In viewing hkcarbine's thread on his Victor top slide breaking in two as a result of a head crash it got me to thinking why lathes don't come with an adjustable limit switch that sits on the bed way! It makes sense for those questionable times with flood coolant blocking your vision or training an apprentice or a host of other issues that can arise while using power feeds.
I was thinking I might make one with the limit switch that is normally hooked up to the chuck cover. Anyone else ever do this or feel the need to?
Limit switch on a lathe
Limit switch on a lathe
Vision is not seeing things as they are, but as they will be.
Re: Limit switch on a lathe
Some of the better lathes come with dynamic stops that will disengage the power feed.
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Prepare for tomorrow!
Forgive the past!
Re: Limit switch on a lathe
My Summit 18x80 has an adjustable stop that hits a plunger in the apron which disengages the carriage feed.
Re: Limit switch on a lathe
You may end up causing the problem you are trying to avoid when you forget to set or re-set the stop switch.
My lathe also has a carriage feed kick-out that is mindboggelingly accurate, repeats to a couple a tenth, but I have maybe used it a few times in six years. I figure if I have to stand there I might as well pay attention and run the machine.
My lathe also has a carriage feed kick-out that is mindboggelingly accurate, repeats to a couple a tenth, but I have maybe used it a few times in six years. I figure if I have to stand there I might as well pay attention and run the machine.
Glenn
Operating machines is perfectly safe......until you forget how dangerous it really is!
Operating machines is perfectly safe......until you forget how dangerous it really is!
Re: Limit switch on a lathe
There is a really small BX type stainless cable sheath used with commercial sensors that would be good for this. It's only running low voltage for the contactor solenoid.
Side note: Earlier here, there were significant photos done with a strobe light timed to an operation. One could see the seperation of a chip and an exact point the OP was relating to us. Certainly this required a fast shutter speed and now we have videos. Videos are great but it isn't the exact point. One frame isn't the same as a dedicated snap of the one, especially if you don't have streaming Gbs.
Side note: Earlier here, there were significant photos done with a strobe light timed to an operation. One could see the seperation of a chip and an exact point the OP was relating to us. Certainly this required a fast shutter speed and now we have videos. Videos are great but it isn't the exact point. One frame isn't the same as a dedicated snap of the one, especially if you don't have streaming Gbs.
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Re: Limit switch on a lathe
My lathe (an old Holbrook) has power-feed trips and micrometer dead-stops, so part of my process (ritual, even!) is to set 'em up for each job to avoid running into the chuck etc. It only takes a few seconds to save the machine from MAJOR damage...
A few of the repetitive multi-cut jobs would be a hassle, but the front way cover has a gauge tray with the micrometer stop and it's simple enough to make up "job rods" or a stack of slip gauges that can be dropped into place for each cut's trip point, so I can set a cut going and wander off to get a cuppa and have a smoke - great when taking a fine (sub-thou" per rev) cut on a long part at lowish RPM
I've also got a microswitch setup using the same gauge tray and rods, that puts the VFD[1] into panic-brake-to-stop at the end of a screw-cutting pass (no threading trips or single-tooth clutch on the Model C... Yet) by disconnecting the "run forward" line - which brings the spindle to rest with the tool in a narrow run-out groove from relatively high spindle speeds; this can be really helpful when cutting metric threads on an imperial lathe when you can't release the half-nuts at the end of a cut! By just interrupting the forward line, the fwd/stop/reverse lever will still work to reverse[2] and back up for the next cut...
I can't see any reason why you couldn't put another switch (perhaps clamped to the front carriage way?) in series with the chuck or changewheel guard switches, but you *would* need to set it up for the individual job setup - rather like I have to! It would also give you a repeatable stop when cutting threads, whether imperial or metric. Combined with a tip-up threading tool holder, you can cut *any* thread surprisingly quickly without buggering about with the half-nuts and threading indicator
Depending on which lathe you have to play with, you *might* have to do a bit of head-scratching to retain reverse operation with the microswitch operated - particularly if it's Chinese/similar with a DC motor and rotary fwd/off/rev switch combined with start/stop buttons. If so... It would probably need a pair of 2-or-more-pole relays to replace the motor switching contacts in the rotary switch (with the mod' they could be used to operate the relay coils), and the microswitches in series with the relay coils?
