Disassmelbing a keyless Rohm chuck

[Nitai LeviParticipant @nitailevi73768]

[Nitai LeviParticipant @nitailevi73768]

Hi

Any suggestions on disassembling a keyless Rohm chuck (Spiro model)?

I looked at some web pages and watched a few videos and they all start by removing the thick back washer/collar, and none are specific to the Rohm Spiro. This Rohm chuck doesn't have a washer/collar. The holes are just blind holes, no screws, just one solid piece along with the shank taper.

I found this cut out view https://www.roehm.biz/en/products/drill-chucks/spiro-series/
It looks like the back part and the part above it are both one solid piece, so I'm not exactly sure how they get the bearing balls in there when assembling. there must be a "trick"

I only want to clean it and re-grease it, so removing just the top "cap" won't help. It's a bit resistant from what definitely feels like thick and/or slightly dry grease. Long story not-that-shot… It's new, at first it had a couple of very tight spots. I returned it and they oiled it. The hard spots were fixed and it's very smooth and even now, but a bit too resistant. I can still return it, but decided to try to fix it since it's a lot of hassle and there isn't really a good alternative, so would like to keep it in returnable condition after reassembling. FWIW I don't have a press and can't really go to the hassle of making tools to disassemble it if that's necessary (if it comes to that I'll just keep it the way it is or return it).

Thank you

Edited By Nitai Levi on 13/04/2023 10:40:34

[JohnFParticipant @johnf59703]

Since you say the chuck is new I would recommend you return it to the supplier or at least speak to them !

However if you do wish to disassemble it looking at the picture on your link they appear to be similar to the Albrecht design thus the rear body and the from cone are screwed together so you need to make suitable tooling to grip the parts without damage and unscrew these first then it will probably become apparent how to remove other components.

I do have a disassembly instruction for Albrecht if you PM me with your email I will be happy to share.

John

[Mike HurleyParticipant @mikehurley60381]

Surely if its new and a very good make, any 'resistance' (I'd just call that 'newness' ) will wear off after a little use. Taking it apart etc will surely do more harm than good. If you do break it down but still not satisfied with operation the people you bought it from are perfectly within their rights to refuse a replacement / refund as you have voided any standard guarantee.

So you could end up worse off!

 

edited for rogue smiley

Edited By Mike Hurley on 13/04/2023 10:47:10

[Michael GilliganParticipant @michaelgilligan61133]

Watching the rather impressive [on your linked page] video frame-by-frame might show the moment when the robot inserts the balls.

MichaelG.

.

**LINK**

https://www.roehm.biz/en/products/drill-chucks/spiro-series/

[Nitai LeviParticipant @nitailevi73768]

Thank you.

JohnF thanks I'll send you a PM.

Thanks Michal, I didn't notice the video but watched it now. If the entire video is for the chuck shown at the end, it's a very different model. I think (not sure) the Spiro is the only model with the collar not being a collar and it's one solid piece.

Yes it is new and I'm considering returning it. As I wrote, it came with the tight spots and I returned it. They (the dealer along with Rohm themselves supposedly) decided the issue is probably dry grease from sitting at their warehouse for a while. They oiled it and worked and it did solve the problem.They gave it back to me and said I can check and return it if I want.

It is resistant and I was trying to find out if it is more resistant than it should be, but got contradicting opinions. In comparison with other similar chucks it does feel to me that it's more resistant than it should be. It is smooth and even so doesn't feel like a burr, warp, or anything like that. It feels exactly like too thick and/or dry (but evenly distributed) grease.

Their sales person is only here about once a month and scheduling is tricky, so returning or replacing is a bit of a hassle. If I can clean and re-grease it while it keeping it in returable condition I'd like to do this. I'm 99% sure that will solve the issue.

I bought a very specific size that isn't available from other makers (very small to take less space and use for very small drills). If I return it I will need to wait until they order a new one and if it ends up the same…
I thought of returning it and getting an Albrecht, but that's a special order and costs more than twice the Rohm chuck, which was already a bit more than I was hoping…

Thanks again

[MacolmParticipant @macolm]

Like Albrecht chucks, the main outer section is in two halves, threaded together (see the link from MichaelG). It seems a point of honour for the join to be made almost totally invisible. The two halves can be unscrewed, but are very firmly tightened. If you do not wish to mangle the diameters, you need to make well fitting tooling to grip the each section. One way is to make closely sized aluminium blocks which fit round after being sawed into halves, used to clamp one section in a vice, and the other section with say vice grips. If you have curved jaw vicegrips then first wrapping a piece of aluminium sheet may allow them to grip without damage.

