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A horizontal boring mill/lathe project

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S_J_H:
It all started when I saw an ad on craigslist for a Russell T. Gilman box way slide. I found the slide to be like new with no wear at all. This is a high end machine slide, made in Wisconsin, USA. SKF bought them out a while ago.
The slide is made of meehanite iron, hardened and ground ways, fully scraped in surfaces on the table slide along with anti-friction coating.
It weighed in at around 200lbs and around 36" long. It is accurate to within .0005" over a 36" span.
This would become the z axis and foundation for the entire machine.





Continued-

S_J_H:
So I decided I wanted to try and make a machine capable of line boring, be usable as a horizontal mill as well as a lathe. It would be cnc'd as well.
I did not create any cad drawings and built this machine on the fly. I was using this machine as a sort of guide.-


 I used a mini mill headstock and installed better bearings in it. I machined the box way slide and mounted a mini mill z-axis column to it.
I mounted a dovetail way to the side of the mill head and made a z-axis acme screw system.
I now had a headstock with about 8" or so of travel. I mounted another mini mill column on a slide table to the right of the headstock and cross slide table. This would become the outboard support for work and/or line boring bars with the same amount of travel to match the headstock.



Continued-

S_J_H:
So now we'll jump to the end of the project,
The machine is cnc'd presently in 3 axis. The table x and y and the spindle is cnc'd for continuous or indexing machining.
It's a cnc boring mill,indexer and lathe.
The planetary gearbox drives the spindle for 3 reduction ratios and a 4th higher speed which bypasses the gearbox.
The machine has a good rpm range from 0 to 2900rpm.
The spindle has a ring gear on the left hand side and a stepper motor is mounted on a eccentric with a worm gear drive. Rotating the stepper engages the spindle and locks in place with a detent ball.
The outboard column is used to support line boring bars or arbors for horizontal milling/sawing. It is fully adjustable to keep the work or tooling straight and uses a rack and pinion for movement along with a fine feed. Bushings are replaceable to suit whatever size needed.
The headstock uses a acme screw and delrin nut and is pretty much backlash free.

The headstock also has a separate brace to further improve rigidity. The deflection at the spindle end is better that my x3 mill.
The long axis is driven by ballscrew with dual preloaded nuts. The cross slide is driven by the same arrangement and also use linear rails/trucks. This is going to be changed soon to a much larger table and dovetail ways.
I also built a separate mill/drill head with a quill that can be mounted on the table for many uses. I made it from an old drill press head and made a new spindle with integral 3/8" endmill holder and good bearing support.

The machine-








Here is a video showing the planetary drive system in action-


Here are some of the very first videos of it in action in lathe mode-


Steve

Bernd:
Steve,

Thank you for a most excellent post. You are truely a very talented person. From design to building that machine is a true example of Mad Modding. I  :bow: to you.

Your machine reminds me of the large line boring machine they used at the place I worked. What keeps the table on the rails, just it's weight? Interesting idea using two mini mill columns for the Z-axis.

Again great work and thanks for the time you took to post.

Bernd

chuck foster:
very impressive  :bugeye:

it looks like you have built machines and done some cnc work in you time.
can't wait to see what you make with this machine.

chuck  :wave:

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