Fixing a cracked taper attachment on a Rockwell 11" lathe...

All discussion about lathes including but not limited to: South Bend, Hardinge, Logan, Monarch, Clausing and other HSM lathes, including imports

Moderators: GlennW, Harold_V

Post Reply
JoeVolcano
Posts: 14
Joined: Wed Dec 26, 2007 4:14 pm
Location: Santa Cruz

Fixing a cracked taper attachment on a Rockwell 11" lathe...

Post by JoeVolcano »

Has anyone repaired one of these? Suggestions?

Posted on Facebook as well.
IMG_0380.jpg
IMG_0381.jpg
IMG_0382.jpg
Thinking of brazing this but need to build a holding fixture for it and heat it up first...
-- JoeVolcano
pete
Posts: 2518
Joined: Tue Feb 10, 2009 6:04 am

Re: Fixing a cracked taper attachment on a Rockwell 11" lathe...

Post by pete »

Brazing is going to warp the part. That might not be enough to matter, but you won't know that until it's too late. If it does? Then your into either regrinding the part back to true or scraping it. If it were me? I think I'd machine the break square and then bolt/pin a new machined part to replicate the end features onto the OEM part. Taper attachments are desirable because it's the most accurate method of turning a taper there is. It wouldn't take much to affect the accuracy it's capable of.
JoeVolcano
Posts: 14
Joined: Wed Dec 26, 2007 4:14 pm
Location: Santa Cruz

Re: Fixing a cracked taper attachment on a Rockwell 11" lathe...

Post by JoeVolcano »

Thank you - I had thought brazing would help avoid warping (certainly as compared to true welding) I like your idea of machining a part to it.
-- JoeVolcano
pete
Posts: 2518
Joined: Tue Feb 10, 2009 6:04 am

Re: Fixing a cracked taper attachment on a Rockwell 11" lathe...

Post by pete »

IF and it's a big if you could evenly pre heat the whole part up to temperature maybe a really good hand at brazing could do it without any warpage. I still wouldn't bet on it though. In reality these taper turning slides have the same accuracy requirements as any other machine tool slide. The repair point appears to be at the end least used? But shortening up the usable length of your taper turning attachment simply because it did warp seems counter productive to me. Just remember bolts by themselves are a real poor way to insure the proper alignment between the parts. That's one reason dowels are always used on any automotive heads I know of to prealign the head to the block before the head bolts are tightened. So as I said, I'd use driven in pins just for the alignment and then a pair of bolts to do the actual work of holding the parts together. Cast iron is also fairly weak, so I'd drill/tap and use bolts that have at least 8-10 threads of engagement as well as being sure not to over torque them. Since it will be a permanent joint loctite might not be a bad idea either. Pins aren't the only way of having the parts self align, but there probably the quickest and easiest to do.
John Evans
Posts: 2366
Joined: Tue Jan 20, 2009 9:33 pm
Location: Phoenix ,AZ

Re: Fixing a cracked taper attachment on a Rockwell 11" lathe...

Post by John Evans »

Well I had a mid 20s 11" SB that had a taper attachment repaired by brazing and it worked just fine .Pre and post heating would be needed with a proper fixture. Or on the non dovetail side mill a recess and pin/bolt a piece of steel strap 1/4-3/4 x whatever width. If brazing you will need to grind back at least one side of the crack at least 1/2 way or more if one side.
www.chaski.com
Post Reply