MadModder

The Shop => Our Shop => Topic started by: doubleboost on February 22, 2015, 12:25:32 PM

Title: New Lathe
Post by: doubleboost on February 22, 2015, 12:25:32 PM
Hi
Lads
Bought a new toy today
140 Harrison
It was great to open the sized door & find it full of mint chucks & steadies
Brought some bits home lathe coming next Saturday
(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340012_zpsmiugpz9k.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340012_zpsmiugpz9k.jpg.html)

(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340006_zpsvolmxqpx.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340006_zpsvolmxqpx.jpg.html)

(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340007_zps2lcpjzii.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340007_zps2lcpjzii.jpg.html)

(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340005_zpsvnpnfxco.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340005_zpsvnpnfxco.jpg.html)
(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340003_zpskkp1ok3s.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340003_zpskkp1ok3s.jpg.html)
(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340009_zpspijerfhz.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340009_zpspijerfhz.jpg.html)
(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340008_zpslzkjhd2n.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340008_zpslzkjhd2n.jpg.html)

John


Title: Re: New Lathe
Post by: Bigbadbugga on February 22, 2015, 12:38:17 PM
Nice  :beer:

I know you said you were looking for a bigger lathe, how much bigger than the boxford is this in real terms?

You gonna do some videos of its installation John?

Would make some interesting viewing in my opinion.
Title: Re: New Lathe
Post by: awemawson on February 22, 2015, 12:38:56 PM
Nice one John - a good make and model I think  :thumbup:

What do you know of it's background - education or industry ?

(Education = little wear but possibly carriage /chuck crashes, industry = potentially much wear but probably less abuse)
Title: Re: New Lathe
Post by: lordedmond on February 22, 2015, 12:40:07 PM
Nice pressy you have there john

All you have to do is make room for it , is the sparky bits compatible or are you going the VFD route

Have fun but do look after Debs just keep ticking off the chemo sessions soon it will be half way then the numbers look a lot better that's the way we did it

Stuart
Title: Re: New Lathe
Post by: doubleboost on February 22, 2015, 12:44:34 PM
Nice one John - a good make and model I think  :thumbup:

What do you know of it's background - education or industry ?

(Education = little wear but possibly carriage /chuck crashes, industry = potentially much wear but probably less abuse)

I would say basically unused no crash damage & no wear
Very light surface rust & grease
John
Title: Re: New Lathe
Post by: doubleboost on February 22, 2015, 12:46:40 PM
Nice pressy you have there john

All you have to do is make room for it , is the sparky bits compatible or are you going the VFD route

Have fun but do look after Debs just keep ticking off the chemo sessions soon it will be half way then the numbers look a lot better that's the way we did it

Stuart

Be halfway this Friday
It was running of the phase converter
John
Title: Re: New Lathe
Post by: doubleboost on February 22, 2015, 12:49:41 PM
Nice  :beer:

I know you said you were looking for a bigger lathe, how much bigger than the boxford is this in real terms?

You gonna do some videos of its installation John?

Would make some interesting viewing in my opinion.

It has a fair bit more capacity than the Boxford (diameter wise) about the same distance between centres
No drive belt to slip
Be plenty of vids to come
Be a short clip in this evenings night cap
John
Title: Re: New Lathe
Post by: NormanV on February 22, 2015, 01:13:54 PM
If you find that it is too big for your space I am sure that I could fit it in here.
Title: Re: New Lathe
Post by: mfletch on February 22, 2015, 01:19:53 PM
Nice one John I bet its a 3HP motor I've got my L6 running through a phase inverter it make it easier to use

4 Jaw Pratt chuck nice
Title: Re: New Lathe
Post by: Manxmodder on February 22, 2015, 02:40:35 PM
Nice one John, you'll not regret buying that. My L6 came out of a training college similarly well equipped with faceplates, Pratt 3 and 4 jaw chucks,multisize collets etc.

I might one day consider adding a longer bed lathe to my collection,like a DS&G, but I wouldn't part with the Harrison....OZ.

