Rare Earth Magnet in Headstock?

[spenny_b]

Hi there guys,

Signed-up to the forum quite a while ago, but apart from posting a "hello" note I've not really got stuck in to the forum chats...so, first-things-first, Hello (again)!

This last year or so, I finally started to build a dream workshop....well, "dream workshop" within the context of a non-lottery winning lifestyle....which involved adding an extension to my garage, approx doubling the footprint, into which I bought a 1970 vintage Colchester Bantam 1600 Mk1 and a Eliott Progress No1 pillar drill.

The first job after the building was built, insulated, wired, etc was to do a very light cosmetic restoration to both the drill and the lathe. Rubbing back the paint, cleaning up the metalwork and generally making them ready for use. I've deliberately not used the lathe until I could get around to draining the oil in the headstock and gearbox, cleaning it out and refilling with the correct grade (Shell Tellus 27 now translates to Triad 32 ( http://www.morrislubricants.co.uk/scripts/prodview.asp?idcat=80&idProduct=41 ) for any UK based folk Googling for the answer). The next job will be to do the alignment checks, but overall I'm very happy with how everything's turned out, and FINALLY I have my very own lathe....a promise I made to myself 15yrs ago when I lost access to a full model-shop at my old job (I left the job, I wasn't banned from accessing it!)

Lathe as it was delivered...very tired looking, cracked gear cover....




And after many many hours of work, repainted using original Colchester coloured paints.







Last night, I eventually found time to drain the oil....well, the headstock oil, it turns out there was nothing in the gearbox! Headstock oil looked "ok", no idea of the grade that was in there, but looked far more viscous than the Triad 32 I used to refill it with. Worryingly, there was a fair amount of fine metallic particles at the bottom, in the far corners, etc. Spent a good few hours throughly cleaning it out, magnetic stick, cloths and plenty of elbow grease. As this model of lathe was used in schools, colleges, universitites and industry as a learning lathe, I guess somebod has been too enthusiastic in trying to switch gear speeds before the gears have stopped....there's evidence of chewed teeth on the top right hand speed selector. It still works fine, but at some point I'll source a couple of new gears and replace them....hopefully. I have plenty of spare oil, enough to treat last nights refill as a flushing fill, and drain off once it's been around the gears for a short while.

So, the question in the title - has anyone made their own magnetic particle collector that sits inside the headstock? Looking on eBay, rare earth magnets are plentiful in sizes and shape, and very reasonably priced. I'm sure the drain plug isn't magnetic, there wasn't anything stuck to it. Very wary about just getting a 25mm diameter x 20mm magnet and just sticking it at the bottom of the casting; of course it'd be disastrous if the turbulence of the oil flung it up into the gears!...or am I over-thinking it, and that's the way everyone does it?

Alternatively, drill a hole in the access lid on top of the headstock, and make a rod that dangles down between the shafts in the headstock, with a magnet affixed to the end of it. The rod could then be fixed to the underside of the lid (drilled and tapped) and sealed with an o-ring?

Thanks in advance guys, and great to be on-board!

Cheers
Spencer.

 

[pdentrem]

I use a 1" rare earth super magnet stuck on the exterior of the oil filter on my motorcycle. It is still there. This size has a 30# of holding power. Just stick it is the bottom and no worries. I imagine there are vendors in your area with these as well.
http://www.leevalley.com/en/wood/page.aspx?p=32065&cat=1,42363,42348

You could also drill a correct sized hole in the drain plug and place a small magnet there. There are sump plugs for the automotive industry made this way, for engine, transmission and differential. I sold many of these while working at the auto dealership.
http://www.drainplugmagnets.com/
Pierre

 

[thomas s]

Nice job on the lathe and the new shop looks good

 

[george wilson]

Too bad new lathes can't have nice shaped castings like your tailstock. I wonder these days if they only teach pattern makers to cut square blocks of wood and stick them together.

Nice looking lathe,and I would not worry about a rare Earth magnet coming loose. What I WOULD be concerned about,would be the magnet magnetizing the gears in the headstock,causing chips to stick to them. You know what,I'd leave the magnet OUT!!!!!

Even without any magnets,my milling cutters seem to get magnetized all by themselves until they annoyingly hang onto little chips and steel fuzz. This could prove disastrous to the longevity of your headstock gears. And,what if the bearings got magnetized? How would you de magnetize them?

