Clausing 5900 Collet Holder photos

Someone asked that I publish photos of the Royal 5C collet holder that came with my Clausing 5914 lathe, to help in the home-shop manufacture of a replacement. I also measured the major dimensions with a caliper and documented them in the text file.

I have posted the photos on the dropbox at the following locations:

The photos are 1.7 Mbytes each, and are pretty clear.

Joe Gwinn

Reply to
Joseph Gwinn
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Thanks Joe, that was me. Yes, I think I'll make mine out of CI or steel. Thanks for indicating that yours is AL, I kept looking at the pictures and thinking that isn't cast iron. (Finally I read the notes ;) )

I see your collet pin is missing from your adaptor. Mine is sheared. Have you toyed with putting a new one in? I've lived with a bridgeport with/out one for ages so I suspect I'll live w/o one in the lathe too.

So are the threads being damaged pulling out the collet adaptor? From the looks of things the nose protector is also used to pull the collet adaptor.

A ruler in the picture is priceless!

I made a bit more progress on reparing my driven hub sheave in the last week for my 6903.

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Thanks again,


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Of course not. It's a really really bright kind of steel. And very light. But weak.

There was a sheared-off stub that I punched out when I cleaned things up.

When I suggested to the guy at Royal's Tech Support that I'd do without the pin (based on my experience with R8 mill spindles), he countered that it could be a real problem in a lathe if the collet unscrewed and loosened, releasing the workpiece while being machined. So, I'm tempted to replace the pin, which he suggested that I make from soft mild steel wire. It does not look difficult or expensive. Nor is precision required -- it's almost blacksmithing.

That said, I doubt that I'll be anywhere near aggressive enough to unscrew the collet anytime soon. But it would make a mess.

Yes, that's exactly the problem. I don't think I'd make the nose out of cast iron either, as I bet CI threads will also fracture if the nose is used for forcing the holder out of the spindle taper. CI is just too brittle. I would also change the design, reducing the space between the back of the holder and the face of the nose such that more threads are engaged during the forcing operation. On my unit, the gap is worth at least one turn of the screw.

The Royal fellow suggested a cylindrical bar and a hammer, applied from the back, to get the holder out. I used a piece of 1" black iron pipe as the bar, and banged it with a steel hammer to pop the holder loose. The 1" pipe has an OD of about 1.25", which is adequate, but a little loose in the 1-3/8" spindle bore.

Actually, I did both: I tensioned it by using the nose to apply some force to the holder, and then banged on the back of the holder with the pipe and hammer.

If one uses a solid bar, it should weigh as much as the hammer head, for best transfer of momentum upon striking. One wants to do this in a single hammer strike, so we don't batter the spindle. So no undersized hammers need apply.

Yes. I don't know why people leave the ruler out. It's not like we don't have many such rulers scattered about our shops.

Did you machine these from raw stock?

Joe Gwinn

Reply to
Joseph Gwinn


It probably is not too much of a problem if you have a short enough headstock so you can hold the collet in place with one hand while you unscrew the drawbar with the other, but sometimes the collet threads can be a bit difficult to turn in the drawbar. In particular, I found a

5C-mount 4-jaw chuck (about 4" IIRC) to be particularly tight in my drawbar. (Chinese manufacture, of course.)

However -- if you have a lever style collet closer, the closer is locked to a toothed disc on the end of the spindle (once set), and the assumption is that the collet will also not turn while you're changing parts. Otherwise, the tightness of the collet when you lock up will vary -- as well as perhaps the collet being too tight in the released mode so you can't get stock into it.

My adaptor has the pin, and if it did not, I would make one to fit it.

I think that mine is about the same -- perhaps a bit less, but it has shown no problems so far. Perhaps yours was dropped too often in its prior life, which could start the end threads cracking, and leave too few for the ejection function later.

I've only driven it out *once* -- back with the 2-1/4x8 spindle, before I figured out what the threaded ring with the pin spanner holes was for. (It only took once. :-) And that ring was steel.

Hmm ... I've seen the draw-up rings with differing lengths. Perhaps mine has more than yours does, so there is less thread engagement when you use it to pop the adaptor out.

You could turn up a ring which took up most of the gap between the collet adaptor and the nose protector when fully tightened, and either put it on before you put the adapter into the spindle, or cut out enough of it to leave a 'C' which would slip on the assembled spindle/adaptor combination, so you would use more of the thread engagement.

Ideally, it should be both inch and metric, to cover everyone who looks at the photos.

Good Luck, DoN.

Reply to
DoN. Nichols

I'll probably do that when I get the rest of the stuff fixed.

I don't see any marks that would suggest that the nose was ever dropped hard enough to bust a 6-tpi thread.

