Author Topic: Harrison 140 lathe question  (Read 1430 times)

Offline Ian.C

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Harrison 140 lathe question
« on: February 08, 2017, 02:03:27 PM »
Hi everyone, I wonder if anyone can tell me what thread the adjusting/leveling screws are as I need to tap out the rather crusty threads on my new toy, the lathe didn't come with the screws! I have measured the diameter of the bolts and found 21.9mm and 3mm pitch-ish but I would have thought they would been imperial. It is a metric lathe though?









Online awemawson

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Re: Harrison 140 lathe question
« Reply #1 on: February 08, 2017, 03:41:25 PM »
Hi Ian welcome !

Can I suggest that if you are going to be using your new lathe much it's worth while investing is a screw pitch gauge. They are cheap as chips and will serve you well for years to come identifying threads - you'll need a caliper gauge as well to measure the diameter accurately.
« Last Edit: February 08, 2017, 04:32:09 PM by awemawson »
Andrew Mawson
East Sussex

Offline philf

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Re: Harrison 140 lathe question
« Reply #2 on: February 08, 2017, 04:05:15 PM »
Ian,

It's possibly 7/8" BSW which is 9 TPI (2.822mm Pitch) You did say 3mm-ish.

Phil.
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Offline Ian.C

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Re: Harrison 140 lathe question
« Reply #3 on: February 09, 2017, 06:19:31 AM »
Hi Phil,

Thanks a lot for that, I didn't think the thread would be metric - I have ordered a set of imperial pitch gauges, I only had a metric set. I will report back.

Offline micktoon

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Re: Harrison 140 lathe question
« Reply #4 on: February 09, 2017, 12:43:18 PM »
Hi Ian, yes I can confirm 7/8 Whitworth threads on the levelling bolts.
  Cheers Mick  :thumbup:

Offline Ian.C

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Re: Harrison 140 lathe question
« Reply #5 on: February 09, 2017, 02:38:04 PM »
Thanks Mick, I have just ordered a new tap. She is getting a bit of a paint job this weekend not ideal weather conditions but I cant wait to start making some swarf. Ian

Offline Ian.C

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Re: Harrison 140 lathe question
« Reply #6 on: February 17, 2017, 05:25:19 PM »
Thanks to Mick and every one else the threads have now been chased out. I borrowed an engineers level and have the lathe as level as its ever going to be in my possesion, the level is accurate to 0.3mm and I focused my patience towards the front to back rather than along the length - I wish i knew the correct terminology! I was more concerned about twisting the bed. I will be making chips and swarf tomorrow. Ian

Offline micktoon

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Re: Harrison 140 lathe question
« Reply #7 on: February 17, 2017, 06:00:42 PM »
Hi Ian , glad you managed to get it sorted out in the end   :thumbup:
  Cheers Mick

Online awemawson

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Re: Harrison 140 lathe question
« Reply #8 on: February 18, 2017, 03:03:22 AM »
Thanks to Mick and every one else the threads have now been chased out. I borrowed an engineers level and have the lathe as level as its ever going to be in my possesion, the level is accurate to 0.3mm and I focused my patience towards the front to back rather than along the length - I wish i knew the correct terminology! I was more concerned about twisting the bed. I will be making chips and swarf tomorrow. Ian

Along the bed is the Z axis, and across the bed is the X axis
Andrew Mawson
East Sussex

Offline mattinker

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Re: Harrison 140 lathe question
« Reply #9 on: February 18, 2017, 05:54:23 AM »
The Z axis is the driven axis.

All the best, Matthew

Offline Ian.C

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Re: Harrison 140 lathe question
« Reply #10 on: February 19, 2017, 11:02:43 AM »
Thanks again chaps. I've had it running but found an oil leak coming from the gear box top lid so i will have to have a look at that.

Offline Biggles

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Re: Harrison 140 lathe question
« Reply #11 on: February 19, 2017, 03:34:03 PM »
I think John (doubleboost) had the same problem. He solved it by using some gasket sealer.  :coffee:

Offline Ian.C

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Re: Harrison 140 lathe question
« Reply #12 on: February 20, 2017, 03:35:29 PM »
Thanks just watched the video.

