Author Topic: Help needed with my lathe  (Read 10966 times)

Offline ieezitin

  • Hero Member
  • *****
  • Posts: 662
Help needed with my lathe
« on: December 25, 2010, 02:13:22 PM »
Hello peoples

I have a Logan 200 10” swing lathe and I was wondering if anyone has fitted a quick change gearbox to there’s, this unit was made not to accept a gear box to it, the model 820 (same size as mine)  came from the factory with a quick change gear supplied, and I know Logan made many interchangeable parts,  I am assuming the lead screw would be the same size on both machines.
On the model 820 the gearbox is bolted through to the bed rails located underneath the headstock, my main concern is drilling through the rails and tapping it, all ideas and advice would be welcomed.

I do not have the change gears so I face a cost in the future, a full set of gears costs 2/3 of the cost of a quick change gear box, so I would rather put effort and spend a little more money and get a better value for all my input.

I have never modified any of my machines where it involves altering the main structure for good where there’s no turning back so I am a little hesitant about it but I am more than willing to give it a try as the payoff is large.

Again all ideas and advice is would be highly appreciated.  Thanks in advance  Anthony.


If you cant fix it, get another hobby.

Offline 75Plus

  • Hero Member
  • *****
  • Posts: 624
  • Country: us
Re: Help needed with my lathe
« Reply #1 on: December 25, 2010, 02:27:18 PM »
Anthony, Logan is still in business as Logan Actuator Company. They still make parts for Logan Lathes and Wards Lathes.
 
This is the link to their site.  http://www.loganact.com/  The FAQ section also has a lot of info. http://www.lathe.com/faq/index.html

They can answer all your questions.

Joe
« Last Edit: December 25, 2010, 02:33:17 PM by 75Plus »

Offline Bogstandard

  • Bogs Group
  • Hero Member
  • *****
  • Posts: 1107
Re: Help needed with my lathe
« Reply #2 on: December 25, 2010, 03:44:46 PM »
Anthony,

Although I have never done one myself, but I have known other people who have fitted gearboxes to their lathes, but not the Logan. But almost anything is possible.

It always helps if you have someone with a shop to fall back on while you are modding yours. Maybe you will need to machine mounting points and recesses into the main frame, and you can also guarantee that the leadscrew will require modifying, machining up on the end so that it is maybe shorter, and so that it fits into the end of the new gearbox. Having your lathe in a catch 22 position, where you need a lathe to do the machining, but the lathe is stripped down for the mods doesn't help.

Planning well ahead can solve most of your problems, especially if you can get someone to measure up for you their machine, that has a gearbox already fitted.


Best of luck with your venture.


Bogs
If you don't try it, you will never know if you can do it.

Location - Crewe, Cheshire

Skype - bandit175

Offline ieezitin

  • Hero Member
  • *****
  • Posts: 662
Re: Help needed with my lathe
« Reply #3 on: December 25, 2010, 04:56:25 PM »
75.
Thanks for the link,  I was quite impressed with the fact the company is still going and is very responsive to helping people who own their machines from way back like myself, they still manufacture and sell parts going back 60 years, I read the history and that was very interesting , more than that it seems the present owner is very involved in helping people like me.

I read that a 820 series qc will or can be fitted to my 200 by milling 11/32 off to align to the center of  the lead screw, that’s no problem at least I know it’s possible and has been done.

John.
Good advice, I have another lathe in my inventory so I plan that machine to help me through whatever I need, agreed and understood that the lead screw needs to be snubbed .  so far what I see I will need to drill and tap into the bed, maybe you or anyone else could let me know what I may be in for in this procedure,  I was thinking of making a jig that clamped to the rail so the drill drove in square at the same time this would true the tap.  Not having reworked lathe beds before any advice of tapping sizes % wise, or do I treat it just like cast iron, like I said it’s a onetime deal  and I want to get it right.

Like John has mentioned if anyone has done this before on this machine I would love to hear from you. Thanks all.             Anthony
If you cant fix it, get another hobby.

