Harrison lathe clutch

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Harrison lathe clutch

This topic has 19 replies, 7 voices, and was last updated 2 January 2020 at 18:15 by Matthew White 3.

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31 January 2018 at 10:47 #339173
dw dw 1
Participant
@dwdw1
Hello all, hope someone can help. I have just taken apart the clutch mech' on my Harrison L5 lathe (see pic). Between the halo disc (28) & the R.H. clutch plate (27) the previous owner has put a piece of thick wire bent into a circle (see pic) as some kind of washer/spacer. I have the washers that adjust the clutch slip (36) but (37) washer for L5A is not there, I am wondering if the wire spacer has been put in as replacement in error for washer (37) which is present on L5A clutch?Has anyone got any info on this wire spacer or a photo of their clutch mech' or a link to a different parts drawing.All the best DW.
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31 January 2018 at 10:47 #13127
dw dw 1
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@dwdw1
31 January 2018 at 11:11 #339175
dw dw 1
Participant
@dwdw1
31 January 2018 at 11:11 #339176
dw dw 1
Participant
@dwdw1
31 January 2018 at 11:14 #339177
dw dw 1
Participant
@dwdw1
31 January 2018 at 11:17 #339178
dw dw 1
Participant
@dwdw1
31 January 2018 at 19:10 #339218
Howard Lewis
Participant
@howardlewis46836
One possible solution would be if some kind soul happens to have the Washer that you need, surplus to requirements, and is prepared to part with it.

Failing that, maybe they could give you the dimensions, and possibly an idea of the material spec?

That would then leave you with Catch 22, of needing a lathe to make one!

If that is the case, no doubt, someone on here will be near enough to you to be able to make it for you.

Just suggestions.

Howard
1 February 2018 at 10:11 #339291
norm norton
Participant
@normnorton75434
I would just try a washer that approximates in thickness to the piece of wire. The previous user might have put it in to compensate for wear and to get back some adjustment.

You need to go to the Harrison Yahoo site with this question where there are people with specific Harrison knowledge, and there is even a current thread on the L5 clutch! **LINK**

Norm
1 February 2018 at 11:21 #339297
Brian Wood
Participant
@brianwood45127
I think I can understand why the piece of wire was put in—some crisis arose in the middle of an urgent job and this made a working fix to get the job running again without having to tear down the spindle to fit it.

A 'bodge' that kept the machine running and the sort of solution a busy machine shop would come up with.

If that is correct then a washer of the same thickness as the wire will be a suitable replacement, the remaining unknown would be it's stage of hardness

Brian
1 February 2018 at 14:12 #339313
dw dw 1
Participant
@dwdw1
Posted by norm norton on 01/02/2018 10:11:51:

I would just try a washer that approximates in thickness to the piece of wire. The previous user might have put it in to compensate for wear and to get back some adjustment.

You need to go to the Harrison Yahoo site with this question where there are people with specific Harrison knowledge, and there is even a current thread on the L5 clutch! **LINK**

Norm

Thanks Norm, just joined. All the best DW.
1 February 2018 at 14:19 #339315
dw dw 1
Participant
@dwdw1
Posted by Brian Wood on 01/02/2018 11:21:18:

I think I can understand why the piece of wire was put in—some crisis arose in the middle of an urgent job and this made a working fix to get the job running again without having to tear down the spindle to fit it.

A 'bodge' that kept the machine running and the sort of solution a busy machine shop would come up with.

If that is correct then a washer of the same thickness as the wire will be a suitable replacement, the remaining unknown would be it's stage of hardness

Brian

Thanks Brian. I made a washer same thickness. Then I looked again at the parts drawing the washer (36) is between bearing (30) & cluch plate (28) so the wire is actually the wrong side of the pulley. The bearing cage is broken in one place (ordered replacement) so am now ondering if the wire was put there to stop bearing falling out??
1 February 2018 at 17:55 #339345
Brian Wood
Participant
@brianwood45127
Hello DW,

I'm not familiar with Harrison lathes, so I can't help you decide what went wrong but I am still willing to bet this was a 'get the job done for f**k's sake and worry about the lathe later'

The thing is it never got done and I also think the washer was hardened originally and fractured in some kind of accident. It takes some determination to break a bearing cage and a pound to a pinch of muck says the bits of washer jiggered it up.