Offline Biggles

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Re: Harrison 140 lathe question
« Reply #13 on: February 21, 2017, 08:16:01 AM »
your Welcome.  :thumbup:

Offline trevoratxtal

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Re: Harrison 140 lathe question
« Reply #14 on: February 26, 2017, 01:45:36 PM »
Worth noting the 140 was designed to go on the back of a Army or Air Force 10 ton Truck or in the engineering shop of a ship, frigate or battle ship. So leveling is not essential but preferred.
That is why it is Near fatal to ever part the lathe from the special frame it is bolted to.
For that reason it is the only lathe I know that can be put on wheels and still stay accurate.
Mine is on wheels ! I posted a pics long ago
Trev

 :)

Offline Ian.C

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Re: Harrison 140 lathe question
« Reply #15 on: March 04, 2017, 02:48:15 AM »
Hi Trevor, Thanks for the information. I ended up leveling it really well. I am still trying to get my head around all the levers and their functions! I still cant figure out what the lever to the right of the half nut lever is for - I am new to the machining world. Ian

Online awemawson

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Re: Harrison 140 lathe question
« Reply #16 on: March 06, 2017, 08:42:31 AM »
You'd expect to find three levers on a lathe carriage:

Threading Half Nut Engage

Feed Engage

and

Select Long Feed (Z) or Cross Feed (X)

In addition some lathes with the ability to knock their feed off when hitting a stop will also have a knob to adjust the force needed to 'knock off'
Andrew Mawson
East Sussex

Offline AdeV

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Re: Harrison 140 lathe question
« Reply #17 on: March 06, 2017, 04:14:54 PM »
This drawing might help... it's of the Harrison L11, but according to the source site (www.lathes.co.uk - well worth finding your lathe on there & reading about it), the internals of the 140 are basically the same. So all the levers and wheels should be the same... (famous last words):



Here's a link to the 140: http://www.lathes.co.uk/harrison/page13.html
Cheers!
Ade.
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Or: Zhengzhou, China. An even longer way from anywhere...
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Offline Ian.C

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Re: Harrison 140 lathe question
« Reply #18 on: March 08, 2017, 08:57:48 AM »
Thanks again everyone. It was the leadscrew engaging lever I was referring to according to the above image, I have been using the feedshaft engaging lever to traverse the "X" axis when machining along the length, which of these two levers operate the half nuts. I am assuming that the lead screw is for creating threads and the feedshaft is for the cross slide operation?? :Doh:

Online awemawson

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Re: Harrison 140 lathe question
« Reply #19 on: March 08, 2017, 09:00:12 AM »
Correct  :thumbup:

Keep the screw feed for threading to preserve the accuracy of the screw shaft.
Andrew Mawson
East Sussex

Offline Ian.C

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Re: Harrison 140 lathe question
« Reply #20 on: March 08, 2017, 03:53:36 PM »
Thanks for that - I'm getting there slowly.

Offline Biggles

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Re: Harrison 140 lathe question
« Reply #21 on: March 10, 2017, 12:27:44 PM »
Just a thought; you probably know this already. dont engage both the feed and the half nuts leavers at the same time. its one or the other.
 :doh:

Offline seadog

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Re: Harrison 140 lathe question
« Reply #22 on: March 10, 2017, 01:48:22 PM »
Is that possible? Surely there is a mechanical interlock that would preclude this happening?

Offline shipto

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Re: Harrison 140 lathe question
« Reply #23 on: March 10, 2017, 04:15:57 PM »
Is that possible? Surely there is a mechanical interlock that would preclude this happening?
I think this very thing has happened on mine, I had to replace the feed cog on mine as it had been pretty much stripped clean and someone at some time or other has put a bolt into the leadscrew engage lever to stop it dropping and engaging by accident.
not a very good pic but you can just about see it.
edit: should have said mine is a 14" not a 140
« Last Edit: March 10, 2017, 05:47:29 PM by shipto »
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Offline doubleboost

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Re: Harrison 140 lathe question
« Reply #24 on: March 10, 2017, 05:29:03 PM »
 My 140 has a interlock to prevent this from happening
The leadscrew also has a "dog" clutch to stop the lead screw needsley turning
John