Retrofitting a 1986 Maho MH400E

IDK what the new rebates are for Haas machines, but when I was considering my options before getting the MAHO in late 2017, a Mini Mill was 25% off from our local distributor (something like a 25% off for 25 years in business kind of deal).

That price put it at over 3x the cost of the MH600E, even accounting for the expenses associated with my crayon copy of Mark's retrofit. At this point I could probably send it off to a rebuilding company for way grinding, scraping, painting and general mechanical maintenance and it would still come out cheaper than a new Haas at a discount.

Glemigobles wrote: Interesting design Andy. What would the output torque look like without gears?

I don't know

But the Variator in my lathe was not dissimilar in theory of operation and could transmit 3hp continuous. The original supercharger application transmitted enough to do that job too. I think that rather specific oil might be needed for best performance.

Ooh, there is even a picture of the same arrangement on the bottle!
www.amazon.com/Rotrex-R50-S150-OIL-Super...-Fluid/dp/B00BV65EVC
Description of how it works here: www.dieselnet.com/tech/air_super_drive.php (now that I know it is a Rotrex drive)
Also interesting is that the slightly elaborate slottted axle arrangement I had is not necessary or helpful. Undersize shafts work better.

And here is the patent which explains how it all works.
patents.google.com/patent/US6960147B2/en
Maybe I do need to build one

Maybe you can sell me one when you do

It's an interesting concept, and I'd love to have the machines necessary to build one and try it. From what a tool maker friend of mine said, mechanical speeders are really loud, this design might be a little quiter perhaps?

The other day I found an ebay auction listing a set of 3 electric spindles, all of which could be mounted on one's preferred toolholder size (40, 50), complete with an inverter. Two were 40000 rpm at 4kW, and one was 15000 at 12 kW. The price was around 5000€, but that's how much a single Air Turbine costs from Hoffman (and those require expensive air compressors to run reliably). There was also a gizmo for setting the speed. I just hope that I'll keep finding such interesting offers when I have more money again!

Another speeder with friction design.

The springs force the balls to make contact with the races