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I'm trying to source a replacement chainwheel for an old (probably 1980s) Swedish woodworking machine. I've approached the manufacturers in Sweden but they aren't really the same company they were in the 80s/90s so while I wait for a response I thought surely someone on here would have a UK source for this kind of thing. Being a Swedish machine, if it's like others it's likely to be a fairly standard metric dimension part, possibly off the shelf somewhere.
The overall diameter is no more than 45mm (inc. chain), the main body is 17mm diameter, slimming to 15mm. Total depth is 45mm with the chain running on the first 25mm. The chain itself is 18mm links with pins at 14mm centres as best I can measure without disassembly. The whole thing is held on with a small hex bolt. Where can I get such a thing? Someone on here must surely know just the place & any help will be much appreciated.
Lovely phone pic for anyone interested...
You'd need to do some more careful measuring, but this sort of thing is commonly available:
You may need to get a engineering company to machine the bore of a generic part to fit the shaft.
👍 @crogthomas, I'll have a look, thanks.
One typo above, total depth is 25mm chain running on first 15mm. Like you say, more careful measuring needed...
What's the make of machine?
Might be a group somewhere like Facebook possibly.
RS sell a range of them too
https://uk.rs-online.com/web/c/mechanical-power-transmission/roller-chains-accessories/sprockets/
Indeed, you'll need to do a bit of measuring. 14mm is not a common chain pitch.
These are the common sizes:
The part you're looking for will be called a sprocket.
You need to identify the chain from the pitch, internal width and roller diameter. Bear in mind that the chain you've got is likely worn, so the pitch may not measure accurately.
There's a table of standard sized here:
https://www.fbchain.com/knowledge-hub/how-to-quickly-and-easily-identify-roller-chain
Next you will need the number of teeth on the sprocket and details of the hub (bore, fixing method, keyways, etc.).
Armed with that information, you can approach one of the engineering suppliers (e.g. https://www.gearsandsprockets.co.uk/0.5-inch-081-steel-chain-sprockets.html/ ).
You *may* need to pay to get the hub machined to suit your machine.
Sheesh, 1980s = old 😭
Thanks for the advice all. The make is a Luna, nothing much online in Facebook groups that I've seen, only on a couple of dated Swedish forum threads. I'm sure if it was an archaic Wadkin I could ascertain what parts were needed pretty easily.
I've established the chain is 3/8" by 7/32" (god bless imperial).
As for getting the part off... I assumed it'd be straightforward once the machine was split apart and I could get access. Chain off, grub screw (that I thought was holding it on) removed cleanly... But the thing will not budge. I thought it should slide off, but no. Tried a little heat, plusgas, some persuasion... Nothing.
So how do I get it off? There is an unthreaded hole on the opposite side of the grub screw that I'm not sure what it's for, and taking the faceplate off the gearbox doesn't appear to help as the hole in it is only big enough for the axle shaft, not the sprocket to get through. Any thoughts?
Is there any sign of a keyway? If not perhaps the mystery hole has a roll pin in it connecting the sprocket to the shaft. There would normally be something to prevent the sprocket rotating on the shaft. Shrink fit is unlikely but no matter what, you might need a puller to get it off.
Can we have some more pics? Sometimes there are two grubs screws down the same hole - or a roll pin or dowel as mentioned above. You may need a small bearing puller if it's been on a while and corroded.
Can we have some more pics?
Of course you can...
[Edit, or you will if I can upload some]
So that top hole is the non threaded one, directly opposite the threaded one that the grub screw came out of.
Also got my hands on a manual/exploded diagram - bit in question is highlighted...
Little bit more heat and eventually forced it off. Grub screw had been over tightened on but should file back the mess and once I find a suitable replacement that should fit ok I hope. Thanks for the help so far...
Of course you can…
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You've had your money's worth out of that!
Which model of Luna? I know at least two people that have similar looking machines to what i just googled in their workshops.
You’ve had your money’s worth out of that!
