# Lathe carriage stop



## Charles scozzari (Mar 25, 2022)

Hello,This carriage stop is mounted underneath and rides with the carriage. The first photo shows the cover over the threads to keep it clean. With the cover removed I can run the 5/8 11 rod out up to 14" and lock, I rather this to a clamp on for the bed rail.  It should not be used with the feed, But if I do I stop the feed on the run and finish up feeding manually. It is a solid stop that will not move when I'm finishing off a run of 60 custom lenth rods or any other work. Thanks for looking.


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## cathead (Mar 25, 2022)

It's a good and *SOLID *_stop.  _It's better than stops mounted on the front way. I like it!


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## Charles scozzari (Mar 25, 2022)

cathead said:


> It's a good and *SOLID *_stop.  _It's better than stops mounted on the front way. I like it!


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## Uglydog (Mar 25, 2022)

That is a great idea!!
Yes, don't ever use it with a power feed... or at least be very attentive and disengage the pf on approach to the stop.
Could be used on both sides in the event one is turning a shaft with a profile on both ends. 

Great idea!!

Thank you,
Daryl
MN


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## Charles scozzari (Mar 25, 2022)

cathead said:


> It's a good and *SOLID *_stop.  _It's better than stops mounted on the front way. I like it!


Thanks for the LIKE, I really thought I might have opened a can of worms.


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## Charles scozzari (Mar 25, 2022)

cathead said:


> It's a good and *SOLID *_stop.  _It's better than stops mounted on the front way. I like it!


Thanks very much.


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## woodchucker (Mar 25, 2022)

Charles scozzari said:


> Thanks for the LIKE, I really thought I might have opened a can of worms.


hell no. There's always more than one way to do things. It's not wrong, it's different.  For me it wouldn't work. my SB9 is open under the head. I had to put a piece of sheet metal there to keep from losing stuff in the bed foot.. But it's a great way to do it.


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## Charles scozzari (Mar 25, 2022)

woodchucker said:


> hell no. There's always more than one way to do things. It's not wrong, it's different.  For me it wouldn't work. my SB9 is open under the head. I had to put a piece of sheet metal there to keep from losing stuff in the bed foot.. But it's a great way to do it.


Thanks so much, I appreciate your kind reply.


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## extropic (Mar 25, 2022)

@Charles scozzari 

Please elaborate on the intention of the smaller (1/4"?) diameter portion of the stop rod and particularly the groove (1/8" ID?)

I like the idea. I'm away now, but when I get home I intend to see if your concept is easy to implement on my lathe's configuration.


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## Charles scozzari (Mar 25, 2022)

Hi, I am working on a devise that along with the bulb in question would snap the bulb and trigger the emergency stop circuit through a micro switch before crashing the carriage into the chuck. Without the bulb as part of the stop circuit setting a micro switch to trigger the stop would remove the solid stop design. At present I am using it as it is. I may abandon the idea and cut the bulb off since it works well as is, and I still would have the shear pin as a safety. Thanks and hope this helps explain the intended use of the bulb.      Charlie


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## Charles scozzari (Mar 25, 2022)

extropic said:


> @Charles scozzari
> 
> Please elaborate on the intention of the smaller (1/4"?) diameter portion of the stop rod and particularly the groove (1/8" ID?)
> 
> I like the idea. I'm away now, but when I get home I intend to see if your concept is easy to implement on my lathe's configuration.


I believe this can be made to work on any lathe large or small including lathe heads mounted on top of the bed by having a stop mounted between the ways.  Thanks for your interest and question.


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## Charles scozzari (Mar 25, 2022)

Thanks, I really appreciate that.


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## graham-xrf (Mar 25, 2022)

I did try to dream up  a two-stage limit switch, interlocked with the power feed.  A stop within a spring loaded tube, and a switch sensing the feed lever, or mechanism. The idea is that if you are manually feeding, you can go all the way to the solid stop.

If, by some chance, you forget, and have the power feed on, you have effectively "armed" the first level limit switch to bring the lathe to a halt when it finds the spring-loaded limit switch on the stop. Lathe coming to a halt is assisted by motor dynamic braking into a resistor load. A swift stop, but not violent, yet rapid enough that the spring loading is not completely taken up.

It was a pipe dream scheme. So far, I have not messed up, but I keep refining it in my mind.


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## Charles scozzari (Mar 25, 2022)

graham-xrf said:


> I did try to dream up  a two-stage limit switch, interlocked with the power feed.  A stop within a spring loaded tube, and a switch sensing the feed lever, or mechanism. The idea is that if you are manually feeding, you can go all the way to the solid stop.
> 
> If, by some chance, you forget, and have the power feed on, you have effectively "armed" the first level limit switch to bring the lathe to a halt when it finds the spring-loaded limit switch on the stop. Lathe coming to a halt is assisted by motor dynamic braking into a resistor load. A swift stop, but not violent, yet rapid enough that the spring loading is not completely taken up.
> 
> It was a pipe dream scheme. So far, I have not messed up, but I keep refining it in my mind.


Hello, WOW I was going with using a normally closed micro mounted at the 5/8" threaded rod and extending onto the what I am referring to as the bulb If I am understanding your approach the spring will void the solid stop feature.        I thank you for your interest and idea. It is food for thought.


