How is a Volstro slotter head built?

[Mud]

We're considering building a slotter head for our VMC that can be run by the spindle. I'm curious about what the Volstro heads look like inside, hoping I could scale up the mechanism for what I want to do. I need about 2.5 to 3" of stroke for a 3/8" wide slot, and the work is fairly light duty but heavier than what a volstro is built for. The stroke does not need to be adjustable. I've never seen one in person - Has anyone here had one apart, or do you have a manual for one showing an exploded view? Do they have either a relief mechanism or a clapper?

[jabezkin]

I think one of the ones in the "for sale" section showed some pictures of the inside.

[lazlo]

I saw one for sale on Ebay, and it was the typical Scotch Yoke setup, running on dovetail (or maybe box) ways.

You might look at the VersaMil shaper attachment -- same basic design.

[gwilson]

I was going to make one,drew up sketches for how I thought it should work inside,then found 1 for sale. It was just like my concept inside! there is a steel cylinder with a curved groove milled around it. the cylinder runs inside a cylindrical hole that fits it loosely enough to let it run. A cam follower runs in the groove,and is connected to a vertical ram. You grind lathe type HSS tools and set screw them into the groove. I THINK the groove is 3/8". haven't used it in a while. I made a hardened piece of 3/8" steel with a 1/4" groove milled into it to hold smaller bits too.

The stroke is 1" It is not a real heavy duty unit,as are most Volstro items. I wouldn't crowd it into taking much except light cuts.

I like it as it is light weight,and easy to mount over a Bridgeport spindle.

[ivymcneil]

Hi Mud
I have a volstro booklet and parts list, it has a very good print in it.
I will dig it out and scan it for you.
Ivy McNeil

[gbent]

Can you just put the tool in the spindle, command the spindle TC position, and cut it in rapid? G91 and a loop counter and your done. Works good to cut tapered or blind keys that usually require fixtures.

[Mud]

ivymcneil - Thank you! PM sent

gbent - yes, I'm already doing that to other parts in a lathe op and have PH Horn carbide tooling for it. This family of parts has 12 slots in each piece, would take too long and wear out the ballscrew to do this way. I'm doing them in a vertical slotter now. I'm also toying with CNCing the slotter, this VMC attachment way would allow me to do multiple ops in one fixturing.

Thanks for all the replies. I pictured using a drum cam, this tells me it could work.

I also have a Bridgeport E head slotter I bought from Barry Weeks, I'm toying with mounting it to the side of the VMC head on a bracket and turning it on and off with an M code. The spindle driven tool could be small enough to change with the toolchanger if I keep it under 5" dia.

[ivymcneil]

Mud PM sent,
Ivy McNeil

[ivymcneil]

Hey Mud
I looked at my Volstro literature and figured out what you were asking about.
I have used almost all of their tools but that one.
Sorry I could not help you.

Ivy McNeil