 
Title: Re: New Lathe
Post by: Manxmodder on February 22, 2015, 02:50:09 PM
Nice one John I bet its a 3HP motor I've got my L6 running through a phase inverter it make it easier to use

4 Jaw Pratt chuck nice

Fletch,I forgot that you also have an L6.
 Which phase converter package do you use to run the original 3 hp motor?
 I've still got the original 3 phase motor for mine in storage,but currently have a 2 horse single phase fitted.....OZ.
Title: Re: New Lathe
Post by: vtsteam on February 22, 2015, 03:15:42 PM
Congrats!  :thumbup: :thumbup: :clap:
Title: Re: New Lathe
Post by: Stilldrillin on February 22, 2015, 03:49:01 PM
That's a nice package, John!   :bugeye:

Enjoy!  :thumbup:

David D
Title: Re: New Lathe
Post by: micktoon on February 22, 2015, 04:31:19 PM
Hi John, Good news on the lathe and goodies with it.
The only thing in history that even comes close to when the cabinet door became unseized and swang open to reveal a full set of tooling , was Howard Carter opening Tutankharmun's tomb  :drool: :drool: but far as I know he did not find a Pratt 4 jaw so you still edge it by a mile  :thumbup:

  Welcolme to the Worshipful Guild of Harrison lathe owners  :clap:

  Cheers Mick
Title: Re: New Lathe
Post by: Ginger Nut on February 22, 2015, 04:39:38 PM
Hi John, Good news on the lathe and goodies with it.
The only thing is history that even comes close to when the cabinet door became unseized and swang open to reveal a full set of tooling , was Howard Carter opening Tutankharmun's tomb  :drool: :drool: but far as I know he did not find a Pratt 4 jaw so you still edge it by a mile  :thumbup:

  Welcolme to the Worship Guild of Harrison lathe owners  :clap:

  Cheers Mick

Mick he'll need it fully stripped down and repainted a nice Pink or Purple just so it doesn't clash with yours  :beer:

Title: Re: New Lathe
Post by: Manxmodder on February 22, 2015, 04:43:01 PM
Hi John, Good news on the lathe and goodies with it.
The only thing is history that even comes close to when the cabinet door became unseized and swang open to reveal a full set of tooling , was Howard Carter opening Tutankharmun's tomb  :drool: :drool: but far as I know he did not find a Pratt 4 jaw so you still edge it by a mile  :thumbup:

  Welcolme to the Worship Guild of Harrison lathe owners  :clap:

  Cheers Mick

Mick he'll need it fully stripped down and repainted a nice Pink or Purple just so it doesn't clash with yours  :beer:

It will have to be green,John loves green on machines,it's his favourite colour :lol: :lol:
Title: Re: New Lathe
Post by: Bigbadbugga on February 22, 2015, 05:29:56 PM

Just watched the nightcap, much better format with it being one part.

Looks like a nice upgrade from the boxford.
Title: Re: New Lathe
Post by: sbwhart on February 23, 2015, 01:34:04 AM
Nice score John

I can see some nice working coming from it.

Stew
Title: Re: New Lathe
Post by: Will_D on February 23, 2015, 08:00:07 AM
Hi John,
Hope all is going well for Debs and yourself.

Surprised no-one has aked "What are you doing withe the Boxford"?

I know you are super productive what with work/the workshop/the video productions but even you couldn't run two lathers at once!!

Plus it would take up all the walking space in the shop!
Title: Re: New Lathe
Post by: mfletch on February 23, 2015, 08:40:10 AM
Nice one John I bet its a 3HP motor I've got my L6 running through a phase inverter it make it easier to use

4 Jaw Pratt chuck nice

Fletch,I forgot that you also have an L6.
 Which phase converter package do you use to run the original 3 hp motor?
 I've still got the original 3 phase motor for mine in storage,but currently have a 2 horse single phase fitted.....OZ.

I use one of these but keep looking on ebay as you will find one cheaper I paid 160 off ebay new I will post some pictures when on a proper computer http://www.ebay.co.uk/itm/3hp-2200W-IMO-Jaguar-CUB-Inverter-Single-to-Three-Phase-Digital-Converter-VSD-/161588374389?pt=LH_DefaultDomain_3&hash=item259f6aeb75
Title: Re: New Lathe
Post by: Manxmodder on February 23, 2015, 10:47:55 AM
Cheers for the info mfletch,very much appreciated. That seems a really good quality unit and the manufacturers  5 year warranty is very reassuring as well.

I've been considering reinstalling the original 3 phase motor and a speed controlled inverter for a while now.
I look forward to seeing what setup John chooses to install on his new140....OZ.

Title: Re: New Lathe
Post by: John Rudd on February 23, 2015, 11:24:14 AM
Oz, the vsd that Fletch linked is for a 240v 3phase motor.....Your orig motor may not be suitable if it's the original .....check the name plate to see if its dual voltage.....star 415v or delta 240v.....
Title: Re: New Lathe
Post by: mfletch on February 23, 2015, 11:32:51 AM
Yes the motor on my L6 is a dual voltage so it can be changed between star and delta 240v or 415v
Title: Re: New Lathe
Post by: Manxmodder on February 23, 2015, 01:34:26 PM
Oz, the vsd that Fletch linked is for a 240v 3phase motor.....Your orig motor may not be suitable if it's the original .....check the name plate to see if its dual voltage.....star 415v or delta 240v.....

