lathe thread question

[turbo TA]

Hi everyone, I'm new here and I'm also new to working with lathes. I just picked up an old Atlas lathe and I'm slowly trying to figure it out. I love woodworking and metal working and I'd like to use the lathe to repair stuff or make things. What I'd like to know about making threads with a lathe (excuse my ignorance here) is why go through all the trouble when you can just put a threading die on the piece??? There is probably some machinist practicality that I'm missing. Thanks.

[pipeclay]

It would allways be best to turn the thread of anything on the lathe due to the fact that everything would be in the same axis.
Using a Die for smaller threads and non critical parts would be ok.
The cost of some dies would be very restrictive and also you would have a lot of expense catering for all sizes of dies to suit all the threads you cut,unless you limit your self to just a couple of diameters and maybe only one thread form.
And last but not least on the lathe you can virtually cut any thread form and on any diameter work piece.

[turbo TA]

Thanks,that makes sense,, i didnt think of it that way at all.
If anyone cares, I made a quick video of this lathe:
lathe video

[Dave J]

Nice old lathe, I did'nt know that some lathes could have long and cross feed going at the same time( learn somthing new every day).It would be quieter if you put a bit of oil or grease on the gears and also make them last a lot longer.
Dave

[turbo TA]

Hi Dave, that double moving cross slide feature looks like it is very tricky to set up. I'd like to see how its actually supposed to be used because I cant imagine it. Well, maybe if I disengage the half nut then the carriage will stay still and just the top will slide in or out. Either way ,its cool to watch them go back and forth on their own. :p
As for the noisy gears, when I got it they were covered in black grease and even noisier. I cleaned them up (maybe too good) and put oil on them, I was going by the manual, but I think I will find some sort of grease to put back on them.

edit:OOOPS !!! The manual says to put some sort of Keystone grease on it!! now to search for an equivalent.

[turbo TA]

Ok, I put some good gear lube on the gears.......BOY is it quiet now !!!!!!! thanks!

[Dave J]

The amount of gear mesh can also cause noise too.
If you look on this forum and over the internet you will find some good info on threading it will save you buying a lot of die's.I see your lathe already has a threading dial.
Have you made any chips on it yet? Be warned this hobby is addictive you will be wanting a mill next then a shaper then a ???.
You are lucky in that your in the US. things are so plentifull and cheaper over there compared to Australia.

Dave

[Woodlee]

Nice old lathe, I didn't know that some lathes could have long and cross feed going at the same time( learn something new every day)
Dave


Not something that I have ever seen either in all the years I've been associated with lathes .

Would make it very easy to have a serious crash I reckon.

Kev.

[turbo TA]

The amount of gear mesh can also cause noise too.
If you look on this forum and over the internet you will find some good info on threading it will save you buying a lot of die's.I see your lathe already has a threading dial.
Have you made any chips on it yet? Be warned this hobby is addictive you will be wanting a mill next then a shaper then a ???.
You are lucky in that your in the US. things are so plentifull and cheaper over there compared to Australia.

Dave
Hi Dave, no I havent really been on the lathe yet, I need a project and some scrap metal to practice on.

Woodlee - I dont think it is meant to have both cross feeds going at the same time, maybe one or the other....I have no clue.... but it does it. I have to check the manual and see what it says, but I did read something about the carriage making taper cuts. Maybe thats why ?

[pipeclay]

Not a common feature to find on smaller lathes but on some of the larger european machines I have used they have the feature built in to there Cross slide and Compound ,never used it as the Calculations required for the ratio between the 2 took longer to work out than cut the Taper.

[blackfrancis]

Is it because there is a power cross feed but no longitudinal feed? i.e. the lathe uses the screw cutting half nuts for the longitudinal feed. I believe the later model super 7's had a similar arrangement but don't know if they had an interlock on the feed.

The interlock is there so you can't engage longitudinal feed and screw cutting at the same time which would be a disaster. If you don't have longitudinal feed the problem's not there.

[Dave J]

blackfrancis
From looking at the video it looks like his lathe only has a screw cutting leadscrew and no seperate longitude feed shaft. Both the longitude feed and the cross feed run off the one screw cutting leadscrew so there is no chance of him engaging both shaft's as there is only one.
Dave

[blackfrancis]

Pretty much how I see it Dave. Except many lathes of that size and vintage have a leadscrew with a key down it that also serves as a feed shaft. For example the Hercus with power feed. On such lathes the longitudinal power feed usually moves the carriage at a different rate than the half nuts do. If you were able to engage them both at once it wouldn't be good :(

[Dave J]

I never knew that Hercus lathe's (or any lathe's for that matter) came with a keyway along the leadscrew. I would have thought that it would chop up the half nut's because it would act like a threading tap with the slot down it. My old Hercus I had years ago, did not have power feed seperate, it was only the powered by the half nut's, so this type of setup is new to me.
Out of curiosity I will do some research and have a look how they are set up.
As I already said earlier on in this topic ,"I learn somthing new every day."
Dave.

[turbo TA]

Hey guys,i just ran down to check the lathe,, there is a keyway slot all the way across the lead screw. I thought that was strange so I had to check. To the left is a lever that changes the direction of rotation of the lead screw - left, middle(no rotation, neutral ) and right. I dont understand all the parts but if you want me to put up pictures or check the owners manual for something, I will.