😆 - it's probably older than I am. It may have been changed at some point though as it seems there are 11 "teeth" not the 12 specified. Surprisingly still runs the feed passably ok even like that.
@mert, it's an s69 kombi (saw, planer/thicknesser). I suspect there are plenty hanging around in their native environment - good machines. Never seen any over here though.
Ah, just spent a few minutes digging, few small places have *very* limited spares. Most of the bigger places just have a blank page for Luna AB or "contact the manufacturer" banner.
HQ is only about 30 km from me in Alingsås, so there's a good chance that they might well be Luna machines in local garages and workshops.
Have you tried looking for Lindahl & Nermark AB groups on facebook, or the actual company page?
Imho I'd increase the size of that sprocket and it's equivalent sprocket whatever it's driving / or being driven off. They look a little too small to be taking any sort of load. Hence the wear.
I'd also consider changing to a timing belt and pulleys instead of a chain.
With my 'elf n safety hat on - what provision is there for guarding of the chain&sprockets to stop stray clothing or digits going in there?
@mert, thanks. I've contacted Lindahl & Nermark who auto directed me back to Luna. I've emailed but suspect I'll hear nothing useful. If it proves impossible to either find or get a piece made up locally and/or they aren't in touch I'll give them a ring. With the position in the machine there's a fair bit of flexibility in the exact spec (chainline/gearing etc not set in stone) so I'm reasonably hopeful that will be good enough.
A couple of friends moved up that way (Alingsås) from GBG a year or so back so could always get them to pick something up if all else fails and Luna do have some inventory hanging about in some old shed somewhere.
With my ‘elf n safety hat on – what provision is there for guarding of the chain&sprockets to stop stray clothing or digits going in there?
@RustyNissanPrairie as you say, it should be a higher gear (12t) but gearing too high would put the speed too high on the feed which it drives to give good results. The higher speed drive for the cutters is off a belt but this is really just gearing a slowly rotating pair of rollers and seems to work ok.
As for health&safety, when reassembled this sits right in the centre of the machine with roughly 500mm of other components either side, totally enclosed from above so no major worries there.
Even a 12t seems a little small - if you increase the size of both sprockets proportionally the chain path will be smoother whilst keeping the driven roller speed the same. The loading on the sprocket/shaft connection will be the same.
Also have a look at Fenner B-Lok keyless sprockets - they use a mechanical shrink fitting into shafts so you don't need to key broach or drill and tap for grub screws. Go to a good industrial chain&sprocket place - these type of guys for example.
https://www.john-fenwick.co.uk/
A timing belt conversion would be even smoother.
*I've worked on big Weinig moulders/tenors, Wadkin's etc and know that smoothness is king.
TBH I'd join this forum and ask there.
Lots of members renovate older machines so are probably a better source of odd long defunct parts. You might find the bit you think you need, you dont really and one tooth either way is going to make little to no difference.
What diameter is the shaft? (if ~12mm, check whether it's really 12mm or whether it's 1/2")
11T sprocket here - bored to your choice of size, tapped for two grub screw and delivered to your doorstep for ~ £17
https://www.gearsandsprockets.co.uk/06b-steel-chain-sprocket-3-8-11t.html
They list down to 8T sprockets for that chain size
Sorry for the delayed reply, been too busy working. Thanks for all the advice above, it was very helpful. Got it sorted with a more or less straight replacement (just needed boring out to fit) in the end and now all is running smoothly. Lots of good info though for another time, so thanks @dyna-ti, @RustyNissanPrairie and@tillydog
And in case anyone reads this in the distant future, Luna AB in Sweden have just replied, does seem they have some spares but would have to check. As I'm sorted for now I'm not going to ask them to pursue it further, but worth knowing.
TBH I’d join this forum and ask there.
Lots of members renovate older machines so are probably a better source of odd long defunct parts. You might find the bit you think you need, you dont really and one tooth either way is going to make little to no difference.
Careful on there though, there's this guy called Triton, seems harmless enough but a bit of an odd duck...