John,cheers for the reminder about star and delta,I was planning on having a look at the motor before making any purchase of a VSD.

Looking at the motor options for the L6 in the owners handbook there are various specs of motors depending on the spindle speed ranges,which differed on certain models.

The optional motor specs given for 3 phase 50 hz  are:
(single speed 1500rpm motors)
1.5 hp 34-750 rpm spindle speed
2 hp 45-1000 rpm     "           "

(Dual speed 1500/3000 rpm motor)
3.5 hp 34-1500 rpm spindle speed
3.5 hp 45-200   rpm     "         "

The spindle speeds chart on my lathe shows 45-1000rpm so it follows that the original motor is 2 hp.

mfletch just for interest,what spindle speed ranges does your L6 have,and is it a MK 1 version?......OZ.
Title: Re: New Lathe
Post by: mfletch on February 23, 2015, 01:47:47 PM
Mine is a Mk1 its had a replacement motor {not by me} 1500rpm 3HP; speed range 45-1000rpm

sorry John for the hijack

Title: Re: New Lathe
Post by: micktoon on February 23, 2015, 04:15:29 PM
Hi Oz , from what I have seen of Harrisons don't take anything for granted without seeing it with your own eyes, like your motor, what the manual says it will be and what it ended up having can be two different things with Harrison lol.
  I think John is going to run his off the rotary phase converter, I am not sure about this but I have heard somewhere that you need a special inverter to run a twin speed motor like John's 140 has fitted.
   Each speed on the gearbox has the normal speed as marked in the low range when the motor is running in low ( electrical ) speed 1500rpm range , then if you switch the motor to high speed range 3000rpm each gear selection would have the relevant double speed of the low motor range. So in effect twice as many gears.
  Not sure if it needing to be special inverter is correct or not ...........anyone else know ??

  Cheers Mick
Title: Re: New Lathe
Post by: Manxmodder on February 23, 2015, 05:24:57 PM
Hi Mick, you don't need to convince me that Harrisons made in that era were devoid of any predictable logic and completely random in deciding specs of their machines.

 They're often a bloody nightmare to source the right parts for because of these assembly inconsistencies.

I did wonder whether a normal inverter would cater for the 2 speed motor or a special unit was required.

On the subject of John's 140,what I did notice was the backlates etc in photos seem to be the L00 taper fitting which is a huge improvement over the threaded spindle like mine and micktoon's.

And John, you look ever so youthful and very fetching with the blonde wig on. :lol: :lol:.....OZ.
Title: Re: New Lathe
Post by: Ginger Nut on February 23, 2015, 05:39:56 PM
 :poke: Oh Oh whats to become of John & Mick will it be a case of  :hammer: fighting for bargains when out at Car boot sales for the Harrisons parts or will they  :med: over a  :beer: a share the spoils.

With spring coming on over there and the car boot sales starting soon John will have a wish list as long as his arms
Title: Re: New Lathe
Post by: micktoon on February 23, 2015, 06:12:23 PM
Hi Oz , I thought you would know about the curse of working out what is what with harrisons. Well spotted John's lathe is L00 taper nose , it is better but you can not really make backplates etc , well not as easy anyway  :bugeye:, lucky for John he has everything except I think there should be a 16 inch faceplate too.
  Hi Ginger nut, Yes we are looking forward to the car boot season starting again, we normally share the spoils anyway and we both have most lathe related stuff anyway now, we both think 2015 is the year we will come across 'The Mutha Load' ............... You know the one where the old guy is packing in and has his whole collection of engineering tooling for sale  :drool: :drool: :drool: .............................   Dream on eh  :lol: Who knows what goodies we will uncover  :thumbup:

  Cheers Mick.
Title: Re: New Lathe
Post by: doubleboost on February 23, 2015, 06:28:05 PM
Made a start cleaning some bits up

(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/Grabbed%20Frame%20164_zpslbumtt0k.png) (http://s261.photobucket.com/user/john970s0/media/HARRISON/Grabbed%20Frame%20164_zpslbumtt0k.png.html)

(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/Grabbed%20Frame%20163_zpsr5nnscb1.png) (http://s261.photobucket.com/user/john970s0/media/HARRISON/Grabbed%20Frame%20163_zpsr5nnscb1.png.html)

(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/Grabbed%20Frame%20165_zps3vimymu4.png) (http://s261.photobucket.com/user/john970s0/media/HARRISON/Grabbed%20Frame%20165_zps3vimymu4.png.html)

John
Title: Re: New Lathe
Post by: Ginger Nut on February 24, 2015, 10:55:27 PM
TV wise there are shows regarding all sorts like Antiques Roadshow, Bargain Hunt, Auction Hunters (USA), a few more.

