Coolest thing I've ever done on a lathe

#1
A friend of mine has a small HF combo mill lathe machine. He uses it at his work for odd jobs. The other day he called asking for help, the brass bush that engages onto the feed screw of his machine had stripped from years of use. " I know years of use :laugh: , but its true 5 years old"
All the new models have a different pitch and no spares available.

At Christmas I upgraded my little lathe to the 750w 500 centers screw cutting lathe.

First problem was mine did not come with a full set of gears, at least the trip to my HF payed off they had a damaged one in the store and let me help myself to all the gears I wanted.

The thread we had to cut was a reverse Acme with a 15mm bore.
We used a shaft from one of Mikes old machines, then drilled a 6mm hole through the bottom of it. then we inserted a 6mm round piece of HHS stock and ground a point to match the lead-screw he had taken off the machine.

First pic with the vernier was me testing to see if we could get a 4mm pitch with the gears we had.

Then we tested the cutter on a piece of 40mm nylon just to make sure we had everything set up right.
Sorry no pics of that wasn't planning a share.

Then we switched over to brass, the old bush is actually a half of the turned part so it would need to be split later.
We sent the wives of to 50 shades of Gray and then spent 2 hours turning up the bush.



Its slow going because of the pitch you have to run at a slow speed - you think you're going to loose your mind trying to remember the order of steps :laugh: Engage thread at number 1, cut through bush, disengage the feed , turn in cross slide, turn out cutter, reset cross slide, turn out compound slide and then start all over .

Any way Mike sent me two pics today, he finally split the bush and checked it against the lead screw, Man was I stoked to see those pics. Just a quick share on the coolest thing I've done on a lathe



 
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#5
those "dogs" wear out when people use them for "auto feed". That is supposed to be used for threading only so it keeps its tight tolerance and lasts.
nice job saving his old lathe.
 
#7
those "dogs" wear out when people use them for "auto feed". That is supposed to be used for threading only so it keeps its tight tolerance and lasts.
nice job saving his old lathe.
There are a lot of lathes, especially older lathes and econo lathes that use the lead screw and half nuts for threading and auto feed. They have no longitudinal clutch feed.
 
#9
There are a lot of lathes, especially older lathes and econo lathes that use the lead screw and half nuts for threading and auto feed. They have no longitudal clutch feed.
I know, lots out there like that, but they were never sold as auto feed, they are for threading, I know tons of people (my buddy for one) use them for feed but it just isnt correct. Yes it works to an extent and the parts wear out and you can just replace them, but was saying, it is not correct. I have a 1945 lathe that has clutch auto feed, the technology was there, just not available on all lathes.
 
#10
I know, lots out there like that, but they were never sold as auto feed, they are for threading, I know tons of people (my buddy for one) use them for feed but it just isnt correct. Yes it works to an extent and the parts wear out and you can just replace them, but was saying, it is not correct. I have a 1945 lathe that has clutch auto feed, the technology was there, just not available on all lathes.
I'm not saying it's the ideal way to accomplish power feed, it obviously will cause premature wear to the half nuts and lead screw. Any lathe equipped with a separate feed rod and friction clutch should be used as designed.

But to say "they were never sold as auto feed" is simply not true...sorry but you're wrong.
 
#11
South Bend Model C or 10K





South Bend didn't make junk..this was considered a precision machine. It was simply made more economically for the small shop owner or home machinist. They made thousands of them.

I have this 1940's era Logan 9" lathe in my basement. It is also designed to run the power feed off of the lead screw. There's a brass chart riveted right to the machine with the various feed rates obtained using the loose change gears.

I've been using it this way for 20 years...nothing has worn out on it, but I don't abuse it either.



I've never used one, but I'm going to guess the Harbor Freight lathe that Tank fixed only has a lead screw and half nuts for longitudinal feed.
 
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#12
news to me for sure, I was always taught that was a romper room no-no, but the ad for the bench type hobby machine does indeed say it is so, for that one. maybe its simply marketing to a cheaper market with them saying "you dont need that clutch drive thingy, its all good with the clamshell here".
the brass tag should be gear changes for feed rates required for various threads per inch etc etc, The ad is the first one I have ever seen saying use it as such.
 
#13
Hey Uncle Gerry,

This is a pic of the machine my friend has. Its a catch 22 situation, the handle on the right and the bush we made are used to move the slide in milling mode. Basically they clamp a vice where the tool post is, from years of cutting it just wore out. He tends to do more milling than turning.

 
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