Surface corrosion on a Rohm prima drill chuck...

I got this for $3...

5/32 - 1/2 (1 -13mm) Rohm Prima l.

It is mechanicälly sound (moves freely and keys tighten/loosen fine), the clamps are pristine, and it has about 0.08mm runout (3 to 4 thou) at 5mm past the clamps, which is basically just my lathe spindle runout amplifîed by length.

It had a heap of rust all over, so much I couldn't read the brand name until I wire brushed it. Otherwise I washed & wd40'd it to get some of the crud out. It is on some weird waisted/flatted straight extension with a 5/8“-16 thread... almost looks like it is a piece of the drill press it fell out of. These chucks cost $200nzd... Apparently. I wouldn't pay close to that for a f..king drill chuck. But still, seems like it is worth taking some amount of care with.

Wondering if I should attempt to get the arbor out, and if anyone has any thoughts about further cleaning/lubing.

I was thinking I would just brush/sand the outsides, blue the knurled bit and maybe the, uh, spinny round key hole bit, spindle oil the gear and gap behind the gear, then turn a sleeve to hold it in my tailstock.

I paid nearly twice that for a new Albrecht.

Your plan seems solid. I'd dismantle it and carefully sand/stone the rough spots smooth. The internals are probably quite hard so this should move quickly without damage to the pieces.

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Schofields said:

I got this for $3...

5/32 - 1/2 (1 -13mm) Rohm Prima l.

It is mechanicälly sound (moves freely and keys tighten/loosen fine), the clamps are pristine, and it has about 0.08mm runout (3 to 4 thou) at 5mm past the clamps, which is basically just my lathe spindle runout amplifîed by length.

It had a heap of rust all over, so much I couldn't read the brand name until I wire brushed it. Otherwise I washed & wd40'd it to get some of the crud out. It is on some weird waisted/flatted straight extension with a 5/8“-16 thread... almost looks like it is a piece of the drill press it fell out of. These chucks cost $200nzd... Apparently. I wouldn't pay close to that for a f..king drill chuck. But still, seems like it is worth taking some amount of care with.

Wondering if I should attempt to get the arbor out, and if anyone has any thoughts about further cleaning/lubing.

I was thinking I would just brush/sand the outsides, blue the knurled bit and maybe the, uh, spinny round key hole bit, spindle oil the gear and gap behind the gear, then turn a sleeve to hold it in my tailstock.

Click to expand...

Boil in caustic soda to get all the crud out, blow with compressed air and eventually keep it in vinegar for a while to get rid of all the rust. Then back in ammonia/bicarbonate solution and compressed air. They don't like being taken apart.

Evaporust, if you can get it, will remove the rust and not etch the metal as a dilute acid (vinegar) will do. Wash off the WD40 with dish soap before using the Evaporust (or vinegar).

After you have soaked in Evaporust, wash with hot water to remove any residual evaporust, then soak a short time in alcohol to help remove any water from cracks, threads, etc. Dry with some heat to evaporate off the alcohol. The last step is to soak in Kroil, a penetrating oil well regarded for its use in stuck ad rusted
parts.

There are 5/8-16 to morse taper adapters.
https://www.walmart.com/ip/Threaded...16-Hardened-Morse-Taper-MT3-Adapter/365780770

Cole2534 said:

I paid nearly twice that for a new Albrecht.

Click to expand...

$6? or $400?

I don't bore rifle barrels or drill through excavator bucket plates so I don't have any need for a high end drill chuck. But coming into possession of a very decent midrange one - I'll take that!

Thanks very much folks.

I *think* I can see why it ended up in the rubbish. The jaws got jammed tight when all the way loosened... Once some more rust was gone, I could make out where someone had gone to town on the top of it with something very hard Nothing soaking in WD40, blasting, soaking, probing with a pipe cleaner... And sticking it in the vice and whacking it with ol' faithful brass whacking-s--t mallet couldn't fix. It was a big hard steel chip that had got into the wrong spot. Not steel from my shop I'm sure, so I guess it was already in there... And had probably worked loose over time while sitting in the corner of the junkyard. Other than that it's cleaning up nice. I don't want to take it apart because it's working fine, aside from feeling rough.

I hadn't thought to soak it in alcohol. Or to soak it in penetrating oil like that... I'm not sure if you can get that stuff here. WD40, CRC 556 or their clones mostly. Don't you find it penetrates back out and gets all over drill shanks? I'll have to go to a gun shop to pick up some cold blue anyway, so I'll see what oils they have.

I haven't come across a rust remover product in NZ that I like enough to buy over just getting a giant bottle of white vinegar, or electrolysis. You can get.... ehhh... Rustoleum? Others are just things like some citric acid with some peroxide in it... They're all far more expensive than vinegar, wire wheels or scotch pads.

The Kroil can seep back out, but I have not found this to be a problem, as the volume in a crevice is very small.

Phosphoric acid is useful in removing rust, and any remaining phosphate helps protect the metal and can act as a primer for paint. The most economical source I have found is gallon containers of a solution for etching concrete. You have to read the label though, as other acids can be used-such as hydrochloric acid, which will promote future rusting

Thanks, I'll see if any of the products are reliably just that. Unfortunately here, often somehow they are able to list only the active ingredient. The supplier I buy bulk bleach off has a phosphoric acid sanitiser... I'll ask if it's pure.

They do sell a product called "Acid X" though - phosphoric acid and sulfuric acid Apparently it's for removing soap deposits. I'm sure it does that... And also for "removing concrete". So I guess it's what you buy if you want to dissolve a building.

Although the chuck is cleaned up now. Just needs a bit more time in some oil I think.

In terms of any acid, if it doesn't react fully into something then the h+ ions will remain acids and will promote further rusting. From what I just read, the advantage of phosphoric acid is that it forms an adherent layer on the steel (from the rust) which passivates it....... It's also not quite as "strong" an acid as HCl or sulfuric, so it won't corrode things as quick. I've always tended to rinse thoroughly and dunk in dilute baking soda solution when using vinegar.

I find I get a black, fairly hard layer from electrolysing rust in washing soda solution........ Dunno what that is.......