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ZINOM
03-23-2005, 11:02 PM
I'm having a little trouble with my 12' Craftsman lathe.

First off, it has a ton of trouble if I try to part stuff off....I have the need to part off 3/8" 1002 rod, and I have no problem doing it on my Smithy 1220 (it was a three in one but the mill head's been removed)....but the Craftsman shimmys like a bugger and then the motor cuts out.

I position the switch to "off" and try again....when it seems like the load is increasing it shuts off again......?

I didn't think I was asking very much from this machine, considering the cheap chinese machine has no trouble with the task.

Any advice?....Motor? switch?.....it's a reversable motor, would I be able to swap it out for a single directional motor if it's the culprit?

Thanks all,

John

darryl
03-23-2005, 11:35 PM
Sounds like maybe the vibrations are affecting the switch, or maybe the temperature cutout, or overload device. Why is there so much vibration- I would look there first before blaming the motor. You know, all the usual- cutter height, various loosenesses, etc.

captainkirk
03-24-2005, 07:12 AM
What size motor are you using? Maybe its not "so much" the lathe (although you likely need to tighten the gibs) if the motor is way to small your going to have these type of "issues"
I wouldn't have less than a good one HP motor on a 12" lathe. get a motor with some mass to it, not a fan motor but one rated for loads like your doing. Older motrs have more mass and therefor are likely to have better "Flywheel effect" this storage of power in the mass of a rotating object helps to smooth out the load and give better results.

Having said that "parting off is the one operation that is likely going to task the machine and the newer operator the most, do some reading on feeds, speeds and lubes.

Good luck

wierdscience
03-24-2005, 07:45 AM
How wide is the parting tool?On the smaller lathes I never use more than a 3/32 or 1/8".

The motor stall could be due to a motor bearing trying to seize or one that is running dry if it's a sleeve bearing motor.Just a thought.

BillB
03-25-2005, 01:28 AM
I don't have any particular trouble parting 3/8" tool steel on my SBL 10K with a 1/2 HP newer motor, although I think Kirk is right that bigger and older are to be preferred. Are you using cutting oil? I slather parting cuts with plenty of Mobil Gamma (sulfur oil, aka machinist perfume).

BillB

C9
03-25-2005, 08:50 AM
I'm curious if you guys are parting off solid stock or if it's been drilled/bored?

I lost one MT2 arbor I was making when I tried to part it off.

Since then I don't part off solid stock.

(My lathe is a 12 x 36" Atlas/Craftsman with 1 HP motor and it parts off just fine with a 1/8" cut off bit. Too boot, it had greasy belts and still worked ok. Did replace the belts and clean the lathe up a while back.)