Install a Quick change gearbox on a Logan200 lathe

[ieezitin]

I have this Logan 200 lathe and its been very faithful to me for about 3 years now but I never got a set of change gears with it so threading and even using the gears for facing and turning I have never been able to do it, while researching via looking into buying the gears off ebay I established that it was some what cheaper to purchase a Quick Change Gearbox from a donor lathe that has been parted out and sold on the Flea-Bays.

This Model was never sold with a gearbox as standard from the factory, so installing one means I need to retro fit it and slice off around 11/32 of the Y-Axis that butts up to the lathe V-EE rail. My research tells me this measurement is somewhat suspect so I will take off an extra .040 and shim if I have too. This also means I need to slice up the lead screw to make it fit to make this project all Tickerty-boo.

I was severally beaten up on the price on The Flea-bays for the unit and I know I paid probably 25% over but!!!!!! This annoying problem I have had has plagued me so long  money is really not my concern and in the end who cares anyways so here goes.

This is the lathe that needs Modding



This is the unit somewhat set up on the mill. It’s an awkward piece to hold nothing is square other than the original machined L-Section  and the clamping forces are directed on the casting of the face of the unit, as shown I have supported it with jacks on the underneath of the milling cutter but the front is just resting on the mill table where it is suspect but I think it will hold.











I got my bearings by test indicating from the horizontal rise of the machined surface and the vertical, to get to a right angle I used a parallel and squared from the table with a machinist square, but always in my mind I knew it was not needed to get it dead-balls-on for square, The lead screw don’t care if its slightly racked! All that was really important was vertical and horizontal alignment, we can’t have the lead screw being pulled into-or away from the Half nut grab and the cross feed engagement being strained but like I said I am going to take off more meat so I can always add a shim. BTW the vertical plane of the gearbox equals the original height of the donor and receiver lathe, one less worry.














The reason for so many pictures of the setup is there has been so many inquiries about installing this Gearbox unit on this model lathe that allot of questions have been directed of the setup and even if this model can have a gearbox installed on it plus it gives a person insight how another person does his stuff.


Well thats all for tonight will post more soon.

All the best    Anthony.

[ieezitin]

Well
I milled off the 11/32 off the gearbox plus .030 extra, it was a little awkward getting a comfortable measurement from the side of the lathe rail and lead screw center so I just decided to over cut the whole thing and shim plus this allows me a little wiggle room in setting the centers to rune true.

With the lead screw and lead screw bearing housing dismantled from the lathe I offered up the Gear-box to the lathe rail. I then had to locate it so the banjo will line up with the gearing, I did this all by eye as being a little off would not hurt but in fact it turned out Dead-balls-on.













After drilling and tapping 5/16 NC I installed the box. The lead screw is now too long as in its original form it penetrated through a bearing housing which contained a hub where the Banjo sits on, so now I have to shorten it so it slides through the gear-box and terminates just before it hits the gear train, I got this measurement while the box was in place.


I had to turn down a small spigot at the end of the lead screw for the drive gear to be installed, ¾ down to ½ by about 4” long. This measurement was important because the original OD of ¾” fits into an Oilite  bush in the gearbox
Here I am turning down the lead screw on the lathe that’s getting the Gear-box








The drive gear that transfers the gearing from the gear-box has been installed, it’s a ½” bore with a .125 round woodruff key seat. This fit needs to be smooth and easily removed because you have to install the lead screw through the Gear-box and as it just pokes through you have to slide the gear on and seat it in the key, it’s a little tricky, when the gear is seated it cannot come out because it held in place by the gear it mates with in the gear train.That piece you see on the vice is the leftover from the chopped up lead screw









Here it is now all installed in the Gear-box and is ready for install.






All done for now will continue soon

Thank you for looking.    Anthony.

[andyf]

Looks a very nice job, Anthony. You certainly go in for some interesting setting-up operations!

I'm sure it will work as well as it looks; wish I had a quick change box.

Andy

[ieezitin]

Peoples

My first project for a piece made with the help of the gearbox was a threaded boss that fits onto a plate for my rotary table. My spindle nose thread is 1-1/2-8TPI

Now i can take work that's in the chuck on the lathe off and install it onto the milling machine without disturbing the hold.





In a hurry I did not pay attention while i was making this and i used a piece of scrap stainless i found laying around, when it came for the choice of the fixing screws it was dictated by the head size, after measuring what i had  i found i ran out of room around the boss for choosing any decent size screws, you have no choice but to sink the heads into the boss as the back plate of the chucks seat on this boss, i ended up with 6-32  so i stuck six in and for strength i installed a #2 taper pin.










Its all done and dusted. I am very happy with what i have achieved, the money i invested was well spent.  Thanks for looking.   Anthony   

[Noitoen]

That's cool keep up the good work 

[Meldonmech]

     That is a brilliant result for what was a very challenging project. I have fitted a Norton box to a Raglan 5inch which turned out to be a much bigger job than I expected. The rewards come when you cut your first threads as you have discovered.

                                                       Well Done   David