Just my ha'pennorth,
Dave H. (the other one)
[1] If I had 3-phase, I'd have built a DC braking module for it instead... They can be fitted to single-phase AC machines, of course!
[2] A *real* nerd would, of course, fit a second microswitch behind the carriage, and automate the forward/reverse/repeat process...
A few of the repetitive multi-cut jobs would be a hassle, but the front way cover has a gauge tray with the micrometer stop and it's simple enough to make up "job rods" or a stack of slip gauges that can be dropped into place for each cut's trip point, so I can set a cut going and wander off to get a cuppa and have a smoke - great when taking a fine (sub-thou" per rev) cut on a long part at lowish RPM
I've also got a microswitch setup using the same gauge tray and rods, that puts the VFD[1] into panic-brake-to-stop at the end of a screw-cutting pass (no threading trips or single-tooth clutch on the Model C... Yet) by disconnecting the "run forward" line - which brings the spindle to rest with the tool in a narrow run-out groove from relatively high spindle speeds; this can be really helpful when cutting metric threads on an imperial lathe when you can't release the half-nuts at the end of a cut! By just interrupting the forward line, the fwd/stop/reverse lever will still work to reverse[2] and back up for the next cut...
I can't see any reason why you couldn't put another switch (perhaps clamped to the front carriage way?) in series with the chuck or changewheel guard switches, but you *would* need to set it up for the individual job setup - rather like I have to! It would also give you a repeatable stop when cutting threads, whether imperial or metric. Combined with a tip-up threading tool holder, you can cut *any* thread surprisingly quickly without buggering about with the half-nuts and threading indicator
Depending on which lathe you have to play with, you *might* have to do a bit of head-scratching to retain reverse operation with the microswitch operated - particularly if it's Chinese/similar with a DC motor and rotary fwd/off/rev switch combined with start/stop buttons. If so... It would probably need a pair of 2-or-more-pole relays to replace the motor switching contacts in the rotary switch (with the mod' they could be used to operate the relay coils), and the microswitches in series with the relay coils?
Just my ha'pennorth,
Dave H. (the other one)
[1] If I had 3-phase, I'd have built a DC braking module for it instead... They can be fitted to single-phase AC machines, of course!
[2] A *real* nerd would, of course, fit a second microswitch behind the carriage, and automate the forward/reverse/repeat process...
Rules are for the obedience of fools, and the guidance of Wise Men - Douglas Bader
Re: Limit switch on a lathe
Dave, by the sounds of you're post it's save to say you are one of those nerds you speak of .....and I got no problem with that!
Thanks for the feed back guys! As mentioned I'm not real concerned for myself but my son is at the age were he wants to learn and I'd like it to be safe despite the fact I'll be right there!
Thanks for the feed back guys! As mentioned I'm not real concerned for myself but my son is at the age were he wants to learn and I'd like it to be safe despite the fact I'll be right there!
Vision is not seeing things as they are, but as they will be.
Re: Limit switch on a lathe
This, in my opinion is a poor idea.
limit switches do fail because of operator
error, mechanical short comings in the
System, dirt, abuse etc, etc.
your son needs to learn to pay
Constant attention to the sound and
feel of the cutting operation.
In forty some years i have seen
many machines crashed because
of reliance on the limit switch.
Teach him to do it right.
use an adjustable micrometer stop,and hand
feed the last bit to the end of the cut.
Kap
limit switches do fail because of operator
error, mechanical short comings in the
System, dirt, abuse etc, etc.
your son needs to learn to pay
Constant attention to the sound and
feel of the cutting operation.
In forty some years i have seen
many machines crashed because
of reliance on the limit switch.
Teach him to do it right.
use an adjustable micrometer stop,and hand
feed the last bit to the end of the cut.
Kap
Fadal Turn, Fadal Vmc 15, Prototrak 16 x 30 Cnc Lathe, Pratt and Whitney 16 x 54 lathe, Pratt and Whitney Vertical Shaper, G & E 16" Shaper, B & O Electric turret lathe, 36" Doall band saw,
Enco B.P. Clone, Bridgeport CNC Mill, Delta 12" Surface Grinder.
Enco B.P. Clone, Bridgeport CNC Mill, Delta 12" Surface Grinder.
Re: Limit switch on a lathe
Good advice Kap, Thanks......
Vision is not seeing things as they are, but as they will be.