Lathe problem

[gobbypunk]

Hi guys why would this chunk shake the lathe around like mad your thoughts as always are appreciated

Thanks Mark

[TheHungrySquirrel]

To fast a speed, piece off centre slightly.

[se7enthdevil]

sounds unbalanced to me.

 

 

start at as low a speed as the lathe will allow and gently rough down to a cylinder.

[gobbypunk]

Thanks guys will have a look tomorrow 

[Stubby]

Get a pen . Turn the piece by hand whilst holding the pen against the face . Take it out of the centers and band saw the worst off to out side the line . Put it back between the centers and start on a lowish speed taking fine cuts until it comes into balance .

[ABtrees]

Hi Mark

 

Hope you're recovering well

 

Try one of these. 

 

https://www.axminster.co.uk/axminster-centre-finder-340146

 

I have one - it's cheap and tacky but really useful in removing some of those wobbly issues  !!

 

 

[se7enthdevil]

the center of the bit being turned is not always the center of gravity in the block.

[Vespasian]

One of my customers gave me one of those laths a year or so back..  all I've done to date is piss about with a bit of old wood and attempt to get it round..  used it for ten minutes max..

 

Now if someone would post a pic of any work done on it it might inspire me to have another dabble on it..

[ABtrees]

55 minutes ago, se7enthdevil said:

the center of the bit being turned is not always the center of gravity in the block.

I agree Steve - that's why I wrote 'some'.

 

You are way, way more experienced at this stuff than me so how on earth does one compensate for an off centre C of G once it's roughed into a cylinder ?  I genuinely haven't a clue - anything like that goes back into the log basket !

[se7enthdevil]

there are a few things you can do.

 

1.

bolt the lathe down and add lots of heavy bags of sand or weigh it down as much as possible.

 

2.

buy a nice big heavy lathe that is all thick cast iron all over and in the region of 350kg plus.

 

3.

reposition the work so it's as centered as possible on its C of G but this is not always possible.

 

4.

turn at a very low speed.

 

5.

use another bit of wood.

 

 

 

finding the center of gravity is easy once it's round. let it roll on a flat level surface and when it stops rolling around strike a line vertically on both ends and this will give you the correct plane to find your center on once it's back on the lathe.