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chair spindle

Posted: Thu Mar 11, 2010 9:08 am
by garyspens
I'm not totally new to the lathe but I am new to turning long pieces on the lathe. I'm trying to turn a spindle for a chair. It's 28" long. When I get toward the middle of the piece I start getting chatter. The diameter right now is about 1" and I have to go down to a tad smaller than 5/8". Is there a good chance of this piece breaking before I get finished? Should I have a center rest for this piece?
My first one and if this is successful I have another one to do. I'm turning oak.
Thanks,
garyspens

Posted: Thu Mar 11, 2010 9:47 am
by JPG
Are you cutting, or scraping?

chair spindle

Posted: Thu Mar 11, 2010 10:13 am
by garyspens
Okay, so I'm newer than I thought. Don't know the difference between cutting or scraping.

Posted: Thu Mar 11, 2010 10:26 am
by JPG
The chattering will be much worse if you are 'scraping'.

Scraping is when the material is being removed by the tool edge being pressed against the workpiece at a near right angle to the axis of rotation of the workpiece. That is, if the tool could be pressed all the way to the center of the workpiece, the tool edge would meet the center of rotation.

Cutting is a technique where the the tool edge is raised above the scraping position on the workpiece and positioned so that the cutting is directed across the workpiece(towards either end). The material is 'peeled' off sideways rather than from the surface of the workpiece directly in front of the tool.

I leave if for others far more experienced than I to elaborate/direct you to additional info.

chair spindle

Posted: Thu Mar 11, 2010 10:49 am
by garyspens
I'm using a gouge so far for roughing, so maybe I'm doing a little of both?
garyspens

Posted: Thu Mar 11, 2010 10:54 am
by JPG
Does it still chatter after getting it down to round? Are you 'forcing' it(trying to cut too fast, with too much pressure)?

Is your gouge sharp?

What does the grain look like?

Posted: Thu Mar 11, 2010 11:34 am
by garyspens
The gouge is sharp. I didn't notice the chatter until I got it round. Probably too much beating, taking the corners off. If I take a very light cut I get no chatter, but I can't imagine how long it will take to do this project with the light cuts.
I actually have a steady rest on order from Shopsmith but it's backordered and I have the piece on the lathe now.
The grain just looks like oak grain but a little rougher than I would have thought.
Does it help to turn the piece end for end?

Posted: Thu Mar 11, 2010 11:50 am
by pennview
It's possible that you're experiencing some whipping action of the stock. If that's the case, the steady rest should cure the problem. If you have an older copy of Power Tool Woodworking for Everyone, in the Lathe section, it shows how to build a steady rest or what they call a "backrest."

Posted: Thu Mar 11, 2010 11:59 am
by garyspens
I may have that book if it's one you get with the Shopsmith. Never thought of looking there. You don't get a lot of 'whipping' action making a pen, so this caught me by surprise. I guess it shouldn't have but it did. Such is life! Thanks, guys. If I can make something like a backrest that will fix me for now.
garyspens

Posted: Thu Mar 11, 2010 12:42 pm
by joedw00
Welcome to the forum garyspens. I just checked out your profile, I bet most of us would believe what your occupation is. There are all kinds here. :D