 

But the classic tradesman`s way is a Stilson and cold chisels.

 

PS Rohm chucks tend to start of very tight, but after several months use become smooth operating. In my experience they are considerably better than the limits Rohm specify for concentricity.

Edited By Macolm on 13/04/2023 11:37:12

[DC31kParticipant @dc31k]

Posted by Macolm on 13/04/2023 11:33:22:

One way is to make closely sized aluminium blocks which fit round after being sawed into halves,

An alternative way is not to saw them in half, but to put just a single slit in the perimeter for a clamping bolt.

Edited By DC31k on 13/04/2023 12:13:26

[MacolmParticipant @macolm]

Agreed a single slit togetther with a precise diameter works very well to grip a similarly accurate diameter. The problem with keyless chucks is you need to clamp either on the knurled diameter, or to assemble the grip on a smaller diameter past the maximum one. In both cases, two halves also allow best distribution of the clamping force, eg when clamped in a vice.

Another option is a chain wrench such as the Visegrip type, but this still needs something intermediate such as aluminium sheet to avoid marking the chuck.

 

You can see how well the join is disguised!

 

 

Edited By Macolm on 13/04/2023 15:23:41

[Nitai LeviParticipant @nitailevi73768]

Posted by Macolm on 13/04/2023 11:33:22:

Like Albrecht chucks, the main outer section is in two halves, threaded together (see the link from MichaelG). It seems a point of honour for the join to be made almost totally invisible.

Thank you for the suggestions. That link is the same as the link in my original post. I guess it's possible they don't show all the parts and the way it's divided there. Based on that drawing and looking at the chuck, it is not almost totally invisible, it is completely invisible. Using this Albrecht drawing for the terms, on the Rohm Spiro it looks like the collar and the body are one solid part. At least I can't see anything suggesting that they are not, which of course doesn't mean they necessarily are.

Though even if the collar was separate, the part marked 2 in the Rohm drawing can't be one piece or else it would have been impossible to assemble with the bearing balls. Removing the collar, if it was possible, wouldn't help with that. Referring to the jaw end as North, the Albrecht seems to have the balls captured between North and South, and the Body would come out from the North side once the Collar is off. On the Rohm it looks like the balls are captured between East and West channels.

In the photos you posted it shows the Hood and Body connection, which as nice as it is on the Rohm too, is clearly separate, and clearly shows that in the Rohm drawing. Once this is removed, unless something is missing in the drawing and invisible to me looking at the chuck, the balls are still "blindly" captured between the parts marked 1 and 2.

I'll also add that I'm even more sure the issue is the grease since it has this feel of trying to spring back slightly at the end of the turn. Meaning if I stop at a certain point it is slightly easier to turn it a little the other way than to continue in the same direction, which I imagine comes from the grease springiness and gripping the walls around it.

Edited By Nitai Levi on 13/04/2023 17:51:36

Edited By Nitai Levi on 13/04/2023 17:52:21

Edited By Nitai Levi on 13/04/2023 18:11:17

[Nitai LeviParticipant @nitailevi73768]

Just adding, on another forum someone suggested that the Rohm drawing is correct, the parts marked 1 and 2 are each really a solid piece, but the blind hole is not a blind hole, but a hole for inserting the bearing balls, with a plate pressed into it. It does look like that in the drawing, though on the chuck itself it does look like a blind hole, and in addition the bluing also looks identical.

Of course in spite of that they might be right. it could be a pressed plate, and in that case it does solve the entire mystery, but unfortunately also means destroying the plate is probably the only way to disassemble it. This is not an option since it has to stay in like-new returnable condition.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Nitai Levi on 13/04/2023 17:48:38:

Posted by Macolm on 13/04/2023 11:33:22:

Like Albrecht chucks, the main outer section is in two halves, threaded together (see the link from MichaelG). It seems a point of honour for the join to be made almost totally invisible.

Thank you for the suggestions. That link is the same as the link in my original post. […]

.

Yes, of course it is … I simply made it clickable for the convenience of others, when I was referring to the video.

MichaelG.

[Swarf MakerParticipant @swarfmaker85383]

If stiff grease is the issue, I suggest that you gently warm the chuck with a heat gun (hair dryer?). I doubt that any grease is so old that the lighter elements have all evaporated and so the warmth should lower the viscosity and you will feel the difference – thus proving your theory. In extremis, more prolonged heating and the old lubricant will probably run out, allowing you to introduce fresh.

