Michael,
Thanks for the response.
The tool was set dead centre which might be part of the problem. I was
parting a 57mm diameter piece of cast iron. The overhang might have been
too much resulting in it being to low. I feel that the chatter started
as the thread was failing. I misread the situation and tightened the
usual suspects. The gibs and carriage tend to be the culprits if there
is chatter. These were tightened so that nothing would move. The only
item moving was the one axis to do the plunge cut.
I am looking for the right way of fixing IF it can be fixed at all.
Cheers,
Andrew
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On Tue, 2011-10-11 at 16:03 -0700, Michael Jablonski wrote:
Hello Andrew,
It sounds like your parting tool was set too low on the work and was
being pulled in and under the work putting excessive stress on the
tool post bolt. The parting tool needs to be set dead on center. The
chatter was probably from turning too fast. I know you didn't ask for
any advice on why this happened but thought I'd throw my two cents in.
Now you ask if it is worth repairing the compound. If you can drill
and tap the compound to accept a large bolt then I'd try to repair it.
I personally don't think that a helicoil would hold up for long but
that depends on how hard you push the lathe. It's a cheap fast attempt
at saving it.
Good luck and please let us know how it turns out.
Michael
-----Original Message-----
From: 7x12minilathe@...
[mailto:7x12minilathe@...] On Behalf Of Andrew
Sent: Tuesday, October 11, 2011 3:15 PM
To: 7x12minilathe@...
Subject: [7x12minilathe] Damaged compound
G'Day to all,
My task yesterday was to work on the cylinder for my Webster
engine. I had hogged out the fins, the lower portions and
drilled the inner diameter to 13mm. The last operation was to
part off the work from stock when I noticed a lot of chatter.
I stopped, cleaned up all the cast iron swarf and tightened
the gibs. I tied again and the chatter was just as bad. I
sharpened the tool which look OK and still no luck.
When I tried after tightening the carriage and compound do
nothing would move I tried again and the A2Z tool post (LMS
#2461) came out of the compound. The holding bolt pulled the
threads out of the compound.
When examined I noticed the bolt only penetrated a 3 or 4
turns. I knew this as the threaded part was still there like a
spring on the bolt.
At this time I need to either fix or replace the compound. I
also plan to buy or even make a suitable replacement for the
supplied bolt.
The reason for this post is to ask advice on if the compound
is worth repairing and to warn others before they have
problems.
Cheers,
Andrew in Melbourne
