Author Topic: Headstock Spindle Back Stop (Read 15048 times)

PeterE · « **on:** November 13, 2012, 04:33:21 PM »

Seeing or reading about attachments and accessories that can/should/is required when making stuff in my workshop always starts a kind of solution process. At this time it started off when I read about and saw Stilldrillin´s (Dave´s) simple back stop for the spindle. I will need something like that in a while to make the support pillars for the Trojan.

Dave´s idea is just one of several, and I have the GHT workshop book with another solution. The third version appeared in MEW as an extension for the C3 headstock dividing attachment. Hmmm I have to make a choice

What I want to achieve is something that answers as many as possible of the following:

Easy to both attach and remove
No banging or thumping to spare the spindle bearings
Wide range of length making use of as much of the 215 mm long spindle as possible.
Includes a dividing gear that is positioned to utilize the already existing stop.
Can be exchanged for a back-end spider for long pieces.
As large diameter as possible.
Easy to make on the C3

The internal diameter of my spindle (C3) is 20,5 mm so around 15 to 16 mm free inner diameter all through the spindle would be good. The chuck end MT3 taper ends 70 mm in from the chuck and is around 23,7 mm at the edge.

My thought is to go the GHT way by making a "pipe with 15 mm inner diameter and just under 20,5 mm to pass through with a shoulder 25 mm diameter at the front end. The back end is a large nut with a 60 tooth gear attached and attachments for either back-stop or spider. Something like below.

Picture went bad

New coming tomorrow as drawing is on another machine (at work). When picture updated in P-bucket it will automatically show.

I hope you can de-cipher the sketch. It is not finished yet as this is where the idea stopped for the moment.

Comments?

BR

/Peter

Fergus OMore · « **Reply #1 on:** November 13, 2012, 05:15:46 PM »

Two more books- Peter

One is GHT's Workshop Techniques- which brings in Dividing and Graduating and then GHT's old friend Jack A Radford from New Zealand's book.

What you really have is in Classical English- a Nest of Singing Birds- all inspiring each other.
Chaddock, Cleeve, Tubal Cain, GHT, Ned Westbury, Bradley, Hallows and dear old Sparey.

My collection of earlier references went to the 'poubelle' today but I kept my Hozapffels-- just in case.

Worth every euro!

Jonny · « **Reply #2 on:** November 13, 2012, 06:46:11 PM »

Does the spindle protrude at all?
If so could clamp up off o/d that and in turn not limit what you can get up the spout.

PeterE · « **Reply #3 on:** November 14, 2012, 10:26:42 AM »

Fergus,

I have both the GHT Workshop Techniques and the Radford Accessories to your lathe. Goldmines in ideas!

Jonny,

Very good comment!

I know th free end at the back end of the spindle (to the left in the picture) is only a short piece, somwewhere around 5-ish mm or so. It has a 27x1.5 mm thread asused for the spindle lock nuts.

But the idea is very worth looking closer into. Have to measure a bit more because the existing distance is a bit short really for a good and secure grip by just threading, it would probably need something to lock the "nut" if used.

Hmmmm.

Have to think a bit more ....

BR

/Peter

PeterE · « **Reply #4 on:** November 16, 2012, 01:14:49 PM »

Had to find out more closely on how it actually looks and to get some measures.

As can be seen, the end of the spindle only protrudes a small amount after the spindle lock nuts. The protrusion is 3.7 mm or about 9/64-ish. With a thread having a pitch of 1.5 mm that would make two threads which I regard as far too little for a useful grip.

I have some memory of at least three threads to get a good grip but preferable more. To get more space I could of course thin the lock nuts a shade. As delivered they are 7.5 mm wide (5 threads) each. If I thin them down by 1.5 mm (1 thread) I will get just over 6.5 mm free end (=4 threads) which well could work.

I really do not want to exchange one of the lock nuts for a special as my though with the attachment is to make it detachable and exchangeable for a similar with other functionality. With this in mind, a screw-on attachment with a separate lock (set) screw would probably work.

If that route is not the way to go, I think I will stick to my original idea, hmmmmm

BR

/Peter

andyf · « **Reply #5 on:** November 16, 2012, 02:11:03 PM »

My lathe has only a single nut there, Peter. It is locked in place by an M4 grubscrew (I added a bit of brass under that, to protect the threads on the spindle).

Could you do something similar and use only one nut to expose the original 3.7mm plus another 7.5mm of the M27 thread?

Andy

Stilldrillin · « **Reply #6 on:** November 16, 2012, 02:13:40 PM »

Very good thinking Andy!
I was going to suggest mounting on the o/d of the nuts. I also have a couple of spares, if needed......

David D

Jonny · « **Reply #7 on:** November 16, 2012, 03:42:36 PM »

Looks to be the quickest and simplest way as David said, it wouldnt need to be cock on accurate any way.

Other than that remove the lock nut and thread up the bore when screwing back stop on to act as a locknut.

Either way you wont loose any spindle bore.

PeterE · « **Reply #8 on:** November 16, 2012, 03:53:37 PM »

Hi ,

Andy, Thanks for that idea

That sounds like a good way forward. getting between 10 and 11 mm at the end of the spindle makes a huge difference in stability! Is the nut hardened or toughened or neither?

David D, Mounting on the outside of the lock nuts is of course a possibility, but I want to be careful with the sizes as I have made a simple dividing contraption that I though I could get into play here as well. That is why there is a sketched 60t gear in the line drawing above.

... and to Jonny who wrote while I wrote ...

Agree with you that David´s idea is the simpler, but I think Andy´s is (at the moment) coming closer to what I am thinking. And you are right I will not loose any spindle bore, just have to be careful to make the setting rod in a way that it will not slant when reaching the MT3 taper.

Thanks for all input

Have to think on for a couple of days and finish the tiling of the guest "bathroom" so it will be ready before X-mas.

BR

/Peter

andyf · « **Reply #9 on:** November 16, 2012, 05:27:31 PM »

Hi Peter,

My nut isn't hardened in any way, but yours might be. I doubt it, if your lathe is Chinese like mine. You can soon find out; try scratching it with an HSS tool.

The grubsrew on mine is original, but I think I prefer it to lock nuts. The lathe came with taper roller bearings, and adjusting the preload with no instructions is already difficult enough, without having to make sure the inner nut doesn't shift as the locking nut is tightened on to it.

Andy

tom osselton · « **Reply #10 on:** November 22, 2012, 05:51:09 PM »

It seems that your only looking at the nut and threads sticking out. Why not make a extension piece as long as you want it and thread the one end as the lock nut then it is just a matter of removing the locking nut and screwing it on to take it's place.

DMIOM · « **Reply #11 on:** November 23, 2012, 03:55:03 AM »

Quote from: tom osselton on November 22, 2012, 05:51:09 PM

It seems that your only looking at the nut and threads sticking out. Why not make a extension piece as long as you want it and thread the one end as the lock nut then it is just a matter of removing the locking nut and screwing it on to take it's place.

And, if you follow Tom's suggestion, make the extension piece out of thicker-walled stock so its thick enough to take three suitable tapped holes at 120 degrees so you can also use it as a spider to hold longer bar stock as well? (like a gun lathe)

Dave

DICKEYBIRD · « **Reply #12 on:** November 23, 2012, 10:34:07 AM »

Hi Peter, here's a link to the stop I made for my old Compact 8 clone. Maybe something in it that may help you in your project??

http://bbs.homeshopmachinist.net/threads/55107-Made-a-work-stop-for-my-lathe?highlight=COLLET+STOP

rotorhead · « **Reply #13 on:** November 23, 2012, 05:09:50 PM »

Hi Folks,

PeterE, your idea for a direct dividing attachment for the spindle, reminded me of how I got around that problem on my Master.

I wanted to make some more dividing plates for the miller, so I went this route...

Pics are fairly explanatory, the first was totally direct, the second was a bit more involved to get other combinations..

PekkaNF · « **Reply #14 on:** November 24, 2012, 03:07:38 PM »

That rotab application is so clever it hurts me!

Could have used something like that VERY many times.

THANK YOU!

Pekka

PeterE · « **Reply #15 on:** November 25, 2012, 04:07:08 PM »

Hi again,

Tiling done and now on the finishing of the walls. Ran out of silicone caulking (required by regulations) to fill the corner joints of the walls and around any pipe that comes out of the wall. All looking good so far.