Time we had a Machinists Show Scavenger Hunt staring John n Mick.
Title: Re: New Lathe
Post by: Stilldrillin on February 25, 2015, 04:46:17 AM
Time we had a Machinists Show Scavenger Hunt staring John n Mick.

 :thumbup:   :clap:  :clap:

David D
Title: Re: New Lathe
Post by: NormanV on February 25, 2015, 05:58:31 AM
"Time we had a Machinists Show Scavenger Hunt staring John n Mick."

No! Don't suggest it then everybody will be out there looking for bargains. It's bad enough that John and Mick are out there taking all the good stuff so that I can't find anything!

Let's just keep it a secret amongst ourselves.
Title: Re: New Lathe
Post by: micktoon on February 25, 2015, 06:36:31 AM
Hey don't blame everything on me and John ?................ What about Bob KRV3000 , he snatches his fair share of bargains  :thumbup: ................,  Then what about David , Bobs mate that went to two boot sales then found the muthaload me and John had spent 1000 hours searching for   :palm: , nice lad so we did not begrudge him the find lol as long as he keeps to the South of the River Tyne  :lol:

  Cheers Mick
Title: Re: New Lathe
Post by: Ginger Nut on February 25, 2015, 11:39:56 PM
Oooppps never thought of that.........then again I am 13000 miles away

Ah thanks Mick now I can get my relo's to search south side for me  :lol:
Title: Re: New Lathe
Post by: doubleboost on February 28, 2015, 02:54:18 PM
Lathe arrived safe & sound :drool: :drool: :drool:
Thanks to Stive at Landy Lift for a great job delivering it :bow: :bow:
Thanks also to Mick
The clean up is now well under way

(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340028_zpszhjx3pw9.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340028_zpszhjx3pw9.jpg.html)

(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340027_zpsfqj1vxjx.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340027_zpsfqj1vxjx.jpg.html)

(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340023_zpss2rgggy8.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340023_zpss2rgggy8.jpg.html)

(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340026_zpsrpjcp4p3.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340026_zpsrpjcp4p3.jpg.html)

(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340021_zps4qsqkfjd.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340021_zps4qsqkfjd.jpg.html)
(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340022_zps7rn02ued.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340022_zps7rn02ued.jpg.html)

(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340025_zpswah5xcdo.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340025_zpswah5xcdo.jpg.html)
(http://i261.photobucket.com/albums/ii63/john970s0/HARRISON/S1340024_zpsmonxydh0.jpg) (http://s261.photobucket.com/user/john970s0/media/HARRISON/S1340024_zpsmonxydh0.jpg.html)

John

Title: Re: New Lathe
Post by: RobWilson on February 28, 2015, 03:30:46 PM
Looking good  John  :thumbup:


Rob
Title: Re: New Lathe
Post by: Will_D on February 28, 2015, 03:52:29 PM
Are those the before or after shots John?
Either way she looks fantastic!

what has been fek'd out of the shop to make way? :bugeye:
Title: Re: New Lathe
Post by: hermetic on February 28, 2015, 03:58:21 PM
Hi John, Excellent news I bet you are chuffed! I also used steve from landylift to move my Covmac from Scarborough to Langtoft,  We had him for the day and ended up moving another three machines round the village! He is a good guy, and knows the moving game.
Phil
Title: Re: New Lathe
Post by: hermetic on February 28, 2015, 04:14:23 PM
OH NO!! John, the dials are in.....................foreign
(Just like my Harrison mill of the same era)
It was quite a shock the first time I went to use it, I had cleaned it, drained the coolant, cleaned it up, painted it (Green, alright look, Im sorry but it was already green and only needed touching up, and I would have preferred grey, but never mind) Put the vice on, set up a simple job (slotting a 1 1/2 BSP plug for a compressor cylinder head) Twas then I noticed ! Having never used a metric machine before, I was worried, but I speak a bit of French, and I thought, Damn you Napolean, how difficult can it be, and the answer is, not very! Congratulations John, It looks like it has hardly been used! Can't waid for the nightcap.
phil
Title: Re: New Lathe
Post by: awemawson on February 28, 2015, 06:27:33 PM
By 'eck John that looks reet nice  :thumbup:


