Desperate times and desperate measures…

[UncouthJParticipant @uncouthj]

What am I letting myself in for??

[UncouthJParticipant @uncouthj]

Hi Folks.

I’m currently unable to work on medical grounds. I did my apprenticeship in machining, but strayed into maintenance engineering, to my eternal shame. Anyway, I really miss machining so I’m desperate to set myself up a mini lathe, to have something to do whenever I am able. Unfortunately, times have tolled and the budget is obscenely tight, mainly selling prized possessions to finance it, and even that isn’t half what I’d be looking to spend under any other circumstances. So, that’s the desperate times…

Now, an Amadeal CJ18A has come up that I can afford. Some obvious concerns, but I’m prepared for it to need a bit of work. The chap has upgraded to the metal gears, but says a cover has broken somewhere along the way. He’s covered the area with tape to prevent ingress, and says it doesn’t impede functionality.

I guess my whole post here is to see if anyone in the know might see anything fatally wrong, or perhaps can provide insight into the journey that may lay ahead in the repair? I don’t mind desperate measures, but I’d rather avoid pointless ones…

Cheers
Jay

Here’s a pic of the taped up area, and uncovered pic below.

[JasonBModerator @jasonb]

Looks like the shield has come off the 91p bearing so not too expensive to replace, I'll leave it to others to explain how to replace as unfortunately that bit is not shown on ARC's strip & rebuild guide.

Though if no dirt has got in and it's running OK, I'd get a bit more tape.

[HOWARDTParticipant @howardt]

I is just a swarf shield for the front bearing, but the spinel has to come out to replace it. It is just a plastic shield, easily broken of a little hamfisted when refitting. Better to leave it in place unless you want/need to change the bearings. If you want to proceed you have a cholce on the bearing types, normal balll bearing, angular contact, or taper roller. I stick with normal ball bearings as that is what is fitted as standard and the machine, not this one, does what I want it to do. Plenty of discussion and preferences on here as to bearing type chosen.

[UncouthJParticipant @uncouthj]

Posted by JasonB on 19/11/2020 13:26:25:

Looks like the shield has come off the 91p bearing so not too expensive to replace, I'll leave it to others to explain how to replace as unfortunately that bit is not shown on ARC's strip & rebuild guide.

Though if no dirt has got in and it's running OK, I'd get a bit more tape.

Brilliant, that was my thought also. Thanks for that Jason.

My job this afternoon is downloading every drawing, manual, part number and measurement, I can possibly find on the thing…

[Andy_GParticipant @andy_g]

Posted by Jay Nugent 1 on 19/11/2020 13:46:13:

My job this afternoon is downloading every drawing, manual, part number and measurement, I can possibly find on the thing…

The Arc Euro Trade strip-down guide is very good.

https://www.arceurotrade.co.uk/machineguides/C3-Mini-Lathe-Dismantling-and-Reassembly-Guide.pdf

Your lathe may not be identical, but it is likely to be very, very similar.

[BazyleParticipant @bazyle]

You can have some fun designing and making a metal replacement. Then attachi it with double sided tape until one day when you do decide to strip all and drill holes ot screw it in position through the lugs you so sensibly incormorated into your design.
Bunch of other people would 3D print something.

Worst case is the bearing gets contaminated and damaged eventually but as it is just the layshaft it is not too serious and can just be replaced by a cheap bearing.

[Howard LewisParticipant @howardlewis46836]

Bazlyle beat to me the suggestion to make up a metal cover, large enough to cover the damage. With e chuck removed there may be access to drill and tap some holes for the retaining fasteners.

That would make it look a proper Engineers job!

Howard.

[Ady1Participant @ady1]

a metal plate glued on with a smear of pinkgrip will be fine in 4-6 hours

Lever it off with a screwdriver in 5 years or whenever you need access for maintenance

GL

[old martParticipant @oldmart]

Welcome, Jay, I wouldn't worry too much about it, just make sure the tape is doing its job and get machining.

[mechman48Participant @mechman48]

Try a thin piece of Teflon sheeting, cut a hole close to the diameter of the spindle & the OD of the bearing + plus an extra 10 mm, as near as, split the 'washer' down from the top & fit over the spindle glued in place with hot glue gun or even some silicon sealant, niceley sealed up , job done.

George.

[larry phelan 1Participant @larryphelan1]

Give the dog a bone and let him sleep !

Stick a piece of plastic over it and forget you ever saw it.

