Denford Software & Machines

i'm getting chatter on the microturn when i am turning a mini baseball bat 2.6 inches long designed on lathcam designer. i'm not sure if i am doing something wrong or if that is simply too long and thin to be stable in a chuck.
any suggestions? i tried slowing the feed rate to 40% and that was no help.

What material is it ?
Are you able to hold it on the tailstock ?
Have you got a new sharp tool and is the centre height set correctly ?

i am turning 1/2" aluminium. i've designed the piece on lathecam designer and used the default g code settings: feed rate 5.512, roughing and finishing cut 0.0197.

i would need to redesign to use the tailstock, and i also have not found a tailstock clamp or center or whatever should be used for this machine/material so for now that isn't possible.

the tool is most definitely not new, but it seems sharp.

not sure how to set the center height, but i set up the offsets correctly. when i jog the machine to x=0, it seems to be at the middle with the old 'carpenter's eye' test.

also, i have machined the test part that is included with the software and it turned out fine (no chatter). that part is 3/4" and a lot shorter than the one i am having problems with.

Hi,

No matter what you do with a long part once you reduce the diameter the bar will flex and this can cause chatter.

Designing somthing like a baseball bat should be done in 2 operations. If you keep the thicker end of the bar towards the chuck this will help. so machine the handle end of the bat furthest away from the chuck.

You could also check the machine slides are tight. If you grab the slide and see if you have side to side movement. If so tighten the Gib strips.

Refer to the attached site for mechanical adjustment of the machine.

http://www.sherline.com/setupins.htm