If the mechanics live up to the paintwork you've landed yourself a really nice lathe there  :clap:
Title: Re: New Lathe
Post by: micktoon on February 28, 2015, 06:37:42 PM
 Hi John, glad to see the lathe safe and sound at your place. The lathe is as good as it looks mechanically wise too so a good bit of kit all round.
  Steve from Landylift was spot on too, knows his stuff with moving machines and nice fella to go with it. Let me know when you need a hand with moving stuff about for the final resting place   :thumbup:

  I bet you are thinking about re painting it green are you  :bugeye: :lol:

  Cheers Mick
Title: Re: New Lathe
Post by: Ginger Nut on February 28, 2015, 10:03:10 PM
 :mmr:

As does John and his new lathe, well done it looks like it was made for that spot. :thumbup:

I can see that the 4x6 bandsaw has been ousted but where too? Down the other shed  :Doh: you'll be kept fit n slim running backwards n forwards if that is the case. But what of the drill press?? Gas bottles??

Ok I have noticed you've had a garage door change as well no more panel lift but new roller door was that in prep for the Harrison arrival if so its been known for some time??

Clean as a new one. All those new tool rack to make.

How soon before we see John running the Boxford, mill and Harrison all in a SNNC all at once will he blow the fuse box?
Title: Re: New Lathe
Post by: Bigbadbugga on March 01, 2015, 08:52:20 AM

For some strange reason I just had a vision of john putting the two lathes tail stock to tail stock and bolting them together so he can turn longer shafts between centres.
Title: Re: New Lathe
Post by: Jonny on March 01, 2015, 02:19:21 PM

How soon before we see John running the Boxford, mill and Harrison all in a SNNC all at once will he blow the fuse box?

Used to run my old 140, mill on power feed and bandsaw. Newer lathe struggle to power lathe and same mill, either can trip fuse box.

Johnny looks like its recently ish been painted, saves you a job. Promise keep it grey.
Title: Re: New Lathe
Post by: dawesy on March 01, 2015, 02:27:43 PM
Very nice john. Looking very nice.
Seems to be in excellent condition.
Can't wait to see its snnc debut.
Title: Re: New Lathe
Post by: doubleboost on March 01, 2015, 02:36:10 PM

How soon before we see John running the Boxford, mill and Harrison all in a SNNC all at once will he blow the fuse box?

Used to run my old 140, mill on power feed and bandsaw. Newer lathe struggle to power lathe and same mill, either can trip fuse box.

Johnny looks like its recently ish been painted, saves you a job. Promise keep it grey.

Never been painted that is the original paint
John
Title: Re: New Lathe
Post by: Manxmodder on March 02, 2015, 12:28:22 AM
I can see from the photos that there ain't much wear on any of the slideways, and yer got the removable gap piece option as well. A rare find indeed, top banana,John. :ddb: :ddb:
Title: Re: New Lathe
Post by: Ginger Nut on March 02, 2015, 12:32:45 AM
John just watched the video sorry to hear about Deb hope she is ok and it goes well next week.

Top notch looking paint job too. Its been well cared for thats for sure if you find its just to much I'll gladly give you my address  :D

Nice to see some fast speeds on that its getting close to the speeds on my wood lathes 3000 rpm, the old Myford only does 750rpm.

Title: Re: New Lathe
Post by: Manxmodder on March 02, 2015, 12:39:39 AM
John, I have a question. Is that a detent type slip clutch on the leadscrew?  The one on mine is just a castellated dog clutch to disengage the leadscrew when not thread cutting.....OZ.
Title: Re: New Lathe
Post by: micktoon on March 02, 2015, 03:53:05 AM
Hi Oz , when I was at John's we were looking at the lead screw as mine sounds like yours with plain castllated nut, John's looks like there might be some sort of safety slip clutch in the nut ? But the rear of thevnut is still casttlated and can be disengauged.
  So it looks like its the same overall  idea but has a safety lutch built into the nut ?


  Cheers Mick
Title: Re: New Lathe
Post by: Manxmodder on March 02, 2015, 12:11:25 PM
Thanks Mick, it sounds like the idea there would be to set the bed stop at the point you want to stop the threading tool from advancing any further along the job. When the saddle hits the carriage stop the clutch detent slips and leadscrew feed is prevented from overunning the disengagement point .

 I guess its then a matter of disengaging the half nuts and returning the carriage to the pick up point of the next cut.

