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Turning long and thin rod

Corn

Aluminum
Joined
Nov 3, 2019
Hi,

I need to turn fairly long and thin bar. I’m thinking how should that be done. Finished product is mostly 8mm thick and 150mm long. However there is one shoulder with diameter of 11mm. If I were to make it from 11mm stock what might be the correct way of turning this? Some sort of steady rest which would be the opposite side of the cutting tool would be good but I only have huuuuge rest which doesn’t suit into this purpose.

I was thinking of two options. Have that 11mm shoulder machined separately then press fit it afterwards. Then it could be made from 8mm stock. Or machine short distance at a time and then move that part out from the jaws and continue another distance. Neither of those sounds very good, but is there any other choice?

Thank you in advance
 
Collet, turn short distance, advance, repeat.

Flip end for end and finish the head.

If you need to, add a few m.m. to the skinny end and drill a center and use a live center.

Easy peasy.

PS, the steady rest will only get in the way.
 
swiss machining, stick out, turn it, then stick out some more and turn some more
.
swiss lathes do this automatically some how, on a manual lathe you manually do it
 
I think Thunderjet is optimistic. On a skinny piece like that machine a bit, stick out a bit further and machine more pretty much guarantees that it will climb over the tool and go prestzel before you have finished. Even with teeny weeny cuts and a centre.

As Limy says classic reason why roller boxes were invented.

If you have a four way tool post or a QC system capable of mounting more than one tool without the carriers or shanks interfering a poor boys substitute for a roller box is an L plate style steady on a suitable shank held just behind the cutting tool. Not as strong as a proper roller box unless you go more serious on the engineering than a one time job is worth but it will get the job done. In two cuts rather than one. Or, if you don't have to get over that collaer mid cut, you could use a right size bush which probably will get the job done in one cut if well lubricated.

Clive
 
150mm long is only 6"... I'd think you could just stick it halfway in the chuck and turn half, then turn it around and turn the other half easy peasy. Not THAT bad of a L to D ratio if you do it half and half and use a good sharp tool with a very small nose radius. Could actually probably do it in one shot unsupported.
 
If you can get away with a two piece I'd just drill an 8mm hole in the 11mm stock and insert the 8mm bar in to it. You can do a heat/cool fit, Loctite retaining fluid, pin it, etc. No messing around with trying to get a long thin bar on the lathe.

JMHO

-Ron
 
I agree. If a press fit head is permitted why even bother trying to turn it? Order TGP 8mm shaft, machine the head, press it on, call Bob your Uncle to finish it.
 
use a roller box, - like this YouTube

Exactly the sort of job a box tool's made for

That's pretty cool, but I'm boycotting them. Twice they mention that it's marketed toward engineers.:nutter:
What the fuck do engineers know about machining? At least 99% of them anyways.
 
That's pretty cool, but I'm boycotting them. Twice they mention that it's marketed toward engineers.:nutter:
What the fuck do engineers know about machining? At least 99% of them anyways.

Ah/ that is more to do with translation, in the USA and on the tools guy on the shop floor is a machinist, the guy at the drawing board the engineer.
In the UK the guy getting his hand dirty is often called an engineer, the guy on the drawing board a draftsman or designer.


So when tangi Flow say it's marketed towaeds engineers, they mean the guys actually using the tool

Confusing isn't it.

Oh and boycott who you like ;)
 
Ah/ that is more to do with translation, in the USA and on the tools guy on the shop floor is a machinist, the guy at the drawing board the engineer.
In the UK the guy getting his hand dirty is often called an engineer, the guy on the drawing board a draftsman or designer.


So when tangi Flow say it's marketed towaeds engineers, they mean the guys actually using the tool

Confusing isn't it.

Oh and boycott who you like ;)

Or the one blowing the whistle on the loco....
 
That's pretty cool, but I'm boycotting them. Twice they mention that it's marketed toward engineers.:nutter:
What the fuck do engineers know about machining? At least 99% of them anyways.

Rutt - Roh

Limy better explain the term "bespoke" as well.....
 
swiss machining, stick out, turn it, then stick out some more and turn some more
.
swiss lathes do this automatically some how, on a manual lathe you manually do it

Swiss lathes do it like this, Tom:

M3S1=3500
G98 G0 Z-.01 X.3149
G1 Z5.118 F.002
X.43307
Z5.9055
U.05W.05

Slightly less than a minute per part (depending on material, could be faster, could be slower)

of course, in real life, I'd have the sub spindle come support the finished diameter, this was just a basic example.
 








 
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