Then looked into this thread and got even more food for thought

Andy, good to know that the lock nut is not hardened, then I presume mine isn´t either as My lathe is a SIEG C3. (Have to make that change from single row ball bearings to taper rollers. Most people I have read info from says that this is the way to go. It´s on my To-Do-list.)

Tom, the nut and how much of the spindle is sticking out is to me the first important matter to decide on before continuing the idea I think. Then what comes in the other end of the thing I make is the following step. Your suggestion is very close to how Mike Cox solved it on his machine ...
http://mikesworkshop.weebly.com/spindle-extension.html
... where he also used the extension as the second lock nut. What feels good with the solution from Andy is that I am not "forced" to use the extension piece as a lock nut, something I think will make the addition more versatile.

DMIOM, Your idea with the spider for long bars is already on the list, the only thing is how to include it in the final solution

. It is one of the uses that makes me investigate the different possibilities available.

Dickeybird (Milton), Yes very useful info there on your solution

. Just got to ask; Are you threading the main block onto the end of the spindle?

rotorhead (Chris), Very clever setups I must say. They also seem quite easy to attach. Are you securing the division crank in the first picture using an expansion inside the spindle tube?

Well, I think the ideas are kind of forming themselves now. A possible solution will most probably be based on an extension piece threaded onto the rear end of the spindle. The two lock nuts will become one to give room for that, and the single lock nut will most probably get at least two set screws with copper pads (GHT style) to really make sure the position is locked good.

The extension piece will get a threaded end as well, onto which I can either put a 60 tooth gear for division using my simple setup, or a "nut" with three M6 socket head scerws making a spider for long stuff (or maybe even both at the same time?). The extension piece will be made long enough to protrude through the gear cover so as to make swarf coming through the spindle drop on the outside instead of inside among the gears.

Have to draw this to see where it goes, will be back!

Thank you so much for ideas and comments.

BR

/Peter

rotorhead · « **Reply #16 on:** November 25, 2012, 04:48:55 PM »

I received a notice whilst prepping this reply, the crank is located by a rusty looking tapered caphead screw, directly into the spindle protruding out of the rear, it's a handy place for all manner of attachments.

I also made up bar centering sleeves, an adjustable screw type chuck, drawbar guide and a backstop, I'm afraid my backstop was very limiting to length

I actually posted the pics wrong way around, I used the rotab to help make the division plate for the end of the spindle.

I was making some 125 div micrometer dials for my MkI Clarkson, the MkII comes with that refinement.

The bracket was also used to help get the number stamping in line, on the dial seen doing on the lathe.

Lastly, apologies for semi-hijacking this thread.

PeterE · « **Reply #17 on:** November 26, 2012, 04:35:43 PM »

Hi Chris,

No need to apologize, this kind of diversions is really helpful and broadens the subject very helpfully.

I think your solutions are great and combining several functions using the same set of attachments gives a great versatility to the lathe.

BR

/Peter

rotorhead · « **Reply #18 on:** November 27, 2012, 03:20:50 PM »

Hi Peter,

Thank you for your positive comments, I do try to design whatever tool/jig I'm trying to make, to be of multiple use, as resources and materials are limited.

I also find that most of what I originally intended to make, usually incurs the making of several other bits of equipment, I call them my 10 to 1 jobs.

Do the rest of you usually find this?

Chris

DICKEYBIRD · « **Reply #19 on:** December 25, 2012, 08:51:22 AM »

Quote from: PeterE on November 25, 2012, 04:07:08 PM

Dickeybird (Milton), Yes very useful info there on your solution . Just got to ask; Are you threading the main block onto the end of the spindle?

Sorry 'bout the slow response Peter; I somehow missed your question. You're probably finished with yours by now but I'll post this anyway.

Yes, I started with an extra preload spanner nut I purchased from Grizzly for a 9x20 lathe on the gamble it would fit the threads on my Compact 8 clone. It did fit perfectly but a little bit of bluing & scraping was required to get a good mate with the existing nut.

My lathe spindle had about the same number of threads as yours and it doesn't take many threads to hold it very solidly as long as the mating surfaces fit well. Once I had the nut fitting well, I mounted a chunk of aluminum to it with 3 allen head screws and loctite and went from there. I use it often and it works very well. Should'a made one long ago!

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Author Topic: Headstock Spindle Back Stop (Read 15048 times)