Thread: Setting up in a 4 jaw independant

Originally Posted by pipeclay

Can you explain the method that you used in setting up the length of brass bar in your lathe with the steady.

Was the od of the brass concentric.

For a beginner, probably easier for me to explain what I'm trying to accomplish.

I've made some small brass cannons and they have turned out (if I do say so myself) rather brilliantly, so I wanted to up the ante and make a bigger cannon for my grandson for Christmas. I bought a piece of brass 65mm x 300mm for $70.00 and wanted to set it up in the four jaw chuck and use the steady to bore it out as the first step in the process.

g'day a job like that a little deflection wont really mater.
so the job wont fit down the spindle bore?
of course not.
whats the next step.
as far as the packers on the chuck jaws.
even if you use the tail-stock to center
the job while setting up the steady if you
check the the set up perfect at the chuck
you will get some run out at the steady.
the packers in a way act like a cv joint.

Originally Posted by Gavin Newman

I can generally get it done in a couple of minutes.

smart ass....I will ring you to come over and help when I next have fun....

Originally Posted by welder

Simon I am not 100 % but you should always use the packing regardless of the chuck as the bar will sag slightly. On another note you can use the tailstock center to hold the work in roughly center while you tighten the chuck.

Hi Andre. OK thanks. WRT centring with the TS, I had done this previous, using the dead centre to locate on a centre punch. I mainly use this method if the exact location is not important, or a rough location on the centre punch is good enough. My centre punching skills are rather lacking and they always tench to be bias to one side, if looked under magnification, which effects accuracy.

Simon

Originally Posted by simonl

Hi Andre. OK thanks. WRT centring with the TS, I had done this previous, using the dead centre to locate on a centre punch. I mainly use this method if the exact location is not important, or a rough location on the centre punch is good enough. My centre punching skills are rather lacking and they always tench to be bias to one side, if looked under magnification, which effects accuracy.

Simon

I haven't looked into it, but have wondered if you could make up a centre punch guide for a round stock end, based on a 45 degree hollow cone to fit over any moderate diameter end ?

Just a thought. Make it out of aluminium.

Anything commercially available?

Rob

Originally Posted by nearnexus

I haven't looked into it, but have wondered if you could make up a centre punch guide for a round stock end, based on a 45 degree hollow cone to fit over any moderate diameter end ?

Anything commercially available?

RDGTOOLS ENGINEERS BELL PUNCH / CENTRE FIND EVERY TIME | eBay

Nothing new under the sun?

Michael

Originally Posted by Jim Ferrous

Is it a casting,or a piece of stock,has it already been machined?

Round brass (machined 65mm round)

Is it an OD or ID your setting up?

OD

Is it a short piece of stock or is it long?

300mm supported

Are you using a surface gauge,pointer or indicator to set up?

Tried pointer and an indicator


I get it right and when I tighten down, it goes out of whack.

Hi Jim,
I have only used the one key method but am seriously looking at the two key method.
To set up your particular job I would use the surface gauge, sitting on the carriage, up near the chuck first.
Then move the carriage to the other end and use a rubber mallet to adjust. Remember to not move the position of the surface gauge on the carriage.
Return to the chuck end and repeat the whole procedure if necessary.
Depending on the level of accuracy I would then change to a dial indicator mounted in the toolpost and do the same procedure.
Like everyone else (pretty much) I loosen a jaw then tighten the opposing jaw until the piece is within the accuracy required.
The last bit is done by tightening the offending jaw only without loosening the opposite which can move the piece the last 0.0005".
Now, as you are using a fixed steady, there is always the possibility that when tightening the three supports, the end can move slightly and this then tries to screw the piece out of the chuck (hence the aluminium packer pivots/job protectors).
To check this I use a centre finding gauge which normally comes with a combination square set and mark out the centre of the shaft.I then use an automatic centre punch or nowadays the optical centre punch and put a tiny mark in the end.
I then set up the 'wobbler and check that I don't move the job when tightening the fingers on the steady. If I do move the piece, this is indicated by a large movement at the other end of the wobbler.
I have thrown in a pic of the Wobbler I made.

Phil
Copy of Workshop tools 025.jpg

Originally Posted by Michael G

RDGTOOLS ENGINEERS BELL PUNCH / CENTRE FIND EVERY TIME | eBay

Nothing new under the sun?

Michael

Ha Ha good one Michael. Well done.

I wonder how well they work ?

I might have a go at making one of those.

Cheers

Rob

Nothing to do with cannons or alignment but it might prove handy to someone.

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I have used a 3/8 socket adapter (1/4 in hex - 3/8 square) in my cordless drill for quick movement in my 4 jaw.

Dean

Originally Posted by Anorak Bob

Nothing to do with cannons or alignment but it might prove handy to someone.

003 (Large).JPG

speed brace they used to come in socket sets. and i used to use them a lot for engine work.
i just keep looking at the lathe head stock. its on my to do list upgrade from a 9c to
a 9ar.
just have to find the right one at the right price
arron

Originally Posted by eskimo

smart ass....I will ring you to come over and help when I next have fun....

The trick is that I leave the 4-jaw on the lathe for most of the time and that forces me to practice.

Originally Posted by Gavin Newman

The trick is that I leave the 4-jaw on the lathe for most of the time and that forces me to practice.

Another thing I do that helps is that I have added thick steel sleeves to my chuck key grips (I use the same key for all chucks).

This makes it much easier on the hands, and in the case of the four jaw, enables me to use the grip ends as a small hammer to tap work into position.

Mainly used when setting up for facing cuts. Very handy.

Rob