It looks an interesting and useful mechanism,hope John can give some greater detail of it's operation......OZ.
Title: Re: New Lathe
Post by: DavidA on March 02, 2015, 12:17:55 PM
   When the saddle hits the carriage stop the clutch slips  

 Wouldn't this throw your gearing out of sync and prevent the next cut from starting at the correct place ?

Dave.
Title: Re: New Lathe
Post by: Manxmodder on March 02, 2015, 01:42:05 PM
Dave, the clutch would need to be of the single engagement point detent type then it can only engage at the same point in any 360 degrees of rotation. Visualise the castellated type but only having one male and female tooth to understand the concept I'm thinking off.....OZ.
Title: Re: New Lathe
Post by: DavidA on March 02, 2015, 01:51:45 PM
Ah yes,  a dog clutch.  that makes sense.

I was thrown when you referred to the clutch slipping.

Dave.
Title: Re: New Lathe
Post by: DavidA on March 02, 2015, 07:00:44 PM
Thinking more about this.  There may be a snag.

I suspect that this dog clutch will only work when cutting threads that have a direct relationship with the number of threads on the lead screw. I.e. if you have an eight tpi lead screw it will work with 8, 16, 32, 64 tpi threads.
This is related to being able to 'drop in' the half nuts anywhere with 8 tpi lead  screw and the above mentioned threads, but the need to use a thread dial indicator for others.

I suspect, but not sure,  that it wont work if you were to, say, cut a 5 tpi thread with a 8 tpi leadscrew and then try to re engage the clutch of the chuck is not in the same position it was when the clutch dis engaged.

Readers views welcome.

Dave.
Title: Re: New Lathe
Post by: doubleboost on March 02, 2015, 07:16:57 PM
I think the "clutch" on the lead screw is there in case the lathe is "crashed"
Tool post crashes in to chuck lead screw slips to minimise damage
John
Title: Re: New Lathe
Post by: Manxmodder on March 02, 2015, 09:15:48 PM
Thinking more about this.  There may be a snag.

I suspect that this dog clutch will only work when cutting threads that have a direct relationship with the number of threads on the lead screw. I.e. if you have an eight tpi lead screw it will work with 8, 16, 32, 64 tpi threads.
This is related to being able to 'drop in' the half nuts anywhere with 8 tpi lead  screw and the above mentioned threads, but the need to use a thread dial indicator for others.

I suspect, but not sure,  that it wont work if you were to, say, cut a 5 tpi thread with a 8 tpi leadscrew and then try to re engage the clutch of the chuck is not in the same position it was when the clutch dis engaged.

Readers views welcome.

Dave.

Dave, a single point dog clutch will always re-engage the leadscrew at exactly the same relevant index as it was disengaged from and there will be no variation in the relationship of gear engagement because they haven't been disengaged or had their relative timing disrupted.

It doesn't make any difference to the repeatability of re-engagement if the dog clutch is located directly on the drive end of the leadscew(like the harrison lathes) or if it is located on the input end of the drive shaft for the screwcutting gearbox.

The reason it cant ever be engaged wrongly being that it has only 1 engagement/drive location in 360 degrees of rotation.

Similar single dog setups do exist,one example is shown and described fitted to a Myford lathe in Martin Cleave's book on screw cutting.

Title: Re: New Lathe
Post by: Manxmodder on March 02, 2015, 09:29:04 PM
Agree John, it being a safety device would make perfect sense considering the cock ups that some spotty Herberts in training college can make when inexperience gets the better of them.....OZ.
Title: Re: New Lathe
Post by: DavidA on March 03, 2015, 11:15:08 AM
...It doesn't make any difference to the repeatability of re-engagement if the dog clutch is located directly on the drive end of the leadscew(like the harrison lathes) or if it is located on the input end of the drive shaft for the screwcutting gearbox. ,

You are right ,  of course.
It would only make a difference if the gear train was disengaged between the leadscrew gear and the headstock gear.

Took me a while to clearly see the point; pun intended.

Dave. :hammer:
Title: Re: New Lathe
Post by: hopefuldave on March 06, 2015, 04:31:52 PM
I'm going to assume the half-nuts stay closed?

Quote:
...It doesn't make any difference to the repeatability of re-engagement if the dog clutch is located directly on the drive end of the leadscew(like the harrison lathes) or if it is located on the input end of the drive shaft for the screwcutting gearbox. ,

I'm going to disagree, lathes with single-tooth clutches (Holbrook, Hendey, Hardiinge, Pratt & Whitney - toolroom lathes) run them at spindle speed before driving the QCGB, not leadscrew speed after - at spindle speed it preserves the relationship between spindle and leadscrew (it can only engage once per spindle rotation so once per threading pitch as the half-nuts stay closed), a single-tooth clutch on the leadscrew can engage at any *leadscrew* pitch, with the spindle in an arbitrary position depending on the QCGB ratio, not the same thing! It MIGHT work for "native" threads, as suggested, as you'd effectively be opening the halfnuts and closing them on a random point on the leadscrew, definitely doesn't for anything else, e.g. metric on an Imperial lathe and vice-versa, which the spindle-speed dog clutch will do.

