PM940V and the BS-2 Universal Dividing Head, Thoughts welcome....

[verbotenwhisky]

So, I have a PM940V-PDF Mill and I am planning on buying the BS-2 Universal Dividing Head which when setup to cut a helix or worm gear will be driven by the tables x-axis lead screw through a geared connection on the left end of the table. Has anyone else here attempted to couple these 2 pieces of equipment? What is the issue you ask? well let me explain.....

My mill is a large bed mill as most who have this machine will know and unlike a knee mill its X-axis power feed is mounted to the left side of the table, the power feed actually hangs off parallel to the table top, over the lead screw en making it inaccessible which is where the dividing head drive gears should mount when it is in use. Well VW, "why not just connect the BS-2 to the right hand side of the table" you ask? Well if I did that it would rotate the opposite direction and the handle and dividing plates would be on the back side of it (away from operator). Okay you say, "Mount the X-axis feed on the right hand side of the table" well.... same issues....

OKAY.... with all of that said here are some of the solutions I see (I am looking for input here) A) I can buy a knee mill x-axis feed which would mount on the right side of the table, this would require custom fabricated brackets which would not be a problem but I am not certain the rest of it would work, anyone else done this? B) I can study making a custom bracket for the current X-axis feed, not certain I see this because the thing hangs on the lip of the table and covers it up. C) remove the feed and operate manually when using the BS-2, I really want the feed.

Anyone think of an option I have missed? Ideas?

My Mill as is currently:

BS-2 Universal Dividing Head:

This is is one connected to a mill (Came from Stock photo, not mine):

 

[B2]

Hi @verbotenwhisky

Interesting concept. Looks like you are going to spend some $$$ for the Dividing head. I have a 4th axis on my 940M CNC machine. So it is basically a 3 jaw chuck with motor and mount so that it "sort of" looks like the Dividing head geometry including the tail stock. It is made just for doing this sort of thing where the CNC machine turns the 4th axis part as the x-axis (or y or z axis) moves. I have never had much need to use it.

You wanted thought alternatives:

If you want to keep your power feed then you might think of putting an optical encoder on the x-axis lead screw to feed a small box of electronics which then drives a stepper motor driving the Dividing head. In fact, you do not need the gearing of the dividing head as you could do that in the electronics box so maybe you could trade off some of the cost of the Dividing head (for a cheaper chuck) and buy the stepper motor. I guess this would sort of be the equivalent of the Electronic Lead Screw (ELS) for lathes . There an encoder on the lathe spindle provides a position to the ELS logic which then drives a stepper connected to the lathe lead screw gear box. Lots of info on the ELS on the forum and You Tube by Clough42. He even sells a kit. Google "clough42 els kit" for info.

Good Luck,
Dave L.

 

[verbotenwhisky]

Hi @verbotenwhisky

Interesting concept. Looks like you are going to spend some $$$ for the Dividing head. I have a 4th axis on my 940M CNC machine. So it is basically a 3 jaw chuck with motor and mount so that it "sort of" looks like the Dividing head geometry including the tail stock. It is made just for doing this sort of thing where the CNC machine turns the 4th axis part as the x-axis (or y or z axis) moves. I have never had much need to use it.

You wanted thought alternatives:

If you want to keep your power feed then you might think of putting an optical encoder on the x-axis lead screw to feed a small box of electronics which then drives a stepper motor driving the Dividing head. In fact, you do not need the gearing of the dividing head as you could do that in the electronics box so maybe you could trade off some of the cost of the Dividing head (for a cheaper chuck) and buy the stepper motor. I guess this would sort of be the equivalent of the Electronic Lead Screw (ELS) for lathes . There an encoder on the lathe spindle provides a position to the ELS logic which then drives a stepper connected to the lathe lead screw gear box. Lots of info on the ELS on the forum and You Tube by Clough42. He even sells a kit. Google "clough42 els kit" for info.

Good Luck,
Dave L.

That is an interesting alternative....

 

[mattthemuppet2]

have a look underneath to see what kind of gear is on the end of the leadscrew. It might be possible to interface with that gear through the top surface of the powerfeed

 

[benmychree]

I would get a Servo feed unit and mount it on the right hand end of the table, and modify the end of the feed screw to mount the change gears.
I have an original B&S universal dividing head with all the bells and whistles for spiral milling and have used it many times.

 

[verbotenwhisky]

I ordered a universal dividing head from Precision Mathews, it will be to me Friday at a shipping weight of 200 pounds, and I am a bit excited. I need the dividing head for a little project I am working on, but bought the head which has gears that connect to my X-axis lead screw so I can cut spirals, worm gears etc... No, I didn't need all that functionality, but my future is bright as I now have it and the cost wasn't terrible, it was reasonable.

I am still working on a solution for the X-axis power feed, I know the one on the mill makes a nice drink holder but the more I think about it the less I like it and its in the way. I am seriously thinking about modifying the power feed from a Knee Mill which fits on the right side and hangs down, if this option allows the manual crank to remain on that side as well I would look at that as a bonus because I would love to have a crank on either side of the table and a power feed under normal operations and a place to mount the head when I need it.