Offline Bernd

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 3688
  • Country: us
  • 1915 C Cab
    • Kingstone Model Works
Re: Help needed with my lathe
« Reply #4 on: December 25, 2010, 05:04:17 PM »
Anthony,

If I'm not mistaken you would need a shorter lead screw also. Unless that lead screw is in two parts on your lathe.

I have a 1875 10" and love it.

Bernd
Route of the Black Diamonds

Offline John Hill

  • The Artful Bodger
  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 2016
  • Country: nz
Re: Help needed with my lathe
« Reply #5 on: December 26, 2010, 02:38:17 AM »
Sounds like a golden opportunity to build an 'electronic leadscrew'!
From the den of The Artful Bodger

Offline Bogstandard

  • Bogs Group
  • Hero Member
  • *****
  • Posts: 1107
Re: Help needed with my lathe
« Reply #6 on: December 26, 2010, 04:18:15 AM »
Anthony,

Of all the lathes I have come across and had to machine, they all went fairly smoothly. The metal is usually easily machined cast iron, and that can usually be worked on with hand tools, electric drills etc, that saves on trying to get the bed onto a machine for drilling. That is of course if you don't need reccesses and things cutting out, but again, depending how adept you are at drilling and filing, even that can be done accurately by hand, and a cheapo die grinder helps a lot in that department.

For marking out such things, I have a large collection of transfer punches. Get someone to help hold the part in position, then feed the punch thru a hole and give the end a tap. That puts the punch mark for drilling your first hole. Drill and tap the hole and mount the part up, making sure it is in the correct position, then repeat with a transfer punch for all the other holes. I find I can get things spot on that way, easily within a couple of thou. I mounted my DRO read heads by doing it that way, and when checked out with a DTI, they were spot on. You always have a bit of fiddle factor anyway, the bolts usually have a bit of play in the holes they go thru.

It is very difficult giving advice like this because at this time, it has to be just general stuff. When you actually get the job in hand, then by looking at it, more accurate information can be forthcoming.

Like I tell most people, if you get stuck, and you can get the part to me and aren't in too much of a rush, I don't mind helping out. There is always something in my shop requiring machining or fixing that isn't mine.


John
If you don't try it, you will never know if you can do it.

Location - Crewe, Cheshire

Skype - bandit175

Offline Jonny

  • Hero Member
  • *****
  • Posts: 780
Re: Help needed with my lathe
« Reply #7 on: December 29, 2010, 05:13:08 PM »
Sounds like a golden opportunity to build an 'electronic leadscrew'!

Tell me more, could be quite interesting for those without gearboxes.

Know what you mean Bogs just put a 720mm lg scale on X axis armed with drill, centre punch and DTI. The covers and scales are not that accurate from an extrusion but settled on 1 1/2 thou and nil runout on the side just bolting on, couldnt believe it. Y is even better with miniature magnetic type.

Offline ieezitin

  • Hero Member
  • *****
  • Posts: 662
Re: Help needed with my lathe
« Reply #8 on: December 31, 2010, 12:38:22 PM »
Hello.

Well I got the information I needed, I joined the Logan group on Yahoo (nice bunch of friendly fellas on there ) and posed the same question on that board,  the consensus is that it’s just a matter of milling down the casting of a Logan qc box of a donor 820 model  by .341 to make the center of the lead screw match the center of the qc box, because the 200 model was not intended for a qc the 200 saddle gearing is different to a 820 model  this has a clutch design, to match the spindle speed with lead screw feed a new gear train needs to be set up.

One excellent suggestion from a chap on that board was to install a 820 saddle  making it a model 200 / 820, so those are my options to ponder. I will attempt this and would like to have it done in two months, when I get into it I will start a build log.

John Hill, I am also intrigued on an electronic lead screw and what it involves and advantages it may have, if you could supply detailed information  I would like to review it as if it’s a better way than what I will be attempting to do I surely would give it ago.

Anthony
If you cant fix it, get another hobby.