# Automatic Feed Stop



## Billh50 (Jan 28, 2015)

This is my idea for an automatic stop for a mini-lathe. I do have more to do to it.

http://i1321.photobucket.com/albums/u560/bhalsdorf/AutomaticFeedStop.jpg


----------



## RVJimD (Jan 28, 2015)

Bill,

is the black part the carriage hand wheel?  It looks backwards from my grizzly, or  maybe I'm looking at the back side of your drawing.

i would love to do this sort of mod to my lathe.  Show us more as you move forward with the mod!

jim


----------



## Billh50 (Jan 28, 2015)

Yes that is the hand wheel to move the carriage manually.

I got this idea from someone who posted something similar for disengaging the threading nuts. I just wanted to make it like a simple add on. Once I get it all planned out I will be adding it to my mini-lathe. Since the threading nut is also used to feed I can use this for stopping a thread at a shoulder as well as a feed up to a shoulder.


----------



## Billh50 (Jan 30, 2015)

Just finished the first part. The Engagement Lever.


----------



## Billh50 (Jan 31, 2015)

Today I did some hunting for stock and things needed to finish the Stop. I found just about all I am going to need except I was thinking of changing the Pins in the actuator rod to just clamp collars. I only had one so will have to buy some. I knew I should have stocked up on stuff before I left my last job.
Anyway....being such a short list that I need to buy I am trying to think of other things I need to order while I am at it to cover shipping charges.

Guess I'll spend the evening thumbing through the McMaster catalog.


----------



## rwm (Jan 31, 2015)

I like this idea. 
I am also thinking about doing this with a micro switch and a solenoid. I feel like that may be more repeatable. Thoughts?
R


----------



## Billh50 (Jan 31, 2015)

well this is for my mini-lathe which uses the same feed lever for both cutting and threading. So this will work great for doing either up to a shoulder. It will stop the saddle in the same spot every time.


----------



## Billh50 (Feb 2, 2015)

Today I made the mounting bracket.


----------



## Billh50 (Feb 3, 2015)

Decided to remove the cross feed plate today. That way it will be easier to locate all mounting holes. Of course while I was at it I thought maybe I should make an extension for the hand wheel to get it out a bit further. (always something to improve) While taking a short break I decided to put in my order to McMaster Carr since I found a could things I could use. Will post a photo once I have everything mocked up and ready to mount.


----------



## Billh50 (Feb 7, 2015)

Got the apron on and all the parts that go on it today. Will post a photo later. Tomorrow will be working on the adjustable stop for it. With lathe running I can shut off feed by pushing on the actuator rod. So it should work perfect.


----------



## Billh50 (Feb 7, 2015)

Well it looks like it will have to wait until wednesday before I can get to the adjustable stop. Have to order a small piece of stock. So it will be Tuesday afternoon before I can get the stock.


----------



## Billh50 (Feb 8, 2015)

Update on progress.


Just did a quick trial with a jury rigged solid stop. The shut off works fine for normal feed rates and fine pitched threading. But as the threading gets somewhat coarse the spring that returns the handle to the neutral position does not have enough strength to disengage the split nuts. Evidently the pressures against the split nut is greater as the pitch increases. I am going to try a torsion spring instead as I can get more spring pressure that way. Once I get everything working good I will have update plans available. This may come in handy for those with mini-lathes and other may be able to alter the plans to suit.


----------



## great white (Feb 8, 2015)

Very interesting, you've got my brain turning on a design of my own now. 

I would like to build an automatic stop just to prevent "newbie" crashes into the chuck if nothing else.....


----------



## Billh50 (Feb 8, 2015)

that was why I started this. I came close a couple times to hitting a shoulder. I know it will work for me once I get the right spring tension because it works great at slow feeds. And once it's done I should be able to repeat the stop position every time.


----------



## Billh50 (Feb 8, 2015)

Here's a photo.


----------



## rwm (Feb 10, 2015)

Looking good. I am curious to see how the repeat-ability is. I would think any slop in the system could cause problems. Please follow up with us after testing it out.
Your latch reminds me of an AR trigger!
R


----------



## Billh50 (Feb 10, 2015)

The spring will be in today. Once I get it to release good I am going to set up an indicator to check repeatablity.


----------



## juiceclone (Feb 10, 2015)

Having worked in a production shop on Porter-Cable lathes many years ago, I very well remember that the mechanical feed stops supplied with the lathes from the factory did have issues with repeatability.  The heavier the cut, and even the duller the tool became in production, the more stress on the feed engagement gear/dog? and the further it would hang on till disengaging.  We had to have the same depth cut on each pass to ensure there were no disasters!!   I have a homemade stop on the halfnut lever on my Chinese lathe but I don't really trust it. If I was to build an auto feed stop for the feed lever, I would use a micro switch and a solenoid to disengage.  We had used a similar system on some Logan lathes, and the disengage point was very stable, an air cylinder was used not a solenoid, but the stop point was very reliable
:makingdecision:


----------



## rwm (Feb 10, 2015)

juiceclone said:


> Having worked in a production shop on Porter-Cable lathes many years ago, I very well remember that the mechanical feed stops supplied with the lathes from the factory did have issues with repeatability.  The heavier the cut, and even the duller the tool became in production, the more stress on the feed engagement gear/dog? and the further it would hang on till disengaging.  We had to have the same depth cut on each pass to ensure there were no disasters!!   I have a homemade stop on the halfnut lever on my Chinese lathe but I don't really trust it. If I was to build an auto feed stop for the feed lever, I would use a micro switch and a solenoid to disengage.  We had used a similar system on some Logan lathes, and the disengage point was very stable, an air cylinder was used not a solenoid, but the stop point was very reliable
> :makingdecision:



So would you use a 120v control circuit with a heavy duty microswitch? You could use a lower voltage control circuit and a Triac or something similar. Can any of you electrical gurus suggest a schematic?
R


----------



## juiceclone (Feb 10, 2015)

On the old systems it was straight 110 vac.  The micro sw used was a "* BZE6-2RN*"  15 amp ac, 500 ma dc.   If I were doing it, I'd prob go with DC and have a capacitor discharge thru the solenoid leaving a small current running as long as the sw was still actuated.  Shouldn't be too much to it. 
That particular microsw in it's housing  is expensive new, but can be had used and when you take it apart there is a conventional microsw inside that can be replaced with a new one.  
Guess I've been thinking about this in my sleep for a while    :>))
:nervous:


----------



## Billh50 (Feb 15, 2015)

sorry I haven't posted anything here lately. Health issues have prevented me from getting down into the shop lately. Will get back to it soon though.


----------



## Billh50 (Feb 17, 2015)

Just an Update:

Well I got down into the shop yesterday. After relieving the end of the catch knob for the torsion spring, I found I had to remove 1 coil off the spring so it would fit. I did that and made a quick fixture to hold the spring for bending the legs. They may not look great but they work. The saddle can now be under stress and the spring still releases the half nuts. I am now looking for a piece for my next project that needs threading to try it out.


----------



## Billh50 (Feb 19, 2015)

Well here are some prints to look at. If I missed anything please let me know.


----------

