Cleaning internal MT’s

[Robin GrahamParticipant @robingraham42208]

I'm trying to restore a lathe whjch has some light powdery rust in both the spindle and tailstock tapers. My instinct is to swab out as much of the powder as I can, then glue some wet'n'dry to a male taper and polish with that, but as I've never done this before I'd be grateful for advice. I don't want to make the problem worse! Would MT reamers be a better option? My gut feeling is not, but I don't have a clue really.

Regards, Rob.

[Robin GrahamParticipant @robingraham42208]

[duncan webster 1Participant @duncanwebster1]

Scotchbrite and paraffin works wonders. Not the stuff they sell for washing up, you can get a more aggresive version, but no idea where from, I scrounged some from a fellow club member

[not done it yetParticipant @notdoneityet]

The spindle is no great problem as long as any centre fitted has no run out. It will revolve with the part it is centred on or could/would have a drawbar to tighten the morse taper drive otherwise. Tha tailstock is a slightly different problem in that it needs to resist turning and be in line with the spindle centre.

Wet and dry have a thickness, so any morse taper will not clean out the full depth but must be good for most of the taper. Remember, too, that these tapers may or may not be hardened. The problems start when swarf has been trapped previously or the surface is badly galled.

So my advice would be to start with the least aggressive methods and progress from there. Testing for contact at each stage is important, to know where the high spots are. If resorting to a reamer, then removal of the absolute minimum of material should be aimed for, I would think.

[BazyleParticipant @bazyle]

Scotchbrite is sold by a few of the usual ME suppliers, ebay, and Halfords in the paint preparation section. It is colour coded for aggression and brown is the strongest a bit like a bit of worn out 600 grit sandpaper. (their website might be more specific) Beware it does drop some of its abrasive as it is used so take the usual precautions for cleanliness.

[HopperParticipant @hopper]

Posted by Robin Graham on 26/06/2016 22:18:14:

…glue some wet'n'dry to a male taper and polish with that, …

I wouldn't do this. Too much chance it will remove metal as well as rust and you will end up with a wonky, oversized taper.

Better by far to proceed as suggested by others to use scotchbrite from the kitchen cut into suitable strips and applied gently by hand using a wooden dowel or maybe a screwdriver to get it down into the taper. Just dont let the screwdriver contact the taper directly and scar it up.

[Brian WoodParticipant @brianwood45127]

Robin,

I would recommend the gentlest of approaches, the first being to use a paraffin wetted rag to clean out the rust deposits to start with. They in themselves are abrasive, so removing them is the first step. Dry the bores off with clear dry rag or workshop paper towel, apply a little engineer's blue on a taper and try the fit.

If you are lucky, that may be all you have to do. The degree of pitting may be light enough to have negligible effect on the grip of the taper. A taper reamer, used by hand, will reshape any raised edges in the bore if necessary without removing significant metal from the bore and a plug of tired Scotchbrite will polish the bore without damaging it.

Avoid any use of wet and dry,

Regards Brian

[MikeParticipant @mike89748]

In the past I've used very fine wet and dry wrapped round a MT reamer and rotated anti-clockwise by hand. Anti-clockwise rotation and VERY light contact means the reamer doesn't cut through the abrasive paper, yet you clean the full length of the taper. Lubricate with thin oil or paraffin. Not saying this procedure is correct, but it has worked for me and helped me restore an Amolco milling attachment stored for 10 years in a damp garage.

[Neil WyattModerator @neilwyatt]

I wouldn't use any abrasive method. That way you are just removing what is left of the good, accurate surface.

I have halfway been amazed at how well most rusty boot-sale MT tapers come up from a soak in a rust remover. Get the barrel off the lathe and stick it hole downwards in a bucket of (insert one of dozens of recommended solutions here).

Spray with a proper corrosion preventing oil as soon as it comes out and you have dried it with paper towels or it will rust again.

Neil

[Robin GrahamParticipant @robingraham42208]

Thanks. I have a tube of 'micrometer blue' but for some reason (stupidity at a guess) I never think of it. I shall pursue the wash/test/minimalist abrasive/test route I think.

Neil – I'm not convinced that chemical rust removal solutions (at least the ones I've tried) leave the parent metal unscathed. Certainly the Liberon product I have at the mo eats steel. It's a balancing act I guess, but I feel a gentle mechanical method is going to be more controlled.

Robin

[Neil WyattModerator @neilwyatt]

Posted by Robin Graham on 27/06/2016 21:54:06:

Thanks. I have a tube of 'micrometer blue' but for some reason (stupidity at a guess) I never think of it. I shall pursue the wash/test/minimalist abrasive/test route I think.

Neil – I'm not convinced that chemical rust removal solutions (at least the ones I've tried) leave the parent metal unscathed. Certainly the Liberon product I have at the mo eats steel. It's a balancing act I guess, but I feel a gentle mechanical method is going to be more controlled.

Robin

That's not my experience at all to be honest, every approach I have ever used removes rust but not virgin steel. Try the Liberon on some spotless steel and see if it really eats it away, or just ththat teh rust was worse than you thought.

[BrianParticipant @brian]

No Connection, Gloster Tooling have Internal Morse Taper wiper on Ebay.

Brian

[dave george 1Participant @davegeorge1]

Why not make a mini electrolysis bath, using a bin,water,washing soda and a battery charger, this did wonders for my rusty bits

[Michael GilliganParticipant @michaelgilligan61133]

Posted by dave george 1 on 28/06/2016 10:54:52:

… this did wonders for my rusty bits

.

Miracle cure for Arthritis

MichaelG.

.

… But seriously; electrolytic rust removal does look useful.

[roy entwistleParticipant @royentwistle24699]

Robin if you have a gunsmith nearby and assuming it's a No 2 morse taper You can get a bronze brush and a bristle brush to be used on a ramrod Used with paraffin they will remove light rust I always use the bristle brush before using any morse tooling

Roy

[roy entwistleParticipant @royentwistle24699]

Robin I should have said get brushes for a 12 bore shotgun

Roy

[MWParticipant @mw27036]

Posted by Michael Gilligan on 28/06/2016 11:04:29:

Posted by dave george 1 on 28/06/2016 10:54:52:

… this did wonders for my rusty bits

.

ooh err missus.

Michael W

[MikeParticipant @mike89748]

Roy and Robin: do go to a proper gunsmith and make sure the brushes are bronze or brass. A lot of brushes from DIY outlets that look like brass are really brass-plated steel.

[Robin GrahamParticipant @robingraham42208]

Thanks for further suggestions. There is a gunsmith's local to me, so I'll don me tweeds and green wellies (it's that sort of place) and enquire after a 12-bore brush.

Brian – I couldn't find the item you refer to on eBay – any chance of a link?

Neil – I left a screwdriver in a beaker of the Liberon stuff after fishing out a part, thinking the screwdriver itself might benefit from a bit of de-rusting . I forgot about it for a week, by which time it had become a screwdriver handle with about an inch of metal protruding… OK, I left it too long, but the stuff most certainly ate more than just the rust. Hence my mistrust of a chemical method!

Regards, Robin

Edited By Robin Graham on 28/06/2016 22:21:30

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