 02/9/2020

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#16
  Re: broke my tool rest on my mini by gear jammer (Does cast iron weake...)
An opportunity to pick up a longer rest: I got mine at Rockler:

Rockler Tool Rests
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#17
  Re: RE: broke my tool rest on my mini by Philip1231 (An opportunity to pi...)
(06-06-2020, 04:43 PM)Philip1231 Wrote: An opportunity to pick up a longer rest: I got mine at Rockler:

Rockler Tool Rests

One thing to watch is the length of the post.  A little short may not be a problem, but too long could be.  It can move the horizontal surface sufficiently high to position it well above centerline.  I bought a S bowl tool rest with a threaded post and ran into this issue.  I ended up having to cut about 1/2" off the post to get the centerline down where I needed it.  This was much easier as the rest portion could be unscrewed from the post so it could be fit into a metal lathe to cut it off.
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#18
  Re: RE: broke my tool rest on my mini by badwhiskey ([quote='gear jammer'...)
(06-06-2020, 08:19 AM)badwhiskey Wrote: I think that Robust makes the best tool rests.

+1 on the Robust rests. They are definitely my favorite.

I would love to see a good close-up picture of the break. It is surprising that there was no sign of rust or discoloring on the fracture surface.
"the most important safety feature on any tool is the one between your ears." - Ken Vick

A wish for you all:  May you keep buying green bananas.
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#19
  Re: broke my tool rest on my mini by gear jammer (Does cast iron weake...)
I'm strongly leaning toward the Robust or staying with the original manufacture (Grizzly). I'll decide and order one tonight so it can ship tomorrow. I had a welding shop look at the old one and he said he could weld it but would not guarantee to levelness to  the lathe bed. Would be close but would not claim perfect fit. I told him to weld it gives me a spare. 
I do run my tool rest close to my work. I hate the chatter you can get if to far away. My arthritis in my hand and elbow hates the unneeded vibration.
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#20
  Re: broke my tool rest on my mini by gear jammer (Does cast iron weake...)
(06-05-2020, 11:06 PM)gear jammer Wrote: Does cast iron weaken and get brittle over time. Had the outside of a bowl nearly finished. Stopped the lathe looking it over. I had a few tool marks. Started it up and just touched the bowl with the gouge and it snapped the crossarm off the vertical shaft. Didn't look like it was cracked and rusty and break. 

Trying to decide what to get for a replacement. Any suggestions. 5/8 shaft by  the way.

Cast iron has a tendency to have stresses built up in the casting.  Best practice for foundries is to perform a stress relieving heat treat.  It not performed, the retained stresses can lead to cracking.  How long those stresses are retained has a lot to do with the thickness of the casting, location of retained stresses, and geometry of the casting.
Still Learning,

Allan Hill
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