Threading on a 100 Year Old Lathe

Before the invention of the threading dial, cutting threads on a lathe was a bother. After engaging the threading lever on the carriage, you make one cutting pass, stopped the lathe, ran it in reverse to wind the carriage back to the beginning, stopped the lathe again, reversed direction again, then made the next cut. You Never disengaged the threading half-nuts or the threads you were trying to cut would be ruined.

On modern lathes with a threading dial, you can disengage the half-nuts and move the carriage back without stopping the lathe at the end of each cut. Much faster!

We used the 100 year old Rahn-Larmon lathe because the spindle bore was big enough to put the the 1-1/8" acme rod in it, unlike the smaller lathe I have access to. We had to cut 7/8"-9 threads on the end of the rod.

Category:

Education

Tags:

• metal
• lathe
• threading

[Steamin1000]

@tonytiger75 - Thanks for the tip about cutting threads without a threading dial - your video explained it well and it is a simple technique I will use in the future!

[FactoryDragon87]

OH WOW!!! First time I see that to belt-drive lathe can cut threads! You have great skill experiece on this lathe. This lathe original engine is steam engine???

I too have old lathe- it is build before WW2 and it make by "Gustloff Werke"... only it need repair for work. (The "Gustoff Werke" lathe kinematics is very close at Russian stanko 1A625)

[Steamin1000]

@FactoryDragon87 Maybe the original engine was steam, maybe not. Before electric motors became small enough and affordable so each machine could have its own, it was not uncommon for shops to have a main lineshaft driven by a single, large, electric motor. All of the equiment like this lathe would be connected to the smaller jackshaft like I have and the jackshaft would get its power from the big lineshaft. Best of luck with your lathe!

[toadabc]

It looks like you are in a hobby shop, but do you have a line drive on your ceiling? If so, please show some pictures. I just got an old lathe that looks like yours, but I can't find a name on mine. What brand is yours, and where was the name plate located? Thanks

[Steamin1000]

@toadabc I was lucky that the brass name tag was still attached and readable on the headstock, otherwise I would have no idea who made it. To help identify your lathe, I recommend this really great website forum "Antique Machinery and History" at the practicalmachinist .Post pictures with a "Mystery Lathe" question and I'll bet they ID it in less than two days. And provide great advice on overhead lineshaft mounting and powering your lathe.

[Steamin1000]

@toadabc I was lucky that the brass name tag was still attached and readable on the headstock, otherwise I would have no idea who made it. To help identify your lathe, I recommend this really great website forum "Antique Machinery and History" at the practicalmachinist dit com Post pictures with a "Mystery Lathe" question and I'll bet they ID it in less than two days. And provide great advice on overhead lineshaft mounting and powering your lathe.

[pheenix42]

The nifty thing about machines like this...the only computer control is in the machinist's head!  =D

[GaryBearful]

Very nice demonstration. I own both a 1912 South-Bend C model 11" lathe and a pre-1910 American Tool Works lathe. The American is a full featured lathe, with a quick change, adjustable feed, power cross-feed, telescopic cross feed screw, the works. Its funny, but with all these features, there's no threading dial!

The engaged reversing method you've shown is a good idea and probably a lot easier than chuck marking and all. Very nice. 

[nitehite1]

i think this is incredible this machine must be 14 or 16 inch leblond i have one a little newer it still uses a flat belt 3 speed transmission with reverse clutch and flywheel and v belt to i think is a 5hp electric motor i love it simple easy to use great for any need! but old and slow it s just great!

[tonytiger75]

It also works easier for course threads that fine threads, I always end up stoping the lathe and turning it by hand to realign for fine threads, it might help if I geared things down a little slower. Oh and I always set a stop on the bed instead of using a mark for the carriage, the mark always goes away when oil gets on it.

[tonytiger75]

It takes some getting used to, the setup is maybe not so clear in my video. You engage everything first, gear train and half nuts with the cutter a safe distance from the work. Then pull through the cone pully by hand till all the lash in the gears is taken up. Make the mark on chuck, screw gear and one on the bed by the carriage.you need to come back to that same spot,

[tonytiger75]

I have a lathe just as old as yours tough not as large, I never back up the lathe for another pass at a thread. I have a video demonstrating the method... it's been around for ages.

I basically operate at the same speed as a modern lathe without all the fancy gadgets.

I recognized your setup from practical machinist, then I see the previous comment... I knew it looked familiar! :)

[trespire]

What a beautiful machine, looks in good condition as well. It has that "well engineered" look to it. If looked after, it will probably be in good fettle in another century.