Member postings for Steve Crow

No please, all suggestions are welcome. I couldn't have got this far without the help from various posters and I'm very grateful.

Before I even start getting in materials, I want to make sure I've got a good, sound design that can be replicated and scaled.

I'm going to have a few days now away from the "drawing board" as I've got other workshop projects I've been neglecting!

Cheers

Steve

Forgot to mention a third reason for the lock nut arrangment.

I can use a spanner on the rear inner lock nut to hold the spindle for undoing the collet nut. And the outer one for tightening of course.

Steve

My reasoning behind the locking arrangment is twofold.

Firstly, ease of assembly. The spindle and bearings can all be assembled and locked up then loaded into the housing from the front. Then the pulley and locknut can be nipped up.

Secondly, the pulley can be changed for other sizes without disturbing the spindle.

I need to make the rear inner nut a bit thicker so I can access the flats with a spanner. This will push back the pulley by a couple of mil.

Steve

Here is the complete shorter spindle for my lathe cross slide.-

The pulley is an arbitrary diameter for now but will use a 3mm drive belt. I forgot to dimension it but the pulley inner/boss outer diameter is 8mm.

The longer spindle will be acting as a quill in a sensitive drill so I'm going to devise an isolated pulley system. I've not even started on the design of all that, I wanted to make sure I could make an effective spindle first.

Steve

Hi Clive, that Leinen system sounds simple and elegant but I should imagine it's fiendishly difficult to match the lenghts of the tube for an optimal result.

I have seen that "remote pulley" system on a few machines. I was thinking of useing something similar for my longer spindle.

Steve

Two more drawings. The first is the nose lock nut suggested by Kiwi Bloke.

The second one has a wave washer in the nose. It's shown loaded on the drawing dimension wise.

This one looks kind of complicated. I'm sure it can be simplified.

Steve

I may well be incorporating the rear nut into the pulley yet. That way won't the torque keep the nut locked?

Once I'm happy with the rest of the spindle design, I'm going to look at the drive etc.

I like the nose nut lock suggestion and will do a drawing but I've also found a wave washer that fits so will draw one for that as well.

I would rather not use loctite on this. No objection to it, I use it all the time, bu I'd rather not on this spindle.

Steve

This time I've drawn the shorter version, it's easier to see the whole thing. Bearings are 3.23 x diameter apart.

I've taken on board suggestions for simplifying the spacer tube and the dimensions have been adjusted so all abutments are to the SKF spec. for those particular bearings.

There were also dimensions (0.2mm) for the fillet radius for abutments. I have inserts with that tip radius so that should work.

Not sure how to lock the adustment nut. I can't find any wavy washers that fit such narrow confines. Suggestions welcome.

Steve

Edited By Steve Crow on 24/07/2023 15:09:38

Thank you for all the input.

I will do some revised drawings with a simpler spacer. When it comes to abutment sizes etc. I've found this information for the bearings i intend to use so I can incorporate it into my drawings (which are to scale, by the way)

I know what you mean about the stiffness. I had a look at the SKF link. This spindle has bearing spacing of 6x diameter which is nearly twice recommended.

I need the length as this particular one will need to be able to slide at least 20mm in a 50mm long bush/sleeve. It will only be used in the vertical position for light drilling so I think I'll get away with it.

I intend to make a shorter one as well for my lathe cross slide. That one will have to do some light milling so will be stiffer. I will watch your linked video later.

Steve

I'm really appreciating all this advice and I've tried to work in the suggestions for these drawings-

The second one can be assembled first and has a beefier spacer. Things are getting simpler!

All comments welcome.

Steve

Thanks for alll the suggestions. I'm all for simplifying things.

The tubular spacer sounds a good idea, I will do another drawing.

Reducing the overhang as John MC also sound good but I'll only lose 4mm that way. Still worth doing.

The spacer between the nose bearings was an earlier suggeston from Kiwi Bloke though maybe I misinterpreted it.