 

[pdentrem]

I would rather have the magnet in the bottom of the sump than small little bits of steel swimming in the oil.

Hand held deguasser will do the job. Magnaflux will do the same but more expensive!

 

[spenny_b]

Thanks for the input guys....some good points raised!

@pdentrem - Yup, I've got similar drain plugs on my engines, so have seen how effective they can be. Wonder how "magnetizing" a rare earth magnet would be, ie., how close to a gear cluster would it need to get, in order to magnetize the gears/shafts/etc?

If a magnet of this strength was stuck to the bottom of the headstock casing, would that magnetize the casing as well? (never had first hand experience with the strength of these magnets)

You could argue, that notwithstanding the abuse it may have had by clumsy learners, it's been alright since 1970!

Think I'll sleep on it

- - - Updated - - -

Nice job on the lathe and the new shop looks good

Thanks Thomas! Quite pleased how it all came out....trouble is, I now want a mill in there as well, and there simply isn't the room!....well, not until my engine project get completed and the engine gets back into the car.

- - - Updated - - -

Too bad new lathes can't have nice shaped castings like your tailstock. I wonder these days if they only teach pattern makers to cut square blocks of wood and stick them together.

Haha, yes, it's quite a nice classic shaped piece of kit.....just the right size, a fair bit smaller than a Student that I learnt on many years ago. No doubt it'd benefit from a full-on strip down and refurb (I noticed tonight that I already have a small pool from some weeping seals), but it looks to be reasonably well aligned judging by the pieces I've been turning this evening.

Cheers
S

 

[pdentrem]

The magnets are very strong but have a very short working distance. They are highly concentrated field lines.
The normal magnetic field of the Earth will impart a small magnetic charge on anything over a period of time. I wouldn't be too worried about it. Likely all our lathes and mills already have a charge no matter how old they are.
Pierre

 

[middle.road]

A computer guru's method of attaining magnets for the headstock:
Inside a computer's hard disk drive (3.5" or larger) you'll find a pair a very nice strong magnets. Odd shaped but very useful.
I use them all over the shop, I've been salvaging hard drives for their bearings and magnets for years.
Working distance is low. I've placed one at the front and back on the bottom of the birmingham headstock housing where the slopes in the casting are.
Scrounging hard drives is pretty easy.


Do be advised, they are strong, field of about 1 to 1.5 inches. Don't get them near you wallet (debit/credit card mag strips) or mobile phone.
They are usually attached to a backing plate which you can use for mounting screws and such. The yellow shrink-tube one in the lower left
is from an old 5.25 full height disk drive. It is darn near a 1/2" thick and very strong. I put the tubing on it to allow getting chips and filings off of it easier.
I've had luck using solvent or heat to remove the magnet from the mounting plate.


_Dan

 

[hman]

For a magnetic drain plug, I'd suggest the following:

Buy (or fabricate) a brass plug that's the same size as your existing plug. Then select a magnet that's about 1/2 the root diameter of the plug threads, and about 1/4" shorter in length than the plug.

Drill a suitable hole in the plug (note - many brass pipe plugs I've seen and bought recently are already hollow, probably because of the high price of brass). If possible, size the hole for a mild press fit, then press in the magnet. If that's not possible, go for a clearance fit and gently peen the end of the brass over the end of the magnet. A center punch will work for this. Just be careful not to shatter the magnet.

In any case, don't depend on any kind of adhesive to hold the magnet in place!

I don't have a "wet sump" lathe, but I've added magnetic drain plugs to various gear boxes, including my 4x6 bandsaw(s).

 

[spenny_b]

Guys, thanks again for the various ideas....I think I'm erring towards the idea of making a new drain plug so that it's well away from anything it could magnetically induce. I had been thinking about making a brass one and then attaching a magnet to the end using a countersunk screw and using Loctite Threadlock....there are quite a few magnets available that are drilled and countersunk; whether I can get one that's fractionally smaller than the root diameter of the plug thread, is another question....some eBay searching will happen this evening!

Having spent the evening turning last night, getting the gear cluster and headstock nice and hot (keeps my mug of tea nice and hot when it's standing on top!), I can see weeping of oil from a few places like the speed selection levers, so perhaps I'll treat this fill of oil as sacrificial, flushing everything through, then drain it off, remove the plug, fix leaks and then refill with the new plug.

I'll update as soon as I get something done!

Cheers
Spencer.