The length is 1.875" and the diameter is 3.5" (excluding threads). How long is your nosepiece?

I could, although the threads are probably all weakened, judging by the busted threads. If I made a new nosepiece, I think I would used steel.

I have a ruler like that. Very annoying ruler that - always the wrong scale on the edge you want to use. Maybe it's destined to be a photo model, despite the total lack of curves.

And Clausing would object - this 1972 machine is all inches all the time.

Joe Gwinn

Reply to
Joseph Gwinn

O.K. Perhaps just age.

[ ... ]

First off -- the length of the draw-up ring from the face of the headstock is 1.25" That was what I was talking about the length of -- the ring which is captive on the spindle.

Now -- the protective nosepiece:

3.492" (close enough to 3.5" exclusive of the threads. 1.875" over-all length.

The main difference is probably that mine is only about eight years old or so. I bought it (and the adaptor) new from Royal through Scott Logan when I got the L-00 spindle and headstock.

As might I if I make one now that I have something to show me what it should look like. :-)

But I would be likely to line it with aluminum for the part which contacts the spindle nose, so if I am ever careless enough to trap some chips in there, it will be the spindle nose protector instead of the spindle nose itself which will get dinged. :-)

The wrong scale, and/or reading from the wrong end. :-)

Well ... I have the metric threading gears for it (really for the 5900, but they should work here, too), but so far I've been able to do my metric threading either on the Compact-5/CNC (just flip a switch to 'mm' from 'inch') or with the proper chasers in a geometric die head on the Clausing -- no leadscrews involved. :-)

Enjoy, DoN.

Reply to
DoN. Nichols

They sound identical to me.

The spindle is hardened, so a mild steel nose ought to lose the fight.

I already have lots of such dings on the female taper in the spindle and the male taper on the 5C collet holder. One thing on my list is to stone the ding-induced bumps away. I have a few ideas:

  1. Tapered cone arkansas stone in hand, used on the female tapers. Flat stone used on the male tapers. Used with hi-spot blue.
  2. Mate the pieces by using very fine Clover grit-in-grease to lap away whatever sticks up.


I will someday want metric threading gears, but first I will learn how to thread on this lathe. I engaged this function tonight, generating a

10 tpi left-hand shallow thread, The carriage moves rather faster than is comfortable if one is moving towards the headstock trying to cut a right-hand thread. I see why people sometimes thread on the back with the spindle running in reverse.

Joe Gwinn

Reply to
Joseph Gwinn

Yes -- but I expected them to be identical. It was the length of the captive pull-up ring on the spindle (and thus its number of available threads) which I was talking about.

[ ... ]

Are you *sure* that it is hardened? I know that the taper in the tailstock yields to a No. 3 Morse Taper reamer to clean it up, as I have done so.

Hmm ... I think that it is likely to wedge and break in the taper.

What I will do when I finally get around to cleaning up the tapers in my lathe is:

1) Mount the taper attachment. 2) Spend a lot of time tuning it to match the internal taper. 3) Mount the toolpost grinder (along with protecting all of the ways) and use it to clean the inner surface. 4) go back to (2) above, and reset it for the external taper, and then repeat (3) as well -- with the key removed of course.

Mate *which* two pieces? Remember that you have multiple things which the spindle taper must match, so match lapping would make one chuck type object fit the spindle, and leave the rest uncertain.

I wish that I could find a 4-1/2 MT finish reamer, and a matching set of male and female gauges. Then I could be sure that the taper attachment is set properly, and also properly test the fit of the spindle's internal taper. It is no fun that every Morse taper is a little different. (Though IIRC the MT-4-1/2 is the same as one of the two adjacent tapers, since it came along after the Morse Taper series had been around for quite a while. -- Nope -- a quick check in _Machinery's Handbook_ shows that it is precisely the same as the No 7 Morse taper -- so I can't even get away with using the small end of a No. 5 MT reamer to clean up a stub 4-1/2 MT. :-(

[ ... ]

Yep -- 10 TPI is a bit sudden. The slowest belt speed with back gear on my 5418 makes it doable -- but only with a bit of practice and a somewhat wider run-out groove.

Start with the tool disengaged and far enough back to handle clearing any shoulder you might hit, and practice engaging and releasing the half-nuts until you feel comfortable with it. IIRC, my slowest spindle speed is 50 RPM -- at least until I add a three-phase motor and a VFD to it.

By the time we get to about 20 TPI, I can do it at more reasonable speeds.

But you can cut away from the headstock by mounting the threading tool upside down -- you don't need to put it in back.

Enjoy, DoN.

Reply to
DoN. Nichols

The ring? Now it makes sense. Not that I want to replace or take the headstock apart just yet.

