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Harrison L5 - removing feedshaft, lead screw and associated paraphernalia!

Need advice on how to strip this part of the machine

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James Hughes 116/05/2020 22:55:45
7 forum posts

Hello all, new here, registered because trying to find some information that Google has failed to find.

I have a Harrison L5 11" lathe which I am current 'refurbishing'. Which basically means cleaning and painting, and ensuring it's all greased and oiled correctly., rather than a complete strip down and rebuild.

I wasn't planning on taking off the saddle/apron, leadscrews etc, but actually, now wondering whether it would be better to do so. I have no idea how to though and I am limited in space - for example I cannot draw out the screws as I only have 30cm of space on the right before I hit a wall.

So, can I remove the saddle/apron, then the screws? If so what is the correct procedure? ALl pointers welcome!

Rgds

James

Brian Wood17/05/2020 11:06:37
2186 forum posts
37 photos

Hello James,

Welcome aboard and enjoy the ride!

I imagine this model will be pretty similar to many others and perhaps the following generic description will help you.

First, disconnect the leadscrew and power shaft support from the tailstock end of the lathe bed.

Now disconnect the power shaft and leadscrew at the gearbox end of the lathe. Details will vary machine to machine but it is likely the power shaft will be coupled via a external sleeve with taper pin attachment at both ends of the sleeve. Release the one on the saddle side by tapping it out [do note which way the taper pin fits!!]

The leadscrew may enter the gearbox in a support bearing that is either bolted to or into a recess in the gearbox. Remove the bolts and set them aside. Engage the half nuts on the leadscrew and gently crank the saddle handwheel. With luck you may be able to draw both shafts free of the gearbox

Now you have the saddle, apron and both the shafts free as a combined unit. Look for the bolts holding the apron up onto the saddle. They will be cap head, often 4 but maybe 6 in total, Put a support below the apron to take the weight as you unbolt the two. Note if a short or extra long bolt is fitted in one position. Release the securing bolts and then carefully lower the apron, with it's two shafts still in place, down into the swarf tray.

The saddle should now be free to slide along the bed out of the way. Lift the apron clear of the swarf tray, it will be heavy so be prepared for that, and set aside for your attention.

A WORD OF WARNING Do not withdraw the power shaft without having taken the precaution to make a dummy in a piece of wood dowelling, complete with a keyway. If you look inside you will see one or maybe two worms that are driven by that shaft. They will be flanked by thrust bearings on both sides and it will save you a lot of grief later to use the dummy shaft to support all that by "chasing" the power shaft out as you withdraw it. For added security, fit a hose clip to each end of the dowelling to keep it in place as you work on the apron later.

The leadscrew should just withdraw but use your loaf and check there isn't some cunning interlock that drops out without the shaft being in position to keep it there.

Rebuild in a reverse of the procedure above.

The saddle will have underbed clamp strips both front and back. Removing these will allow you to lift the whole saddle off the bed. Look carefully at the orientation of these clamp strips, they may be thicker on one side. Note which that is and reinstate it the same way. The saddle will be lighter to lift if you unbolt the compound slide and lift that free

Kind regards Brian

Edited By Brian Wood on 17/05/2020 11:07:15

Edited By Brian Wood on 17/05/2020 11:15:24

James Hughes 117/05/2020 13:06:07
7 forum posts

Wow, some fantastic detail there! Thank you! My main concern was how to withdraw the screws from the gearbox, but will check to see what sort of pinning arrangement there is. There is a slightly duff brass screw in the leadscrew that is of some concern.

On the whole though it does sound feasible for me to do!

Thanks again. If anyone has any specific information on how the shafts attach at the gearbox end that would be splendid. I'll try and grab some photos showing what it looks like.

Brian Wood17/05/2020 13:54:18
2186 forum posts
37 photos

Hello James,

"Slightly duff brass screw in the leadscrew"--what's that all about I wonder?