Regarding the internal circlip at the nose, I thought you would need a degree of adjustment here to clamp the outer race against the housing shoulder?

As for suggestions that I bore right through 14.5mm so I can fully assemble the spindle first, I don't understand how I would secure and locate the rear bearing?

Steve

Edited By Steve Crow on 23/07/2023 11:25:24

My error the, thread should be M17 x 0.5.

The odd sizes were just meant to show clearance on the thread crest. Effectively, they'll be M7 and M8.

I'm only planning to buy in the bearings - I'd like to make all the other parts myself.

Critical comment time!

Preliminary drawings for my spindle with a few critical dimensions. Front end first -

The rear -

And for wht it's worthh, the whole thing -

The colours are for clarity, they are not meant to represent materials.

Steve

I think I ought to clarify - I'm looking to use the spindle for drilling sub 2mm holes and very light milling, 1mm or less with shallow cuts. Rev range will be 5k to 15k rpm.

Regarding the spindle book, I'm basing my design on the basic spindle in Ch3. I am no expert but the other designs didn't seem quite right, especially the "loctite" ones. Thank you Kiwi Bloke for for your observations. I like the idea of a spacer between inner races - I'll incorporate it into my design.

I'm sure I remember a thread from a few years back where flaws in the spindle book were pointed out but I can't seem to find it.

I will post my drawings when I've finished them for comment.

Cheers

Steve

I want to make a small (20mm housing dia.) cartridge spindle for ER8 collets.

I've got the Harprit Sandhu book and there are a few that I think I can miniaturise. I like the designs with 2 bearings up front.

My question is, would there be much or any advantage to having 3 bearings up front? How about 2 at the back?

I have to use quite puny (8mm x 14mm x 4mm) bearings due to space constraints so i'm hoping that stacking them up could help.

Cheers

Steve

Sorry Geoff I've tried to send you a pm but I just can't work out how to do it!

I've received and replied to them before so if you send one to me, I can get back to you.

Cheers

Steve

I wanted some small steel balls for a capstan handle for a sensitve drill I'm "refreshing".

So I looked on eBay and found a cheap and varied source - body piercing jewellery!

The internally threaded balls are surgical steel (allegedly) and are available from 2mm to 6mm diameter with a M1.2 or M1.5 thread. They also come in black and gold colours. The black ones might be good for scale models of full size machines. No doubt other colours are available - I didn't want to delve too deep.

I used 5mm for this but I've got some 6mm on order for some small locking levers.

And the cost? £3.31 including p&p for a pack of 10.

Steve

I wish to paint the aluminium castings of a very small pillar drill I'm rehabilitating and I really want to keep the outlay to a minimum.

I realise that i will have to splash out on an etch primer (U-Pol Acid 8) but I'm hoping I can use that for other projects as well.

Ideally, I would like to use Paragon paint in machine colour of my choice but a 500ml tin is enough for dozens of castings this size.

It's not so much the cost as the waste that I don't like.

Can anyone suggest an alternative? I can't find any sample size tins that would suit me.

Is Humbrol and the like suitable for a job like this? I will be applying it by brush.

Also, the castings are a bit rough and pitted and I think maybe a high bulid primer over the etch primer might help.

Any thoughts on this or any alternative.

Cheers,

Steve

Have a look at this.

Twice the price of a Cowell's, 4 times more than a Sherline but not a lot more than a 50 year old Swiss equivalent, Schaublin and the like.

I've read posts on American forums from people who've bought and used it and they have nothing but praise.

Thank you Geoff, this is really interesting. I will send you a pm.

I am assuming these were pre-war castings as people might have been otherwise occupied in June 1941.

Also, the drawings have the flat belt "fast and loose" drive, as in one of the earlier posts.

Seeing it's vintage, I'm going to try to give it a sympathetic restoration.

Cheers,

Steve