Another quote:
a single point dog clutch will always re-engage the leadscrew at exactly the same relevant index as it was disengaged from and there will be no variation in the relationship of gear engagement because they haven't been disengaged or had their relative timing disrupted.

Except that the spindle can rotate though an angle dictated by the QCGB setting and align the dog clutch without coming to the same angular relationship between spindle and leadscrew - e.g. for the 8tpi leadscrew, 11 tpi thread to cut, the spindle will have rotated 11/8ths of a turn (or multiples of) before it realigns the dogs. Assume the carriage is exactly where the dogs disengaged, the spindle will have rotated an extra 3/8ths of a turn and you'll be cutting a multi-start thread by accident...

I've looked into this a bit, as my lathe would very much like a single-tooth clutch, leadscrew/feedscrew reverse, threading stop and extra control rod, for cutting metric threads among others - added to the complication on my lathe, although the forward/reverse (R/H Vs L/H) selection runs at "spindle gear" speed is that the back-gear drives the spindle at 1/8th the speed of the "spindle gear" (on a concentric sleeve with its own bearings) that operates the QCGB etc. to get the "coarse" threads that really could use a threading stop disengaging a single-tooth clutch... Perfect if you need to cut 8-start 2tpi or 16mm pitch threads.  :palm:

Plans are being made, slowly, fitting it all in is challenging!  :bang:

There are a couple of single-tooth setups published, one is in Martin Cleeve's "screwcutting in the Lathe" (Workshop Practice series No.3), another in one of the model engineering magazines a couple of years ago, and all run the dog clutch at spindle speed to maintain synchronisation, there are versions for a good selection of hobby lathes.

Probably not what you want to hear, a leadscrew dog clutch would be MUCH simpler!
Title: Re: New Lathe
Post by: mattinker on March 06, 2015, 05:31:07 PM
If I remember correctly it's a metric lathe. Unlike the imperial lathe, the lead screw must be kept engaged as the dial thread indicator doesn't work for metric threads. I seem to remember reading somewhere that three different interchangeable D.T.I's would be needed for metric lead screws. I'd be interested in a dog clutch for my metric Emco compact 8! I'm jealous of your lathe John!

Regards, Matthew
Title: Re: New Lathe
Post by: Manxmodder on March 06, 2015, 06:18:01 PM
Dave,yes I forgot about the gears in the QCGB relative to the back gears etc if the clutch is located before the QCGB input shaft.

However,with my original idea it won't disrupt the synchronicity if the dog clutch is on the output side of the QCGB because it is simply disengaging the final drive line to the leadscrew in a manner that it can only re-engage at exactly the same single relative index to the final drive shaft output. With this arrangement no gears or half nut indexes have been altered at all....OZ.

Title: Re: New Lathe
Post by: Manxmodder on March 06, 2015, 06:26:04 PM
Matt, just for interest here is a metric thread indicator for a Harrison lathe. This would only be workable on a dedicated metric leadscrew and thread cutting gearbox...OZ.

LINK: http://www.ebay.co.uk/itm/Spare-Metric-Thread-Indicator-Dial-for-Harrison-Lathe-etc-Part-No-L16-4-14-/121264384998
Title: Re: New Lathe
Post by: hopefuldave on March 06, 2015, 06:55:26 PM
Hi Oz,

I have to disagree - only if the thread you're cutting is a multiple of your leadscrew pitch will it sync' up correctly by having a dog clutch on the leadscrew itself - believe me, over the last couple of years I've spent several  weeks in free time working on this! I've even spreadsheeted it and knocked up a lash-up physical model as my maths isn't so practiced nowadays, and it gives multi-start threads if you're not really, *incredibly*, EXTREMELY lucky (once in several tens for most threads, far more rarely for the oddballs like B.A., D.P. and module which have irrational numbers like Pi as factors) - the only way it works for ALL thread pitches is if the clutch runs at spindle speed! Honest!

This is probably why proper toolroom lathes run the dog clutch at spindle speed...

My solution (not yet built, CADded, simulated and appears to be likely to work, some of the commercial-off-the-shelf parts like gears and bearings already purchased) is using the existing forward/reverse selector but adding a single-tooth clutch with a sliding dog in place of a sliding gear pair (the gears with their dogs will be fixed and free on needle-rollers, the sliding dogs keyed to the shaft), and as I have to deal with the 8xspindle-speed drive to the screwcutting / feed geartrain, I've had to come up with a synchroniser very similar to those for the firing pin on machine guns back in WW1 which fired through the propellor without trimming its blades...

There's a VERY long thread on single-tooth clutches at
 http://www.model-engineer.co.uk/forums/postings.asp?th=49358&p=1
Where a lot of quite bright, practical engineers describe the mods necessary on a number of different lathes. It's worth reading, but everything in there is also in Martin Cleeve's book, if you dig a bit!

Matt, take a look at that thread - the principles apply to a lot of lathes (the Emco shares a lot of features with them) and could put you at square 3 or 4 rather than square 1?
Title: Re: New Lathe
Post by: hopefuldave on March 06, 2015, 07:04:50 PM
Oh, I almost forgot - Nice Harrisson, John! Didn't mean to hijack your thread!
Title: Re: New Lathe
Post by: doubleboost on March 06, 2015, 07:06:32 PM
No
Problem
carry on lol
John
Title: Re: New Lathe
Post by: hopefuldave on March 06, 2015, 07:33:08 PM
Some Proper Drawings of Graham Meek's very tidy design:

http://modelengineeringwebsite.com/Meek_screwcutting_clutch.html

And a description:

http://modelengineeringwebsite.com/Screw_cutting_clutch.html

Worth a read, if only to marvel at the ingenuity :)
Title: Re: New Lathe
Post by: mattinker on March 06, 2015, 08:03:18 PM

 http://www.model-engineer.co.uk/forums/postings.asp?th=49358&p=1
Where a lot of quite bright, practical engineers describe the mods necessary on a number of different lathes. It's worth reading, but everything in there is also in Martin Cleeve's book, if you dig a bit!

Matt, take a look at that thread - the principles apply to a lot of lathes (the Emco shares a lot of features with them) and could put you at square 3 or 4 rather than square 1?

Hopeful Dave,

Thanks for the link to the thread and the links to the drawing and description, stored away for later!

Regards, Matthew
Title: Re: New Lathe
Post by: RussellT on March 07, 2015, 03:11:04 AM
I'm not sure whether this will help, but if anyone is struggling to visualise why a single point leadscrew clutch won't synchronise for screw cutting then this example helped me.

Imagine a lathe with an 8tpi leadscrew.  The half nuts can be engaged every 1/8th of an inch along it's length and the single point leadscrew clutch can be engaged every 1/8 inch of carriage travel - even if the half nuts are left closed.

 If you're trying to cut a 1.5mm thread then it will only be right when 1.5mm is an exact multiple of the 8tpi thread.  In that example every that's every 7.5 inches along the lead screw.  (60 leadscrew threads and 127 1.5 mm threads).

Russell
Title: Re: New Lathe
Post by: Ginger Nut on March 07, 2015, 10:11:12 PM
Just thought will Mick be spending time teaching John how to use his new lathe? Will SNNC become J&MHC  :lol:
Title: Re: New Lathe
Post by: doubleboost on April 04, 2015, 03:34:27 PM
Harrison in its final resting place
DRO half installed
(http://i261.photobucket.com/albums/ii63/john970s0/S1380011_zps8fbktaeq.jpg) (http://s261.photobucket.com/user/john970s0/media/S1380011_zps8fbktaeq.jpg.html)
John
Title: Re: New Lathe
Post by: John Rudd on April 04, 2015, 03:39:05 PM
That really looks the part..... :drool:

I have lathe envy......especially after being round Rob's this morning, but this just tops it..

When we gonna see swarf?  :dremel:
Title: Re: New Lathe
Post by: Stilldrillin on April 04, 2015, 05:14:47 PM
Looking good, John!  :thumbup:

David D
Title: Re: New Lathe
Post by: Ginger Nut on April 04, 2015, 07:26:23 PM
Just watched video bet you were on your knees more than you are when you go to church John  :lol:

Looking good, the rear of the lathe looks like new.
Title: Re: New Lathe
Post by: dawesy on April 05, 2015, 02:01:41 AM
Very nice john. Really not had a lot of use that Harrison. Hope that changes
Title: Re: New Lathe
Post by: bertie_bassett on April 05, 2015, 07:03:25 AM
looks like a beauty ! 
Title: Re: New Lathe
Post by: vtsteam on April 05, 2015, 08:32:08 AM
It looks very nice, John. :thumbup: