Help Clarke CL430 Lathe feed coupling

[daz996Participant @daz996]

Hi guys done something stupid I’m always wanted a lathe and bit the bullet and bought a little Clarke cl430 lathe 5 months ago. Not used it yet but thought I’d oil up the ways etc as it’s sitting in the garage and slid the tail stock back and turned it on so I could activate the power feed to oil under the tool post area, but unfortunately because I’d slid the tail stock right back it stopped the power feed rod from rotating and shattered the power feed coupling 🙁I’ve  contacted Clarke and no parts are available.

Im sure I’m not the 1st to do this does anyone make this part or know of anywhere I could purchase the part, upset with self for making such a silly mistake,any help would appreciate. Sorry new to the group I can’t see how to upload pics

[daz996Participant @daz996]

[BazyleParticipant @bazyle]

Not to worry. It is round ie can be made on a lathe, and you’ve got a lathe. It isn’t essential for actual use all the time so you can still make on on your lathe.
You can perhaps make one more easily out of a plastic like Delrin or Tufnol. You might even be able to get someone in your ME club to 3D print one.

[DiogenesParticipant @diogenes]

How does the part transmit the drive ? – looks like it has a hex-shaped recess?

[JasonBModerator @jasonb]

I thought I could see a recess Hex  too, can you take a photo of the mating part and are there any balls or springs involved making it a slipper clutch rather than a direct drive coupling.

[Howard LewisParticipant @howardlewis46836]

The CL430 (and the CL500M) was discontinued some time ago.

The original couplings might be sinters, so more liable to shatter,than plain steel.

This feature might act as a fail safe, to protect other parts in the power train.

LONG shots

Chester sell the Model B which looks iike the Clarke CL500M (The lathe with the milling attachment)

Although the Model B may be the higher centre height version, there is the possibility that it might use use the same coupling.

They might have spares.

Warco used to sell similar machines. But discontinued them a long time ago.  But might be worth asking if they have any as old stock.

The part that you seem to need is listed in the Clarke Manual as No. 25 in the Gear Train section, Part no HT300030025

If you have not got the manual, and parts list, send me a PM with your E mail address, and I’ll E mail you copies of the CL500M one.

If the coupling has hexagonal recesses, would it be possible to fabricate a coupling by shortening and brazing/welding together two capscrews with the appropriate size hexagon?

As a last desperate resort, you could turn up a thick walled sleeve (Preferably with two two counterbores with a blank section in between, for axial location) which is a tight fit over the corners of the hexagon, then drill and tap holes at 120 or 60 degree spacing for grubscrews to bear on the flats.

Ideally the sleeve should wall be thick enough to allow 1 diameter thread engagement for the grubscrews.

Another “Go for broke” method, might be to buy two good quality single hexagon sockets (Probably won’t  matter whether 1/2 or 3/8 drive)  shorten both, and turn a deep chamfer on the new ends. Then weld the two together, to make the replacement coupling.

The chamfer will aid weld penetration, but clamp in a piece of angle iron to maintain alignment.

If the weld stands proud and liable to foul anything, you can always turn it down to clear.

Obviously the feed will have to be manual!

Probably the alignment of the hexagons may not be vital, although ideally keep in line, just in case.

Howard

[JasonBModerator @jasonb]

Howard, I think it is actually part 18 “Hex socket Sliding Bush” The leadscrew has a keyway and key so no hex for that part to engage with.

Part 15 probably has the male hex and a rack cut into the bottom that is then moved by the lever to engage 15 into 18.

Part 18 also needs the keyway that can be seen in the photo a swell as the hex.

parts pics and list

[Howard LewisParticipant @howardlewis46836]

Thanks Jason

So part No HT300030018 then.

The key way is probably the stress raiser that led to the breakage.

If available, might be worth buying in an extra couple of spares,  in case of problems in the future.

If  no spares obtainable, in some ways a key way might make manufacturing a replacement easier, in that it could be a circular sleeve with a key way filed in, and a key made  to fit each end.

Howard

[Robert Atkinson 2Participant @robertatkinson2]

Assuming the OP can’t machine a female hex modifying a socket or using the end of a box spanner (remember those?) with a bush insert might be the best approach for making a replacement.
A box spanner would be easier to machine as they are not hardened.

Robert.

[Howard Lewis]

On Howard Lewis Said:

 

If  no spares obtainable, in some ways a key way might make manufacturing a replacement easier, in that it could be a circular sleeve with a key way filed in, and a key made  to fit each end.

It still needs the hex at one end unless other parts are modified.