[UncouthJParticipant @uncouthj]

Thanks for the feedback guys. I can’t wait to get turning!

[Stuart Smith 5Participant @stuartsmith5]

I have the same CJ18A lathe and replaced the main bearings and plastic gears on mine earlier this year after I stripped one of the plastic gears.

There is a plastic cover over the main spindle bearing held on by screws. This has a cut out at the bottom to clear the bearing for the input shaft. This cover looks ok on your photo.

The tape has been put on to cover the end of the input shaft which on yours has either an open bearing or a sealed bearing with the built in shield missing. Mine has a shielded bearing with no other cover.

Either way, fit either a plastic or metal cover over this as has been suggested.

Stuart

[UncouthJParticipant @uncouthj]

Looking at the assy guide, it looks a much simpler teardown than I expected, so that'll be the first job. Make sure eveythigs as it should be. I'm sure I read or watched an artice on turning new bearing shields recently, as it happens.

I may just grab a complete set of bearings etc jic.

Here's to hoping that the biggest headache I'm in for is the 400mile round trip to collect it.

…cue canned laughter… 😉

J

Edited By Jay Nugent 1 on 20/11/2020 08:50:07

[Andy_GParticipant @andy_g]

I’d respectfully suggest using it as it is for a week or two to get the feel of it (making minor adjustments such as slideway gibs, etc.) before launching into a full strip-down.

Sometimes taking things to bits introduces new problems!

[SillyOldDufferModerator @sillyoldduffer]

Posted by Andy Gray 3 on 20/11/2020 09:01:03:

I’d respectfully suggest using it as it is for a week or two to get the feel of it (making minor adjustments such as slideway gibs, etc.) before launching into a full strip-down.

Sometimes taking things to bits introduces new problems!

+1 Or longer!

The urge to strip down new toys is almost irresistible, but don't do it as a first step! Although mini-lathes aren't delicate there are many opportunities for beginner blunders. One example, gibs go back in one way. Not unusual for enthusiastic innocents to put them in upside down, or the wrong way round, or fail to notice the adjusting screws are meant to engage with dimples (usually). And a certain amount of skill is needed to adjust correctly assembled gibs for best smooth running tightness, end to end.

When the new owner asks for help on the forum, it's hard for this end of the internet to tell the difference between worn-out, needs normal adjustment, and incorrectly assembled faults if someone has been 'at it'. Worst of all when several assembly mistakes are made.

Another booby trap, beginners often try and machine random scrap or DIY store metal, unaware that much of it is nasty stuff. All too easy to assume the machine is wrong and start fixing it, when the real problem is an inexperienced operator struggling with difficult material.

Take it step by step. Strip down after using the lathe reveals something needs attention. Cutting metal reveals faults better than any other approach. Reassembly is much safer when the machine and it's quirks are understood. It doesn't take long!

Dave

[Howard LewisParticipant @howardlewis46836]

On the subject of material, AVOID rebar. It is horrible material,. Don't know what is in it, but getting a reasonable, let alone a good one, is difficult.

Howard

[UncouthJParticipant @uncouthj]

A very true and sensible point, thanks Andy and Dave for the reality check.

Forgetting my fundamentals there.
Step 1: Put kettle on n have a hobnob…

I’ve been reading/watching up about levelling and test bars etc. So that’s probably a good first step to take, square everything up and remove as many environmentals from the equation as possible, and really see what’s what with the thing, prior to any thoughts of surgery.

Absolutely Howard. I’ve had some bad experiences with rebar myself. Pretty sure the only thing its good for is burying in concrete. I’ll grab some nice FM bar stock.

[Jon LawesParticipant @jonlawes51698]

I love seeing people start/restart/come back to this hobby. You have so much enjoyment ahead.

Enjoy your new machine

Jon

[UncouthJParticipant @uncouthj]

Thanks Jon, I very much intend to!

[BC ProfParticipant @bcprof]

Jay , I have sent you a PM Re "levelling "

Brian

[UncouthJParticipant @uncouthj]

Posted by BCPROF on 20/11/2020 16:03:44:

Jay , I have sent you a PM Re "levelling "

Brian

A good tip indeed! Thanks again

[Nicholas FarrParticipant @nicholasfarr14254]

Hi jay, just though I'd post a photo of my Chester mini lathe one, this has the seal intact.

Regards Nick.

[UncouthJParticipant @uncouthj]

Thanks for that Nick

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