Lathe

[éire man]

Hello lads, I've been looking on internet forums the past hour and all I can see is lads who haven't a clue!

Could ye please tell me if it's possible to cut M3.5 /M4 screws on a lathe as follows:
https://www.donedeal.ie/plantmachinery-for-sale/colchester-lathe/20706497

 

[TheTallGuy]

It looks like it has the metric/imperial change lever on the feed gearbox, but not all the standard metric pitches are available - especially the smaller ones.

http://www.lathes.co.uk/colchester/page4.html
http://www.stevenson-engineers.co.uk/files/_colchester_student.pdf

 

[davieh3350]

Hello lads, I've been looking on internet forums the past hour and all I can see is lads who haven't a clue!

Could ye please tell me if it's possible to cut M3.5 /M4 screws on a lathe as follows:
https://www.donedeal.ie/plantmachinery-for-sale/colchester-lathe/20706497

If it's not metric then you'll have a fair bit of calculating to get the back gears to turn the lead screw at the right ratio. Plus you would maybe need to buy some extra gears.
You'd be better just turning it to diameter and using a die to cut the thread at that size... So buy it!

a farming forum ain't really the place to ask though...

 

[pycoed]

Be much easier to use a die in a tailstock die holder to cut threads of that sort of size on any lathe larger than a clockmakers really.

 

[TheTallGuy]

Be much easier to use a die in a tailstock die holder to cut threads of that sort of size on any lathe larger than a clockmakers really.

It depends somewhat on the material & how long you need the thread or if there's features beyond the start of the thread. Also tricky if you need to use a centre for support.

 

[éire man]

Thanks for replies lads
What do ye think of the price
I haven't much use for tbh but I'd like to think she wouldn't depreciate at all

 

[2CE]

That's a Colchester Triumph. They come in two sizes (bed lengths) - the one in the pictures is a 30 inch, I have a 48 inch.

It will cut metric and imperial thread pitches, but it's a bit big for cutting anything as small as M3.5 / M4 - if you want to do small stuff like that you'd be better with a smaller model such as a Student or Bantam or an EMCO Maximat.

Price is about right if you compare with similar on e-Bay.

Lots more info. about them on Tony Griffith's site at www.lathes.co.uk.

Bear in mind that model is three phase and the motor is 5HP so trying to run it off a single phase supply with a converter would require a dedicated high current circuit.

 

[Kevm]

It's a Colchester master 11/2 very similar to mine, so it will do imperial and metric threads but I don't know if it will go as fine as 3.5mm thread (don't know the pitch and can't be arsed going down the workshop to look just now) but as others have already said it would be very fiddly screwcutting that size and far easier to use a die.
As to price/value they are worth a £1000 unless very rough, it looks like the tailstock is missing it's guts as I can't see a wheel or centre, so you will need to find one of those so knock his price down.
I run mine on three phase 240v, just a quick rewire in motor.
An excellent lathe check out this old tony on youtube - same lathe

 

[davidroberts30]

That is a small thread
Easy to screw it up

 

[davieh3350]

A bit of fence wire thick..

 

[Mursal]

When you say 3.5 - 4 is that not just the pitch of the thread, regardless of diameter?
That's usually the way you look at threads when your cutting them on a lathe.
0.6 x pitch for bolt thread depth
0.5 x pitch for nut thread depth
Both 60 degree cutting tool .....

Colchester make exceptional lathes, learned and did all my exams on them.
You'd need a bit of tooling with it if you can, but price is about right.

 

[Ley253]

You may be able to cut the required threads, but the screw cutting indicator may be no use. If this is so, you engage the lead screw once, leaving it engaged till the job is complete. Rapid tool withdrawal would be a great help here. Run the lathe in reverse to move the tool back to the starting point for each cut. If there is any length in the thread of this size, then a travelling steady would be essential, otherwise the job will at best be barrel shaped, or climb over the tool!

 

[davidroberts30]

When you say 3.5 - 4 is that not just the pitch of the thread, regardless of diameter?
That's usually the way you look at threads when your cutting them on a lathe.
0.6 x pitch for bolt thread depth
0.5 x pitch for nut thread depth
Both 60 degree cutting tool .....

Colchester make exceptional lathes, learned and did all my exams on them.
You'd need a bit of tooling with it if you can, but price is about right.

Op says cut m3.5 or m4 screws

 

[Mursal]

He does, just trying to make sense of it.

 

[Simmy]

Any thing less than m10 in a lathe will have a poor finish as you'll Need to be going fairly fast. There's no control. Anything that size we used to put in cnc if it was a batch. Any one offs just used a die

 

[tinman]

you wouldnt cut a thread that small on a lathe unless you were a model builder and if you are, your not going to do it on a lathe that size, there be tiny lathes for that job, of course you could if you wanted to but good luck with that.
just use a die or a tap to thread a hole that size.

 

[Scribus]

Hello lads, I've been looking on internet forums the past hour and all I can see is lads who haven't a clue!

Could ye please tell me if it's possible to cut M3.5 /M4 screws on a lathe as follows:
https://www.donedeal.ie/plantmachinery-for-sale/colchester-lathe/20706497

I was looking at that myself, never used a lathe but fancy trying my hand at it. Can anybody recommend how to go about picking up the basics seeing as there is nothing in the way of evening classes/course around here?

 

[Phil P]

I was looking at that myself, never used a lathe but fancy trying my hand at it. Can anybody recommend how to go about picking up the basics seeing as there is nothing in the way of evening classes/course around here?

YouTube is your friend for pretty much any machining task, someone will have done a tutorial on how to do it. Best to watch a few and practice on something that isn’t a critical part!

 

[DrWazzock]

You may be able to cut the required threads, but the screw cutting indicator may be no use. If this is so, you engage the lead screw once, leaving it engaged till the job is complete. Rapid tool withdrawal would be a great help here. Run the lathe in reverse to move the tool back to the starting point for each cut. If there is any length in the thread of this size, then a travelling steady would be essential, otherwise the job will at best be barrel shaped, or climb over the tool!

Leaving the lead screw engaged was a lesson I learned the hard way at college when we dabbled in turning work. Disengaged the lead screw each time. Got away with it twice then my final run peeled the thread right off leaving a tiny double thread in its place.

 

[tinman]

as phil says, you tube will be a good tutorial, loads of lads out there with videos of such.
this old tony iirc has basic enough tutorials on thread cutting, its a bit of an art so slowly slowly catchee monkey kind of thing.
pick up some alu and practice, practice, practice as they say, least its soft so if you make a mistake its not going to take everything with it.
Mr pete should have some good videos too.
joe pieczynski should have a few tutorials as well.

Tom here has a few videos which might help if your mad to go cutting threads but if you have little experience on a lathe, cutting a thread is certainly where i wouldn't start off but thats up to you.