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Gallery, Projects and General => Project Logs => Topic started by: Ian.C on February 08, 2017, 02:03:27 PM

Title: Harrison 140 lathe question
Post by: Ian.C 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?



(http://i291.photobucket.com/albums/ll287/solidlifter/Harrison_zpsxydrigx6.jpg) (http://s291.photobucket.com/user/solidlifter/media/Harrison_zpsxydrigx6.jpg.html)




Title: Re: Harrison 140 lathe question
Post by: awemawson 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.
Title: Re: Harrison 140 lathe question
Post by: philf 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.
Title: Re: Harrison 140 lathe question
Post by: Ian.C 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.
Title: Re: Harrison 140 lathe question
Post by: micktoon 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:
Title: Re: Harrison 140 lathe question
Post by: Ian.C 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
Title: Re: Harrison 140 lathe question
Post by: Ian.C 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
Title: Re: Harrison 140 lathe question
Post by: micktoon on February 17, 2017, 06:00:42 PM
Hi Ian , glad you managed to get it sorted out in the end   :thumbup:
  Cheers Mick
Title: Re: Harrison 140 lathe question
Post by: awemawson 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
Title: Re: Harrison 140 lathe question
Post by: mattinker on February 18, 2017, 05:54:23 AM
The Z axis is the driven axis.

All the best, Matthew
Title: Re: Harrison 140 lathe question
Post by: Ian.C 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.
Title: Re: Harrison 140 lathe question
Post by: Biggles 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:
Title: Re: Harrison 140 lathe question
Post by: Ian.C on February 20, 2017, 03:35:29 PM
Thanks just watched the video.
Title: Re: Harrison 140 lathe question
Post by: Biggles on February 21, 2017, 08:16:01 AM
your Welcome.  :thumbup:
Title: Re: Harrison 140 lathe question
Post by: trevoratxtal 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

 :)
Title: Re: Harrison 140 lathe question
Post by: Ian.C 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
Title: Re: Harrison 140 lathe question
Post by: awemawson 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'
Title: Re: Harrison 140 lathe question
Post by: AdeV 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):

(http://www.lathes.co.uk/harrison/img15.gif)

Here's a link to the 140: http://www.lathes.co.uk/harrison/page13.html (http://www.lathes.co.uk/harrison/page13.html)
Title: Re: Harrison 140 lathe question
Post by: Ian.C 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:
Title: Re: Harrison 140 lathe question
Post by: awemawson on March 08, 2017, 09:00:12 AM
Correct  :thumbup:

Keep the screw feed for threading to preserve the accuracy of the screw shaft.
Title: Re: Harrison 140 lathe question
Post by: Ian.C on March 08, 2017, 03:53:36 PM
Thanks for that - I'm getting there slowly.
Title: Re: Harrison 140 lathe question
Post by: Biggles 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:
Title: Re: Harrison 140 lathe question
Post by: seadog on March 10, 2017, 01:48:22 PM
Is that possible? Surely there is a mechanical interlock that would preclude this happening?
Title: Re: Harrison 140 lathe question
Post by: shipto 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
Title: Re: Harrison 140 lathe question
Post by: doubleboost 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
Title: Re: Harrison 140 lathe question
Post by: hanermo on March 11, 2017, 11:13:08 AM
This may be so, but I think, honestly, not..
All sorts of lathes by thousands have been used on ships and boats of all types for decades and worked fine.

As you said, if it has an accurate-to-lathe-body (spindle) subframe, this will be a great help, and You can just move it / chuck the subframe into any place and it will be fine.
No personal experience on that lathe.

But boats/yachts/ships twist, quite a lot, in machinist terms.
This does not hurt any lathe, but for top-accuracy the lathes should theoretically be soft-mounted on relatively rigid subframes.
Afaik, this is not routinely done.

A huge nr of manual lathes are on soft mounts and do excellent work.
The common wisdom and factory recommendation on manual lathes is soft mounts.

I am not advocating/insisting on soft mounts ...
just pointing out they are the common-average factory recommendation, and work well.
A hard mount is modern practice with big cnc turning centers (+vmcs), that are all soft and floppy, volumetrically.


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

 :)
Title: Re: Harrison 140 lathe question
Post by: Biggles on March 11, 2017, 03:08:59 PM
Not too sure of all models John. My old L5a you can engage both if you so wish. Having said that, there are security shear pins, one is the connection between the cross slide screw and gearwheel and the other is in gear box. (Haven’t seen this one though). There could also be another in the saddle. (For those not in the know these taper pins are made of mild steel and designed to sheer when excess force is applied to the machine mechanisms) (Obviously don’t mean you John  :bow:).
Title: Re: Harrison 140 lathe question
Post by: Ian.C on March 14, 2017, 02:38:21 AM
Thanks again chaps. I'm attempting to make a 3C collet block!
Title: Re: Harrison 140 lathe question
Post by: Biggles on March 15, 2017, 01:35:12 PM
Good on you Ian, lots of pictures please.  :thumbup: