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Standard Modern 1340 lathe question

boomerang69

Aluminum
Joined
Sep 26, 2009
Location
virginia,usa
Good morning folks,I have a question about my standard modern lathe,I hope its okay to ask it here.My machine has a leadscrew and feed rod.Both turn when using feed on carriage.I was wondering if there is a way to disable the leadscrew when I,m only turning using the feed.This machine is probably 40 years old,it was in my high school metal trades class 33 years ago.Its kinda nice to have being one of the first lathes I used.It would be alot quieter if I could disable this when feeding.The serial number is 9288 if that helps.
Thanks Rick
 
Don't know about your lathe in particular, but usually you just disengage the threading on the headstock.
 
I have the same lathe and as far as I know the lead screw and feed rod are inter connected in the feed box so running one and not the other is not possible. If you want to disengage the feed box completely there is a neutral position on the feed direction control knob. Turning the knob so the arrow points up is the neutral position and will stop the lead screw and feed rod. My guess is that you already know this.

If your gear box is making an excessive amount of noise it may be because it is set to feed the course threads. There is a feed knob on the outboard side of the headstock just below the spindle. If the knob is pulled out it is set to cut 14 TPI or courser. If it is pushed in it will be set to cut finer then 14TPI plus your normal feed rates for turning. If the feed selector knob is pulled out the gear box will really sing to you especially when you get to about 1000 RPMs. I don't know how familiar you are with this lathe so all of this might already be known to you.
 
I think you are probably out of luck.

The feed uses the same gear train off the headstock (inside the LH end door) to transfer power from the headstock to the gearbox which runs the leadscrew and the feed rod. Note that the direction knob controls both.

I think. Been a fair few years since I ran one.
 
Don't know about your lathe in particular, but usually you just disengage the threading on the headstock.
I believe he wants the feed shaft to continue turning so he can continue doing auto-feed (either cross or longitude) but stop the lead-screw that would be used for threading.
i hope these pics load
I see them fine.

Unfortunately, I don't see a way to disengage the lead-screw without also shutting off the feed-shaft. If there were a way it should be right there on the quick-change box. On my LeBlond Dual Drive there is a lever that just gets thrown between "FEED" and "THREAD". I believe there is also a neutral position on one of the 4 control levers to shut it all off.
 
thanks for the replies,I checked out some youtube videos and all that showed them running,the leadscrew was turning.Its not that big of a deal just when you change over to the course feed it gets a bit loud.I also thought if it could be disengaged it would save a little wear.Its been like it is this long i'll quit bitchen.Thanks again
 
Thanks for your reply guncrank,in the picture of the leadscrew I thought it looked like a repair where the shear pin is.I see on some of the others I looked at it looks the same.This came from the local high school,you never know if it was damaged and patched up.
 
Thanks for your reply guncrank,in the picture of the leadscrew I thought it looked like a repair where the shear pin is.I see on some of the others I looked at it looks the same.This came from the local high school,you never know if it was damaged and patched up.

Yeah I noticed that. I bought mine from a used machinery dealer so I have no idea of its history. Mine came with a roll pin in place of the shear pin. I have not bothered to change it in the 15+ years that I have used it.
 
I have quite a few lathes and over the years had many of the top brands. Simply put those lathes that change feed and lead screw connection do it after the quick change box. The quick change box is used to change both feed and lead screw rate. So if the gearbox is noisy and the lead screw was disconnected you will still get the noise. Only lathes I had or seen were old flat belt lathes that had a belt to run the feed. On those you could have one, the other or both. Probably why it's noisy is due to what looks like a repair. Someone could have crashed while threading.
 
Yeah I noticed that. I bought mine from a used machinery dealer so I have no idea of its history. Mine came with a roll pin in place of the shear pin. I have not bothered to change it in the 15+ years that I have used it.

You might consider changing the roll pin to a piece of aluminum welding rod. I've accidentally crashed my 13X40 lathe now and then. The aluminum rod always shears with no damages. Had there been a roll pin, I'm sure that there would have been some broken gears.

The aluminum rods that came as spares with my lathe were two mm. I use 1/8" aluminum welding rod scraped and sanded down to fit.

Just a suggestion. It could save you a lot of trouble.
 








 
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