Are there any other forensic clues you can see?

Regards Brian
2 February 2018 at 08:58 #339428
dw dw
Participant
@dwdw40549
The bearing & its cage was v.loose when I took it all apart, it came out easily leaving behind the bearing cup.
2 February 2018 at 09:03 #339429
dw dw
Participant
@dwdw40549
Subsidery question, I need to find replacement nut that holds changewheels in place on parts dia' nuts are listed as 7/8 F.B. What does the F.B. stand for? I measured the thread & its whitworth 55 degree, 12G. I assume the 12 means 12 threads per inch, what does the G stand for?
2 February 2018 at 09:22 #339431
Brian Wood
Participant
@brianwood45127
Hello DW,

Sorry, you've got me there, it is not an abbreviation I have come across. Someone else will know

Regards Brian
2 February 2018 at 09:39 #339435
Michael Gilligan
Participant
@michaelgilligan61133
Posted by dw dw on 02/02/2018 09:03:20:

… what does the G stand for?

.

See my post 13/06/2015 here: **LINK**

http://www.model-engineer.co.uk/forums/postings.asp?th=107919

MichaelG.
2 February 2018 at 10:23 #339442
dw dw
Participant
@dwdw40549
So we learn something new every day, cheers….DW.
2 February 2018 at 18:17 #339497
Howard Lewis
Participant
@howardlewis46836
According to my ZEUS charts,

NO BSP (aka Gas) thread is 12 tpi.

7/8 BSW is 9 tpi

7/8 BSF is 11 tpi.

The Whitworth form threads with 12 tpi are; 3/4 BSF , 1/2" and 9/16" BSW.

Just to add confusion:

In the unlikely event that the thread was 60 degrees, it could be 9/16 UNC, 1" UNF or if Metric, M22 with a pitch of 2.5mm (0.098" ) an unusual pitch of 2.11mm would equate to 0.083" or 12 tpi . 2 mm pitch would equate to 0.0787" almost 13 tpi, (0.0769" pitch).

The important information that you need is:

Diameter, and Pitch or tpi of the male thread to which you want fit the new nut?

You might even find that it is a special for this shaft! If so, unless you can find one as a spare, you will definitely have to make one.

Don't think that "FB" would be an abbreviation for "Funny B*****" rather than "Fine Bored"?

Howard

Edited By Howard Lewis on 02/02/2018 18:18:16

Edited By Howard Lewis on 02/02/2018 18:18:35
4 February 2018 at 12:20 #339738
dw dw 1
Participant
@dwdw1
looks like the 55 deg whit 12G was a one off used on this lathe. Have now found some on ebay. Cheers all.

DW.
2 January 2020 at 18:15 #444355
Matthew White 3
Participant
@matthewwhite3
Hi I'm new to the site and i apologize for not introducing myself on the other forum but need some help on this topic. I have acquired a Harrison L6 12" x 24" MK2 lathe over the Christmas period and the clutch lever didn't work there was permanent drive through the gear box. I have found the issue in that even with the clutch removed the clutch pulley is really stiff and still turns the gearbox input shaft when it should be freely rotating/disconnected from the shaft.

I have tried as far as i dare to remove the clutch pulley to inspect/clean it but i cannot free it from the input shaft. Are there any hidden circlips or pins that stop this pulley being pulled off. the whole unit will rock and pull push a couple of mm but that is it.

I haven't been able to source a manual for mine or any videos etc to show how this pulley is removed

any help will be appreciated.
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