Spindle speeder - overhaul and metricify(?)

What?

Some years ago I acquired a "speeder" device from the late John Stevenson. These devices cause a milling toolholder to run at several times the spindle speed, by means of an epicyclic gear stage. This way you can run small cutters at the correct speed on a large spindle.

In my case, The Shiz is limited to 6-7000rpm (officially 6000rpm but I have set my VFD to 7000rpm). This speeder has an allowable max speed of 12000rpm, so would allow me to double the maximum usable spindle speed.

This one is by an unknown French manufacturer called "PBC" but it seems to be in good running order. The main issue is that the drawbar thread is imperial (presumably 1/2"-13, making this an NMTB40 tool) rather than the metric M16 of an ISO40 machine. 

I can't find any useful mention of the thing on the internet but beyond understanding how to dismantle it, that's of no consequence. The only hit was on a machinery sales website. The one thing it tells me is the date of manufacture (December 1965 for this example) and the option for different spindle tapers - this appears to be MT3 or similar.

There is only one way to fix this NMTB / ISO issue, namely to chop off the threaded nose and weld on a metric replacement. Sounds drastic and (on the face of it) unwise but in fact this feature is only required to connect to the drawbar, so precision isn't a critical requirement. Besides, I've previously done this on several NMTB40 and BT40 toolholders without issue. Furthermore, as a "never heard of" brand, this device has little commercial value and I'd also like to use it.

Let's strip it down, clean it up and get it ready to be rebuilt - once the threaded nose has been replaced of course.

Stripping down:

With the "top" cover removed, the main housing comes off, revealing the ring gear and the 2 planetary gears. The housing contains 2 large deep groove ball bearings from SKF (16014 size, ie 70 x 110 x 13mm). The short arm protruding from the side of the housing is used to prevent the housing from spinning.

The overall ratio is 4:1, so the sun and planet gears are the same size (24 teeth) and the ring gear will be 3 times that (ie 72 teeth). The ring gear has one of those 16014 bearings on each side.

With the retainer plate removed (six fixings), it's possible to drive the output shaft out from the input shaft.

The output shaft runs on a pair of back to back bearings and a needle bearing. I will need to remove the circlip holding the needle bearing, spacer and sun gear before I can loosen and remove the lock nut and then remove the bearings. 

And now that the output shaft has been removed, the planetary gear yoke can be removed through the radial slot.

The plate with the six fixings is what holds the bearings for the output shaft.

Here's the depopulated input shaft.

So I will need to grind / cut off the imperial threaded taper nose, machine it square and prepare it for welding an M16 nose.

The output shaft has a Clarkson Autolock style nose. There is an ER11 collet chuck on a 16mm diameter body with the appropriate thread to mate with the lock nut. So I can use any cutter that can be accommodated with an ER11 collet ie up to 7mm dia.

Lastly, the output shaft needs to come apart. These Knipex grippers just fit the spanner flats.

..with the locknut held in the vise.

Cleaning up:

Brand new ultrasonic bath with a mixture of Gunk and Jizer seems to a decent job of removing the crap and grease.

Here we are with the cleaned up input and output shafts and the outer (fixed) ring gear. They are in good nick and beautifully made.

Input shaft:

Output shaft:

Autolock-type collet and various fixings:

The bearings cleaned up well and are in good shape.