Taiwanese lathe spindle brake?

[Russell FurzerParticipant @russellfurzer50760]

I have a AL960B lathe – 305×960. The supplier also sells a Chinese lathe the same size that comes with a brake that works on the pulley on the lathe end of the motor drive belt. The spindle is then stopped via the geared head.

i can see some utility in such a system- more so with an electronic actuator that might be part of a system that can be activated by a limit switch- allowing threading to a shoulder etc. I can imagine a suitable control circuit.

is such a brake of value? Has anyone here made one? Would it not be better to brake the actual spindle (to avoid sudden loads via the gearbox)?

[Russell FurzerParticipant @russellfurzer50760]

[Ian S CParticipant @iansc]

I reckon that spindle breaking would be ok, as long as the lathe doesn't have a screw on spindle nose, or the chuck will do it's best to unscrew it's self. So bolt on, or cam lock OK.

Ian S C

[Russell FurzerParticipant @russellfurzer50760]

No probs with the unscrewing chuck – mines a D1-4 cam lock .

I agree that the brake on the spindle would seem the best place for it – thing is thats NOT where they seem to be fitted on similar sized machines. The usual place is the pulley on the input shaft.

My concern would be that the load would then be taken via the gearbox. Not sure if thats a problem.

Probably the reverse would happen with the brake on the spindle – the load to decelerate the (switched off) motor would be taken through the gearbox. Wonder whether a chuck has a greater inertia than the motor or vv.

Surely someones done this? My googling came up with one article from 20y ago about a pulley modified to be used as a brake in the same manner as the chinese lathes and a 1955 Pop Mechanics article in which the brake is on the motor shaft itself/

Is the whole idea a waste of time perhaps?

[LathejackParticipant @lathejack]

I have a Warco 1330 gear head lathe that has a spindle brake mounted on the headstock input shaft pulley which, as Russell says, is where they are usually fitted on these Chinese lathes.

It's a very neat installation that works very well, but it does put a strain on the headstock internals when used from high speed. I think they are really intended for emergency use only, rather than repeated use during turning.

I have only used mine twice in ten years from new, and found it was not correctly set up when delivered, so that it didn't turn off the motor power before stopping the spindle, despite being ticked off as working correctly on the lathes test flow chart. So as well as nearly cooking the motor it also nearly ripped my hands off as the spindle restarted when the brake peddle was released, ouch!!

So mine is reserved only for emergencies. Some of the geared head lathes on offer from the Far East up to 13 inch swing such as my Warco 1330, plus some of the 14 inch models, have relatively light duty headstock internals that use shafts with single keyways rather than multiple splines.

I have seen an example of a 14 inch Chinese lathe with the same headstock internals as mine that had destroyed the headstock shafts and gears from repeated use of the spindle brake with a heavy work piece in the chuck, although the operator was probably over doing it a bit. The keyways and shafts tend to twist a little due to the inertia loads, sending everything out of line, leading to self destruction. But this was a rather extreme case.

Edited By Lathejack on 30/08/2014 09:45:02

[Russell FurzerParticipant @russellfurzer50760]

Thanks for the reply.

a brake on the back of the spindle itself might be better then.

[Ian S CParticipant @iansc]

My lathe is a belt head 13 24 size Taiwanese make, I got it new in 1986, I'v never needed(haven't got) a spindle brake. I think that some lathes are braked via the motor, a DC current is switched in, that stops an induction motor.

Ian S C

Edited By Ian S C on 30/08/2014 12:30:18

[Russell FurzerParticipant @russellfurzer50760]

The issue of whether a brake would be useful is germane. I haven't 'needed' one either- haven't got one. I would like to know whether those who do have them report an advantage.

would a better design be worthwhile?

[speelwerkParticipant @speelwerk]

When I worked on the Hembrug AI, a belt driven spindle, it was normal to stop it by putting it in reverse, it worked fine and was very practical. Niko.

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