Turing very small shafts

[SmithDoor]

Most use a follower rest but most only goes down to 3/16" [3.5mm] aBIX TOOL WILL GO DOWN TO Wtch

A small box goes down to watch size here article on roller box and box tools works in tailstock too

Small box tools
Here’s a couple box tools I made to use with my little bed and tailstock lathe turrets for taking deeper and more accurate cuts off the diameter than with regular knee tools on relatively long and thin workpieces.

They’re basically copie9d from pictures of existing designs, mostly Levin and Somma.


Like on those the cutter is held more or less tangential to the work, opposite two adjustable supports set back a little to bear against newly cut surfaces. The larger of the two uses hardened rollers in screw adjustable blocks that are held in with dovetails, while the smaller one uses toolbits ground at opposing angles. Both have floating shanks, partly so I can replace them with others for different applications.

They work okay - they’re kind of hard to adjust but that may be just me.


The smaller tool is about 1-1/2” x 15/16” - it uses a 3/16” cutter and 1/8” back rests, and will pass up to about 1/4” work through the body. The bigger one is about 2” x 1-1/4”, uses a 1/4” cutter and passes 5/16”. Both have the tools tilted with 7° side cutting angle as well as front and side clearance, and use 40tpi adjusting screws

 

[timo_gross]

Is there a risk, that soft steel becomes a cork screw if a long piece is driven from the chuck end? I ruined some dies, when trying to thread the end of a skinny soft rod.
Does a Swiss lathe re-chuck the work on the driven side?

I had to make a long skinny piece a while ago, so I purchased a follow rest. (which was collecting dust since then).
You gave me some idea, i do not need a thin piece right now. But I am trying new tricks all the time.
I replaced one tip of the follow rest with a piece of hex bar stock. (could have paid more attention to the alignment). I chucked a center drill in my collet holder and just drilled "into the follow rest".
Then drilled and reamed the hole 3 mm (smalles rod I had at hand).

It is quite weird to use. Is it a "poor mans swiss lathe"?


Outcome was a long 1.5 mm pin made from 3 mm "bar stock" in one pass. I guess with some extra fine cutting tool it can be further perfected.



Greetings Timo

 

[SmithDoor]

Is there a risk, that soft steel becomes a cork screw if a long piece is driven from the chuck end? I ruined some dies, when trying to thread the end of a skinny soft rod.
Does a Swiss lathe re-chuck the work on the driven side?

I had to make a long skinny piece a while ago, so I purchased a follow rest. (which was collecting dust since then).
You gave me some idea, i do not need a thin piece right now. But I am trying new tricks all the time.
I replaced one tip of the follow rest with a piece of hex bar stock. (could have paid more attention to the alignment). I chucked a center drill in my collet holder and just drilled "into the follow rest". View attachment 165928
Then drilled and reamed the hole 3 mm (smalles rod I had at hand).

It is quite weird to use. Is it a "poor mans swiss lathe"?
View attachment 165929

Outcome was a long 1.5 mm pin made from 3 mm "bar stock" in one pass. I guess with some extra fine cutting tool it can be further perfected.

View attachment 165930

Greetings Timo

I only used roller box on engines lathe , turret lathes and screw machines. Never had a cork screw

Dave

 

[Charles Lamont]

Running down a long thin rod at high speed using a bush steady, the unsupported outboard end can whip if it is gets too long.

 

[SmithDoor]

Running down a long thin rod at high speed using a bush steady, the unsupported outboard end can whip if it is gets too long.

Here a part I made tens of thousands in past . It has red dikem to show it for setup not for uses.

¾" hex bar machine to fit 6203 ball bearing 0.6663" ±0.000,15 and thread ⅝" nf total length 5".

Turn at 750 rpm feed is 0.025"
Total time under 2 minutes including threading each end.

Did tried a feed if 0.1 but could not hold ±0.000,15 so I had to slow it down to 0.025" feed.

Dave

FYI Did try top speed of 1,000 rpm but cutting oil would throw out on to the floor

 

[timo_gross]

Running down a long thin rod at high speed using a bush steady, the unsupported outboard end can whip if it is gets too long.

Yes, valid reminder! Not careful it whips and is gone into the chip tray. (if the unsupported part is big enough maybe it gets even dangerous) To avoid whiping the skinny end could be fed into a tube that is held by the drill chuck in the tailstock.

 

[SmithDoor]

Yes, valid reminder! Not careful it whips and is gone into the chip tray. (if the unsupported part is big enough maybe it gets even dangerous) To avoid whiping the skinny end could be fed into a tube that is held by the drill chuck in the tailstock.

It is support like follower rest.
It is one pass finished
There is no second pass


Dave