in between center turning help

Signed-In Members Don't See This Ad
jbeyer

jbeyer

Member
Joined
Mar 31, 2010
Messages
42
Location
Maryland
I tried today to turn a piece of tru-stone in between centers. The problem that I had was that I wanted to round the blank to fit into my 3/4" collet so I put it between a steb center and a live center. The problem was that when I placed ant kind of pressure on the quill the blank chipped. Does anyone else have this problem?

Jonathan
 
Signed-In Members Don't See This Ad
A couple of suggestions did you centre drill the ends first to sit into the centres ? . And it does help a lot if you take as much of the corners off the blanks as practicable toy reduce the amount you need to turn . The truestones have varying degrees of hardness ,and hitting the corners with a chisel is really setting up a hammer effect on the centres . Depending on the pen you are attempting it may pay to find a suitable sized guide bush and drill the ends out just enough for the guides to fit as neat as you can ,this will spread the loading much better on the blank , you can always redrill for your tubes once you have it sized for your collet :) good luck with it ,sharp tools and not too much speed as it will act as a grindstone on your chisels .
 
Thanks guys... the problem is that I still had the same problem today even when I didn't use tru stone... I used amboyna burl. I think it is from too much pressure that I place on it through the quill. The only reason that I have to put that much pressure is so that the spikes on the steb will go into the wood. Would taking a mallet and hitting it into the steb work? Or is there something that I'm missing here.

Jonathan
 
jbeyer said:
Thanks guys... the problem is that I still had the same problem today even when I didn't use tru stone... I used amboyna burl. I think it is from too much pressure that I place on it through the quill. The only reason that I have to put that much pressure is so that the spikes on the steb will go into the wood. Would taking a mallet and hitting it into the steb work? Or is there something that I'm missing here.

Jonathan
Click to expand...

Are you using a Sorby type steb center, or the one that came with your lathe? The one that came with your lathe likely has four blades and these are quite nasty on some materials.
I use this PSI multi tooth unit, and have pretty good luck not chipping blanks:
http://www.pennstateind.com/store/LCENTSS21.html
You may need to drill the little hole as some have suggested, that can help keep the point from splitting in.
Also, as you start, apply moderate pressure with the tailstock, and as you turn, retighten the tailstock occasionally. The centers will sink in at their own rate a bit easier. Pounding with a hammer does not sound good.:biggrin:
The spikes or blades seem to sink in easier if the lathe is running and you turn some on the blank a bit, for me anyway. Just retighten as needed.
Ease it in, don't muscle too much and I think your problems will fade.
 
I have that PSI one Jojnnycnc is talking about, got it about a month ago. It is worth getting, I will be ordering some bigger ones also. Not sure how it works on trustone, haven't tried it yet but works great on wood. I put a little indent in the center is the wood with a awl (each end) before I start.
 
I use a dead center to drive the blank . I center mark the blank end and use a pick or center punch to make a dimple . Then I let the dead center spin and deepen the dimple until it is deep enough to hold the blank (normally about 1/8" to 3/16" deep) . Then I tighten the tail stock enough to drive the blank and turn down the blank to 3/4" round .
There are several advantages to doing it this way . First , I don't have to worry about hitting the drive rim or blades with my turning tools . Second , if I get a catch the blank will stop spinning instead of chipping or self destructing . Third , I now have a perfectly centered dimple that centers the drill bit for drilling on the lathe . I find this is the most efficient way for me .
It takes a little practice but the advantages are worth the extra effort to learn .
 
You must log in or register to reply here.
Back
Top Bottom