Chester Super Lux / RF45 clone / Square Column mill spindle dimensions.

[Taf_PembsParticipant @taf_pembs]

Hi All,

I have a Chester Super Lux that I am attempting to 'make good'.

If anyone has a similar mill – RF 45 clone type that has an R8 Spindle would you mind measuring the wall thickness of the spindle at the nose please?

Also, how far does the nose protrude from the lower cap?

Mine is a Morse Taper 3 but having to tap out tooling all the time is something I'm really not comfortable as each hammer tap is driving straight through the bearings which will be new.

I am considering regrinding it to R8 but this will only leave a minimum wall thickness of just about 5mm right at the nose (and that is starting the taper right at the nose so including the key slots) and again at the narrowing for the lower bearing seat with the rest obviously having more meat.

These mills all seem to be supplied now with an R8 spindle as standard but still seem to use the same bearings but other than Grizzly in the States that want lots and lots of penny's for one I can not find one anywhere else for love nor money.

Unless anyone knows where one might be purchased?

If not an option I saw someone suggested the modified drawbar route that could be an option.

Hope all are well..!

Cheers

[Taf_PembsParticipant @taf_pembs]

[old martParticipant @oldmart]

You would have to remove the spindle to measure it properly, and I doubt if there is enough metal to convert it easily. The minimum bottom diameter of an R8 spindle would be 1 5/8".

**LINK**

Edited By old mart on 08/02/2023 17:53:30

[Taf_PembsParticipant @taf_pembs]

Hi Old Mart,

Cheers for that, 1 5/8 is almost exactly what my spindle nose is OD, its 41.52mm so a gnats' over.

There is plenty of meat up the spindle for the parallel 0.949. Might just get away with it!

My spindle is stripped, was hoping someone might be able to just measure the wall thickness at the spindle nose & stick out incase the R8 version is a little longer and has a larger OD nose section or is it just a different grind of the same shaft.

From Grizzly's Part No Image the nose looks a little longer – Grizzly R8 Spindle

[JasonBModerator @jasonb]

Don't know about the RF45 clones but my Sieg with R8 is about 30mm longer than the MT version and a good 60mm OD so the R8 taper does not get as far as where the lowest bearing comes.

You can see the difference in the two exploaded parts drawings

Been happy knocking out the tooling on my MT3 mill for the last 15yrs with no bearing problems.

Edited By JasonB on 08/02/2023 18:43:53

[old martParticipant @oldmart]

I changed the MT2 spindle in the Tom Senior light vertical to R8 which was done by using the original splined top half attached to a new R8 spindle bought from ARC which was for one of the SEIG mills. An extension to the quill was added to accomodate the larger bottom bearing.

[Taf_PembsParticipant @taf_pembs]

Thanks JasonB, it does show quite a difference there..

I just thought that if I'm going as far with it as I am then I may as well do this before spending any money on tooling for it.

[Taf_PembsParticipant @taf_pembs]

Posted by old mart on 08/02/2023 19:40:34:

I changed the MT2 spindle in the Tom Senior light vertical to R8 which was done by using the original splined top half attached to a new R8 spindle bought from ARC which was for one of the SEIG mills. An extension to the quill was added to accomodate the larger bottom bearing.v

That's a fine job

I did look at the dimensions of a std replacement Bridgeport spindle, there seems to be plenty of them about to see if it could be '' but although 6 spline I cant find any dimensions of the splines and the distance between bearings is about 30 odd mm to short.

I might just try and knock one up from some bar for a practice and see how feasible it is.. be a few weeks yet, still got a wrist full of stitches.. and a belly full of codeine!

[old martParticipant @oldmart]

If you do go for the modification to your spindle, get a couple of R8 arbors to use as gauges for when you bore the parallel end, you need the best sliding fit, not size for size, or you will have difficulty fitting and removing the arbors. Also you might decide to dispense with the location pin in the spindle, both the mills at the museum do not have it and nobody misses it. Yuy might notice spanner flats near the end of the R8 spindle photo, this is very useful and both our mills have it.

There are ways of making a captive self extracting drawbar in MT3 spindles which might be worth researching. Start a new thread on the subject, many people have clever ways of breaking the taper.

[Taf_PembsParticipant @taf_pembs]

Cheers for that Old Mart, I have read that a lot of folk seem to dispense with the pin.

It's a shame the Machinery's Handbook only gives the Male R8 dimensions but that is good enough to get the female dimensions.

Eye, as I said at the end of my first post, if this becomes too much of a mission then a modified drawbar would by the other option. Not my preference but would do.

Thing is, now it's in my head, its become a challenge!

[Robert ButlerParticipant @robertbutler92161]

I use a "windy" spanner to losen the drawbar which also frees the taper. Make sure there is something to catch the tooling before it hits the table!!!!! AMHIK.

Robert Butler

.

[Taf_PembsParticipant @taf_pembs]

Thanks all for the replies and suggestions, appreciate it!

After a fair amount of looking and the wonders of google, the butterfly air impact gun option never entered my head and more to the point I didn't realise they could be picked up so cheap so once the mill is rebuilt I think I'll leave the spindle alone and go down that route.. seems very effective!

Cheers!

[Cabinet EnforcerParticipant @cabinetenforcer]

There are scattered reports of people replacing (usually) MT4 spindles with an iso/bt type.

The most recent one I have seen was by youtuber Stefan Gotteswinter, he put in an iso30 spindle. Covered in the first 10 mins of this video :

**LINK**

The spindle was obtained from a german machine dealer, **LINK**

I would like to get around to this myself someday, an iso holder would be so much better for quick changing, it seems maybe even iso40 is possible to fit.

[Robert ButlerParticipant @robertbutler92161]

It also solves the problem where there are no spanner flats on the tooling and no spindle lock.

Robert Butler

[Author]

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