The hex acts as a basic dog clutch to engage and disengage the feed to the lead screw

If the short shaft No23 is not too hard I’d be tempted to do away with one of the keyways and drill through the mating part and that shaft for a brass shear pin and hope that lets go the next time there is a crash

 

EDIT I think it is the broken part that moves not part 15 as I said earlier. The lever engaging in the circular groove

[Martin of WickParticipant @martinofwick]

If you cant find a spare,  to get by 3d print in quality PLA or PETG, followed by thermal treatment from 45 up to 85C for a few hours would be my way. Once the design is proved you can make a few replacements for future ‘events’!

If PLA proves inadequate, once prototyped there is the option of getting a company using laser sintered printing to produce the part in nylon12 (maybe they have something even stronger now). They usually have minimum charge so you may have to have a few extra copies to get your moneys-worth.

I went down this route for a bevel gear(s) in an old Bernina sewing machine. The parts produced by SLD were better than the originals and cost about £60 + postage for 4 units, not too bad for an unobtanium item ( this was a couple of years ago).

[John HinkleyParticipant @johnhinkley26699]

I would endorse Bazyle and Martin’s suggestion of 3D printing, but I would use PLA-CF filament.  It has a carbon fibre element to give added strength.  I have printed a number of components for my lathe using this material, and it seems to be of adequate specification for what I’m using it (a servo motor mount and apron gears).  As it appears that the coupling is probably a sacrificial part, a tough, plastic component may well be sufficient, if not exactly ideal for the job.  It will, at the very least, allow a more substantial item in metal to be made in the interim, should it turn out to be inadequate for the job.

John

 

[Howard LewisParticipant @howardlewis46836]

If the OP cannot obtain a spare, ideally, someone with the facilities and skill, needs to see the parts, so that a replacement can be made.

Where are you located, OP?

Maybe there is somebody close who mcan help

Howard

[BazyleParticipant @bazyle]

Perhaps if we wait a while there will be someone with this lathe who can give us a picture of an unworn and not broken one, with some dimensions.

[daz996Participant @daz996]

[daz996Participant @daz996]

[daz996Participant @daz996]

Sorry guys all notifications was going in my junk folder, I was thinking of buying a 14mm impact(soft)3/8 socket and trying to bore out the centre and file in a keyway

[Speedy Builder5Participant @speedybuilder5]

I guess it was made of cast iron so that it would shatter in situations like you had. If you make it out of steel, it may be too strong and break something else in the headstock drive ??

[daz996Participant @daz996]

Looks like cast iron but the funny thing is on dismantling I found a pin in the feed system that’s about 3mm I would of thought that would of sheared first unless this was already damaged or the pin has been replaced for something stronger?

[bernard towersParticipant @bernardtowers37738]

Pin is likely to be from too hard a material and your hex bit is almost certainly a sintered product which when broken looks like cast.

[Robert Atkinson 2Participant @robertatkinson2]

See my comment on using a cut of box spanner for the hex part. You can then turn up the round piece. The hex cn be pinned, screwed or welded into place but I would bond it with epoxy os if a close fit loctite retainer. Thi is an additional weak point.
Another advantage of a box spanner is if the Hex is non-standard the size can be “adjusted” easily.

Robert.

[JasonBModerator @jasonb]

You would need to choose your box spanner carefully. If slipping it over a spigot then you will need it to have a sufficient bore to clear the keyway and still leave some meat.

Butt joint and silver solder may be the better option in which case you could squash your own hex ring over the 14mm hex mating part

[John HinkleyParticipant @johnhinkley26699]

Daz996,

Is this the sort of arrangement it should look like?

 

I’ve had to make some assumptions for a few dimensions, e.g. size of keyway, hex and hex depth and the dimensions of the groove.  I’d be happy to print one in PLA-CF for you to try, if you’d like me to, I’d just need confirmation of the missing dimensions and your address (by PM).  Permissible tolerances on dimensions wouldn’t go amiss, either, as the PLA tends to shrink diameters very slightly, although I’ve found that with sufficient wall thickness, it will tolerate a light skim.

I’m assuming, also, that you are in the UK, to judge from your electrical wall sockets.

John

Edited to adjust picture size to fit.

[daz996Participant @daz996]

@ John Hinkley, yes that’s what it looks like, I’m got several leads to chase up this week but I’ve got a funny feeling I’ll be taking you up on that offer, thank you

[John HinkleyParticipant @johnhinkley26699]

OK.  Good luck with your alternative sources.  In the meantime, I’ll await your owl.

John

 

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