[MacolmParticipant @macolm]

The normal Albrecht chuck can be completely dismantled after unscrewing the hood piece and removing the collar. You are well advised to do this over a tray to catch the loose balls. As far as can be deduced, the Rohm chucks indeed have balls introduced via a fill hole which is plugged. That being the case, removing them all to get the parts separated might be difficult.

Anyway, I think it is quite possible that the plain bearing surfaces between the shell and body might have tight spots when new. Once "run in", there is no appreciable slack,so it must be a very close fit.

Incidentally, by dismantling either make far enough to unscrew the spindle, you get enough access to press out a taper mounted arbor.

[Nitai LeviParticipant @nitailevi73768]

Posted by Michael Gilligan on 13/04/2023 18:18:50:

Posted by Nitai Levi on 13/04/2023 17:48:38:

Posted by Macolm on 13/04/2023 11:33:22:

Like Albrecht chucks, the main outer section is in two halves, threaded together (see the link from MichaelG). It seems a point of honour for the join to be made almost totally invisible.

Thank you for the suggestions. That link is the same as the link in my original post. […]

.

Yes, of course it is … I simply made it clickable for the convenience of others, when I was referring to the video.

MichaelG.

Yes, it's just that it was suggested to me to see the drawing that I posted, so I wanted to clarify that I already saw it and that is what I'm basing the problem of it being "one solid piece".

[Nitai LeviParticipant @nitailevi73768]

OK thank you everyone. There are quite a few pages and videos showing how to disassemble an Albrecht (or Albrecht style) drill chuck and this was clear before I posted. All signs suggest the Rohm is different, and I suspect the plugged side hole option is likely. Unfortunately if that's the case disassembling is not an option as it seems it's not possible to remove the plate without damaging it. I went ahead and emailed Rohm to see what they say. I thought throughout the forums someone might already have experience disassemble this exact type of chuck, but (to my surprise at least) no one has so far.

[old martParticipant @oldmart]

The thin plate could be removed and the balls shaken out and when being reassembled a new plate made up dished like a core plug and pressed flat. I would be reluctant to take a new chuck apart as it will likely run in with use as already mentioned. The nose end could be unscrewed from the middle section (pn.2) to make it easy to wash the jaw assembly, but it is unclear whether the jaws can be completely removed with the balls still in place. I believe the Albrecht instructions mention not lubricating the centre threads, that might also be the case with Rohm.

[Nitai LeviParticipant @nitailevi73768]

Posted by old mart on 14/04/2023 17:58:51:

it is unclear whether the jaws can be completely removed with the balls still in place

Yes not completely clear, but possibly the jaws probably can be slid out to the side once the hood/cap is removed. I don't really know where the grease is that is causing the resistance, but probably not from the jaw area (I'm guessing either the shell over the body, or maybe the bearing balls channel).

I'm waiting for a reply from Rohm. If it's a pressed plate I'll just decide whether to return or keep it. If it's something else I will try to clean and re-grease it.

Edited By Nitai Levi on 16/04/2023 05:16:22

[MacolmParticipant @macolm]

Can I suggest you try a small amount of penetrating oil, applied at the gap between parts 1 and 2 (if not already tried). This has more chance of getting to any congealed grease in the area of the sleeve bearing.

[Nitai LeviParticipant @nitailevi73768]

First I have to say I got many more replies trying to help here than the other forums I tried, so thanks very much.

I normally wouldn't want to oil it since it might be visible (I understand some drill chucks are supposed to not be oiled)… but the store told me they oiled it a little, and I could see a bit of oil coming out of it already, so I oiled it a little more and also heated it again. Their oiling improved it (it removed it hard spots) and first time I heated it it did solve the problem temporarily, but it reverted back once it cooled.

After my oiling it is now fine after two days. I will keep using it for a couple of weeks and see that it doesn't get back to how it was. I'm still not sure but I think it's good enough. Overall the feel is a little smooth and just slightly more resistant than my Rohm keyed chuck. There are a couple of spots that if I turn it pretty slowly and really try to notice, I can feel something… hard to describe what… the tiniest friction.

I also checked run out and not sure about it yet. I can only really check it right now on my mill, which is a very basic mill. Mill spindle is 0.015mm run out. Depending on what I hold (I tried a couple of twist drills and and a couple of center drills) it's 0.06mm to 0.07mm. The keyed chuck on the same spindle checked the same way is 0.06mm to 0.08mm. At least part of it could be the shank and I don't really have a way to check that.

I actually intend to use it 99% of the time on the lathe, drill very small holes in plastic (0.5mm to 0.9mm), got it specifically for that. I could check with a short puppitast in the head and chuck in the tail, but that probably has too many things affecting it to narrow the chuck itself. Leaning towards keeping it.

Thanks again

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