Anyway, glad to be of help. Use the procedure as a road map and adjust according to local conditions, I don't think you will go far wrong

Machine specific information would though be useful for you, there must be many on the Forum with one of these lathes who can give you that detail

Kind regards Brian

Alexander Smith 117/05/2020 14:31:12
29 forum posts
20 photos

Hi James,

I have a Harrison 140 which is essentially the metric version of the L5(not exactly, I know, but close enough) and have the manual. If you don't have a copy already, I could let you have the relevant diagrams.

sandy

James Hughes 117/05/2020 14:34:33
7 forum posts
Posted by Brian Wood on 17/05/2020 13:54:18:

"Slightly duff brass screw in the leadscrew"--what's that all about I wonder?

There is a flat blade screw in to what looks like a bit of keyway, but the head is damaged, so might need to be drilled out. I'll take a photo.

James Hughes 117/05/2020 14:35:26
7 forum posts
Posted by Alexander Smith 1 on 17/05/2020 14:31:12:

Hi James,

I have a Harrison 140 which is essentially the metric version of the L5(not exactly, I know, but close enough) and have the manual. If you don't have a copy already, I could let you have the relevant diagrams.

sandy

That would be splendid! I have no diagrams/cutaways for the lathe at all, hence my questions - worried about taking something off and not being able to get it back again!

James Hughes 117/05/2020 18:06:56
7 forum posts

Here's a video of the couplings at gearbox end if it helps anyones to suggest anything.

https://photos.app.goo.gl/mQR3qaK6V7hqa9Ra7

Andy Stopford17/05/2020 20:19:36
24 forum posts
1 photos

It's 20 years since I last took my L5 apart so I can't give you exact details, but it's mostly straightforward - I don't recall any need to use a dummy feedshaft.

One gotcha though is that the support at the right hand end of the bed is located by dowels pointing forwards, and the apron is located by dowels pointing upwards, therefore trying to remove one conflicts with the other (You're intended to remove the end nuts and slide the leadscrew and feed shaft out to the right, but you haven't the space to do this).

However (as I remember) if you support the apron and remove the screws securing the end bracket, apron and screw-cutting gearbox, it's possible to wiggle everything free from its dowels - take care, you are depending on springing the leadscrew and feedshaft slightly, but if you're just using finger pressure you're not going to put a permanent bend in them, use no crowbars! It might be a good idea to have assistance to avoid the weight of the apron hanging on the shafts.

The leadscrew isn't fixed to the gearbox, its end just locates in a bronze bush. The feedshaft, I can't remember, I think that might just pull out as well.

I'm (sadly) selling my L5 after we return (more or less) to normality, and to extract it from the friend's workshop where it currently resides will require it to be totally stripped down. Oh joy...

edit: forgot to say, mine (which is the 9" model) doesn't have the 'duff brass screw' but I presume it's something to do with securing the dog clutch to the feedscrew, and if so it shouldn't need to be disturbed.

Edited By Andy Stopford on 17/05/2020 20:26:13

James Hughes 118/05/2020 09:23:13
7 forum posts

Thanks to all who have commented - all great information!

(Just wait till I start on the Adcock/Shipley ES1 mill - I know NOTHING about that, and it needs quite some TLC)

Brian Wood18/05/2020 11:13:09
2186 forum posts
37 photos

Hello James,

Neither do I so you will need input from an owner, most assuredly!

Glad to have been of help with the lathe

Regards Brian

Alexander Smith 119/05/2020 12:20:12
29 forum posts
20 photos

Hi James,

turned the office upside trying to find my copy of the manual to no avail but I found that you can download a full copy of the manual free from www.vintagemachinery.org. Look in the publications section. Great site with hundreds of manuals form old machines. All the info and exploded diagrams you need are on there. Sandy

James Hughes 119/05/2020 15:12:29
7 forum posts
Posted by Alexander Smith 1 on 19/05/2020 12:20:12:

Hi James,

turned the office upside trying to find my copy of the manual to no avail but I found that you can download a full copy of the manual free from www.vintagemachinery.org. Look in the publications section. Great site with hundreds of manuals form old machines. All the info and exploded diagrams you need are on there. Sandy

Thanks for trying to find them!. Have found some L5 docs on the site you linked to. Some good cutaways, need to read more detail on servicing process!

James

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