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Lathe: when is support needed for long stock?
- Thread starter drcoelho
- Start date
- Replies 13
- Views 2,893
Scottl
Diamond
- Joined
- Nov 3, 2013
- Location
- Eastern Massachusetts, USA
I don't think there's a hard and fast rule due to differences in lathe geometry and stock characteristics but generally anytime the outboard end can flex support should be provided. You can kind of guesstimate it by trying to flex it by hand with the lathe off. If you can make it move it's highly likely that it may whip once spinning and once that happens things go bad quickly.
Larry Dickman
Titanium
- Joined
- Jan 30, 2014
- Location
- Temecula, Ca
LKeithR
Stainless
- Joined
- Sep 1, 2011
- Location
- Langley, B.C.
Nope, I think that's "too late".
I think the golden rule is: If in doubt, provide some support. In the pastif I wasn't sure I'd spin something up to 500 RPM and observe what happens. If you feel vibration at that
speed chances are good that things are gonna get ugly if you spin it up to 3500 or more...
eKretz
Diamond; Mod Squad
- Joined
- Mar 27, 2005
- Location
- Northwest Indiana, USA
Anytime the stock reaches the outboard end of the spindle as far as I'm concerned. I use bushings there and further outboard support if the stock extends much past that.
Cole2534
Diamond
- Joined
- Sep 10, 2010
- Location
- Oklahoma City, OK
Probably a stickout/diameter ratio would be best. For steel, a 1" bar sticking out 12-18" doesn't bother me at low speeds like <500 rpm. But I dont think I'd try that for plastic.
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Tyrone Shoelaces
Diamond
- Joined
- Apr 19, 2006
- Location
- Manchester, England
Err on the side of caution both in the amount of stickout and the revs you run at. I've seen it happen about 3 times in my working life. Even big bars will bend like an Allen key if provoked. You'd be amazed, it happens quicker than in that film if you have no support at all. We had all our lathes bolted down to the concrete and the last time it happened it lifted the headstock end of the lathe off the ground by about an inch by pulling 4 off 5/8" rag bolts out of the ground !
Regards Tyrone.
Regards Tyrone.
Last edited:
D Nelson
Stainless
- Joined
- Jan 7, 2015
- Location
- Missouri Ida
Over 5 times diameter should be supported
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Sent from my iPhone using Tapatalk Pro
Mike1974
Diamond
- Joined
- Nov 5, 2014
- Location
- Tampa area
I was going to say when the bar starts to bend, but I guess that is not funny or helpful. I would agree whenever in doubt, be safe and do it.
Per the video, can't believe someone would do that..
I get accidents happen, but anyone with lathe experience (I would think!) would know that bar was too long and needed support or cut in half....
eKretz
Diamond; Mod Squad
- Joined
- Mar 27, 2005
- Location
- Northwest Indiana, USA
I was going to say when the bar starts to bend, but I guess that is not funny or helpful. I would agree whenever in doubt, be safe and do it.
Per the video, can't believe someone would do that..
Dummies are dummies, no matter what they're doing.
Larry Dickman
Titanium
- Joined
- Jan 30, 2014
- Location
- Temecula, Ca
one thing that bothers me about that video, why does the camera pan over and zoom in on something that hasn't happened yet?
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
Because the guy doing the filming has some clue about what's about to happen. You can hear some running commentary (although faint), towards the end he says something like "There goes the toolbox".
Larry Dickman
Titanium
- Joined
- Jan 30, 2014
- Location
- Temecula, Ca
ah, I see it now. this video is someone filming the video on another monitor
