4 Jaw Chuck Adaptor Plate For Lathe

[Jigantor]

That square hollow section begged to be trued by the new lathe chuck. So I turned the revs down to 160rpm and feed rate was 0.05mm per pass. The tube was cut by a aluminium drop saw so only need 4 passes per end.
Using a dial indicator was pretty confusing as I could not get it any closer than .05mm. Then I saw what was happening. The tube walls were deflecting inwards from the force of the chuck jaws.
Oh well it was centred.

worked better than expected.
Ji

[justracn15]

Mounting plates are normally made from cast iron or steel because they are more stable than aluminum. Wondering why you didn't just chuck the 4 jaw in the 3 jaw? Have a 4 jaw that doesn't fit any of my lathes and use occasionally and that's how I grip it.

[Jigantor]

Hi Just,
Thermal expansion alters aluminium's dimensions that is for sure. I don't turn all day long or take large bits so my chuck and base plate don't really get hot, but just in case that does happen that is why I made the base plate so it needs some heat to even fit. After that it is just a spacer so aluminium should do fine as my machine does not spin real fast (max is 1600rpm).
I have never had a 4 jaw chuck so did not think about holding it with the 3 jaw, great suggestion. My 3 jaw and 4 jaw weigh a bit, combined that is a fare old weight being supported by the bearings without the job weight spinning force or tool pressure. Have you ever had yours fly off or just fall onto the bed? What size 3 jaw chuck do you have in comparison to your 4 jaw?

Ji

[Jigantor]

Truing the square hollow section yesterday took for ever. Mainly because I was fighting with the magnetic base holder. It was like trying to get someone to stand up that took a handful of sleeping tablets. Not wanting to go through that again I came up with a design for a jig to hold the dial indicator in the tool post.
I found some scrap aluminium 20mm x 20mm 6061 square bar hanging around so off to the mill I went.

Ji

[Jigantor]

I don't have a slitting saw so I cut the compression gap with my band saw. Not to bad.
It holds the indicator perfectly.
No more fights or lost time.

Ji

[WyoRoy]

Nicely made holder. I have to ask...why not just use your mill to true up the square tube?

[Jigantor]

Hi Roy,
Exactly.
The mill would have been better alround but it was the only square stock I had hanging around to test the new chuck.
It needed squaring for another project and I found out I needed this indicator jig to use the chuck so it all worked out.

Ji

[WyoRoy]

Makes sense in oh so many ways! Looks like it's about time to invest in a finger style indicator for your lathe work. I've a number of old lug back plunger indicators, but a finger style is so much easier to use on a tool post.


EDIT: Actually, I find a Noga brand mag base indicator holder invaluable.

[Jigantor]

Hi Roy,
I have one of those lever type indicators but for squaring square it only moves a little bit before end of travel while the dial type has heaps to avoid the corners. May be there is a better way but I have not been shown it.
Thanks Ji

[WyoRoy]

If it works for you, that is the only thing that matters. I've been known to plop down a section of 1" flat stock across the lathe ways and sit a surface gauge on top to rough align stock in the chuck before bringing out the indicators.

[Jigantor]

Hi Roy,
Have you got a stock stop for your mill.
When rounding the corners I marked a line on my vice so I could spin the part but have it align again without adjusting the X,Y,Z.

Ji

[WyoRoy]

Hi Roy,
Have you got a stock stop for your mill.
When rounding the corners I marked a line on my vice so I could spin the part but have it align again without adjusting the X,Y,Z.

Ji

Stock stop...no. I use either a clamp on jaw stop on the Kurt vise or wind down a long T-bolt on the table next to the vise and work with that for a reference.


You should be able to modify your new indicator holder to work on the mill table to catch the front edge of the work you need to mill to get the work piece indexed. See below...

[Jigantor]

Hi Roy,
Wow is that your mill? Pretty cool stuff. I thought about bolting something into the tee slots. I was thinking about making a permanent stop fixed to the vice. Something to index a part from both sides of the vice.
Ji

[WyoRoy]

No, not my mill...just a quick and dirty Google photo search result. Here's my old gal.

[Jigantor]

Still a good looking mill.
Well built machinery seems to work forever.
Ji