Hmm. No, I have not tested it. But I'd bet that it is hardened, given its manufacture and age. That isn't to say that the spindle will be glass hard. It's probably hardened for some optimum combination of toughness and resistance to surface damage. Like dings.

I didn't describe it well enough. I'm thinking one of those tapered half-round stones used by hand, with the spindle rotated only by hand. The stone would not fill the taper.

Or the flat side of the tapered half-round stone.

I don't yet have a toolpost grinder.

Well, actually I do, a partial kit inherited from my maternal grandfather. It's a Dumore model 11G, and is too old for Dumore to have parts. It gets quite hot when operated at internal grinder speeds, and seems ready to achieve thermal runaway. I haven't figured out what's wrong just yet, but I don't know that all the parts I have really go together. The spindle seems too tight when things are fully seated, but I don't know what a Dumore spindle is supposed to be like.

Does anybody have the patent numbers for the old Dumore toolpost grinders? I bet the clue is in those patents. In those days, patent numbers were likely to be in the manual and/or a label. Alternately, does anyone know the name of the inventor, perhaps also a founder of Dumore?

I didn't fully explain. In this approach, one mates a collection of items to one another in random pairs, thus forcing them to achieve a common mating-surface shape. It's an extension of the process that one uses to originate surface plates by scraping three plates into mutual conformance.

In the present situation, the pieces are already almost in conformance, and the theory or hope is that the dings will be preferentially ground off first.

But a MT #7 reamer would work to clean up the female taper in the spindle? There is certainly enough room in back, deep in the spindle.

I do have a VFD, so that may b my solution. The only disadvantage found so far is that if I engage the 5914 clutch with the motor running, the power surge required to quickly spin all that metal up to speed causes the 3-HP VFD to trip, complaining of overcurrent. This, with a 2-HP motor.

So, I put the lathe in gear before starting, and let the VFD ramp the speed up, using the clutch only for stopping. I'm getting a "clutch kickout" block as well. This clamps to the square clutch rod, and disengages the clutch if the carriage attempts to run past the block. This will be used to cut down on crashes.

Ah. This sounds more practical. The crossfeed on the 5914 doesn't seem long enough for convenient cutting on the back side, especially with large workpieces.

Joe Gwinn

Reply to
Joseph Gwinn

I won't go into too mush detail here but...

My 5914 came with the Royal lever closer, but no adaptor or nose ring...

FWIW the Royal lever obviously wasn't original equipment on the machine... the arm that the lever piviots on is "homebrew" and hooked to one of the cover studs, not back around to the headstock.... even so it works great.

I got an adaptor (NOS, in the box) on FleaBay for $25 and made the nose cover.

I made my nose cover out of AL. I just measured the LOO spindle and made the inside of the ring slightly larger so it dosen't 'grab' the taper. I made SURE it bottomed out on the threaded spindle ring and then did trial and error fitting on the front till a 0.010 feeler would fit between face of the nose cover and the back of the MT4.5 - 3 Adaptor It's worked great for well over a year.

And trust me that lever will pull a collet AND that adaptor in tighter than ... well you know.. :-)

Oh and yeah get a Royal lever, hand wheels are a joke...

--.- Dave

Reply to
Dave August

Levers would be nice but most HSM'ers can get by with a hand wheel. Now in a production situation, levers rule. Money is time.


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Thanks. I'll start there. Otherwise, far too many choices.

Yes. Carbide is far stiffer than steel. I've also seen boring bars with built in vibration damping systems, which allowed extremely slender bars to work.

And the latest chapter is using a #50 drill in steel, on the Millrite. I simply could not feel what was going on -- machine too large, bit too small. So I used one of those "sensitive" chucks held in the Millrite spindle, and this worked, although it took a lot of finger force for the brand-new #50 drill to bite and produce long curly chips.

That ought to do it.

On my Mac, I find that Firefox doesn't show the videos on YouTube, but Safari works properly.

The Aloris boring-bar holder would be the approach I would use.

That's quite the gadget. Maybe someday. Hmm. After the taper attachment. But I see why it would be used in production.

I bet one could make a replacement Nut Holder Assembly fairly easily.

Hmm. The Shooting Star DRO uses a rack and pinion, and so is far less sensitive to alignment than an optical encoder. One may be able to clamp just one end of the rack. The Newall Spherosyn also has this property.

They don't mention dedicated conversion chips because people instead use commodity comparitor chips for this, and these chips are plentiful. The main trick is to design in some hystersis, as the edge speeds are quite low, and the comparitor will oscillate without hystersis. The other trick is to choose a chip with separate analog and digital ground pins, for better noise isolation.

I'm talking about the display head, not the reader head.

The story of our lives for sure, as we work on machines from our childhoods.

Joe Gwinn

Reply to
Joseph Gwinn

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