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## extropic (Mar 25, 2022)

@Charles scozzari

I'll try again.

Please elaborate on the intention of the smaller (1/4"?) diameter portion of the stop rod and particularly the groove (1/8" ID?)


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## Charles scozzari (Mar 25, 2022)

extropic said:


> @Charles scozzari
> 
> I'll try again.
> 
> Please elaborate on the intention of the smaller (1/4"?) diameter portion of the stop rod and particularly the groove (1/8" ID?)


Hello, please refer to post #10 for an in-depth explanation of my intentions.   Thanks.


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## extropic (Mar 25, 2022)

Charles scozzari said:


> Hi, I am working on a devise that along with the *bulb* in question would snap the bulb and trigger the emergency stop circuit through a micro switch before crashing the carriage into the chuck. Without the *bulb* as part of the stop circuit setting a micro switch to trigger the stop would remove the solid stop design. At present I am using it as it is. I may abandon the idea and cut the bulb off since it works well as is, and I still would have the shear pin as a safety. Thanks and hope this helps explain the intended use of the *bulb*.      Charlie



Bulb? I don't see anything in the picture that I recognize as a bulb. Since you didn't address the reply to me, I didn't recognize it as trying to answer my question.

I interpret your intent to be that the features I asked about are for a potential design option.


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## graham-xrf (Mar 25, 2022)

Charles scozzari said:


> Hello, WOW I was going with using a normally closed micro mounted at the 5/8" threaded rod and extending onto the what I am referring to as the bulb If I am understanding your approach the spring will void the solid stop feature.        I thank you for your interest and idea. It is food for thought.


Hi Charles
I thought one needed some sort of reliable thing to signal when the power feed lever is in ON position, which provides the first half of the logic.

The next thing that needs to be sensed is when the carriage really must not be going any closer (under power). Something that will take it out of trouble before it hits the solid stop. The closed limit switch riding on the carriage stop provides that, and it will move, along with the stop, to wherever you set it.

Mechanically, it could be a coaxial tube, or a separate rod or whatever, but the key thing is that it operates a bit before the carriage hits the stop, while not actually stopping anything if the carriage is being moved safely by hand.

Let us ignore complicated stuff like using an actuator to yank the feed lever out of engagement. The simpler, cheaper, way, that gets your attention, is to just wire the two switches in series with the lathe E-Stop. Spring load a rod if you like, but you don't have to. You can avoid crushing the limit switch by using one of the many switch shapes with lever bumps that can operate the switch as it "passes by".

Dynamic braking is a refinement if the lathe keeps coasting on to a long halt from inertias. If the limit has a sufficient gap to the hard stop, it will work anyway.




OK - it's a quick 'n dirty scribble that may not yet be mutt's nuts, but the idea is that if the power feed is in a "safe" position, i.e. not engaged, the anti-crash limit switch is bypassed via the NO (normally open) contact on the power feed sensing switch. If the power feed is engaged, it will have to obey the anti-crash limit switch, which can be set with some gap before the hard stop. If you ride into it with the power feed lever ON, the lathe will stop _before_ it rides into the hard stop.

I am sure that folk here can come up with refinements, and all manner of various tidy mechanical arrangements that will do this, but it's a start.


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## woodchucker (Mar 25, 2022)

graham-xrf said:


> Hi Charles
> I thought one needed some sort of reliable thing to signal when the power feed lever is in ON position, which provides the first half of the logic.
> 
> The next thing that needs to be sensed is when the carriage really must not be going any closer (under power). Something that will take it out of trouble before it hits the solid stop. The closed limit switch riding on the carriage stop provides that, and it will move, along with the stop, to wherever you set it.
> ...


you can also use reed switches. They come in both normally open and normally closed. but they require a magnet (oh that doesn't work with metal like it does with wood)...


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## graham-xrf (Mar 25, 2022)

woodchucker said:


> you can also use reed switches. They come in both normally open and normally closed. but they require a magnet (oh that doesn't work with metal like it does with wood)...


A reed switch would work, even if there is some aluminium between it and the magnet, and they are way more reliable than micro-switches. A little magnet on the end of a rod could work.
BUT
One likes something enclosed, and not gathering a huge pile of magnetic chips and crud, The thinking needs to be for simple, elegant, robust, cleanable, reliable.


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## Charles scozzari (Mar 25, 2022)

graham-xrf said:


> Hi Charles
> I thought one needed some sort of reliable thing to signal when the power feed lever is in ON position, which provides the first half of the logic.
> 
> The next thing that needs to be sensed is when the carriage really must not be going any closer (under power). Something that will take it out of trouble before it hits the solid stop. The closed limit switch riding on the carriage stop provides that, and it will move, along with the stop, to wherever you set it.
> ...


Hi, Thanks for the viable option along with the schematic. It actually would work very well in my set up. Thank you for your time and help.


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## Charles scozzari (Mar 25, 2022)

I agree. Having worked in the elevator industry I just happen to have both the reed and micro switches laying around. I want to make sure not to have to big a switch in the rather tight area. I will post what I end up doing.   Thanks again.


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