# Four into three may be the ticket



## malmac (Dec 11, 2018)

I have a small job to do for a friend. I need to cut some 6mm threads into some square section brass. I wanted to do it in the lathe but just did not want to go to the effort of lugging the 4 jaw chuck up onto the lathe.

So I bought a small 4 jaw chuck (100mm) and made a mounting plate for it that slots into my 3 jaw chuck. So for a small quick and dirty job - here is my solution.

The mounting plate is made from an upcycled hub from a small chinese built camper trailer I used to tow behind our motor bike.

I am sure there are other options but I think this will be a useful bit of kit to have on the shelf for small jobs requiring a 4 jaw chuck.


Cheers   Mal


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## T Bredehoft (Dec 11, 2018)

Bravo. I think I'd been tempted to chuck the  four jaw in the three jaw and go with it.


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## FLguy (Dec 11, 2018)

Me too.


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## macardoso (Dec 11, 2018)

Chucked straight on my mini 4 jaw. Definitely left bite marks.  Cheap Chinese cast iron. But its great. I have a 4 jaw scroll chuck for just this purpose.


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## malmac (Dec 12, 2018)

macardoso said:


> Chucked straight on my mini 4 jaw. Definitely left bite marks.  Cheap Chinese cast iron. But its great. I have a 4 jaw scroll chuck for just this purpose.



I would have done that too, but my 3 jaw just did not play - I could not easily adjust the jaws on the four jaw once I had it securely locked into the 3 jaw. That problem, for me is now solved. Lucky for you that you did not have to go to the same amount of trouble I went to.


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## Mark Needham (Dec 12, 2018)

Just on 53 seconds. 1 minute. to change the chucks. Not sure what the problem is. I spend, ( read waste) more time on the crapper. lol


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## malmac (Dec 12, 2018)

My four jaw chuck weighs in at around 45kgs - I can't even lift it without the small crane device I have built to lift off the three jaw and replace it with the four jaw. The downside of having a medium sized lathe. But if I could do it in 53 or even 153 seconds I would not have gone this way.


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## Tozguy (Dec 12, 2018)

Mel, great job, having the trailer wheel hub on hand sounds like a stroke of luck.
Did you size the 4 jaw to fit the hub or did you want a particular size of chuck from the start?
What size 4 jaw is it?
Although I change out my 8'' 4 jaw without hesitation, I can see how handy it would be at times to have a quicker option.


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## malmac (Dec 12, 2018)

Tozguy said:


> Mel, great job, having the trailer wheel hub on hand sounds like a stroke of luck.
> Did you size the 4 jaw to fit the hub or did you want a particular size of chuck from the start?
> What size 4 jaw is it?
> Although I change out my 8'' 4 jaw without hesitation, I can see how handy it would be at times to have a quicker option.



I just wanted really the smallest 4 jaw which is a four inch job. I thought I would be able to just throw it in the three jaw which is about 10 inches across - but did not work well because I could not easily adjust the 4 jaws. I could have made a long reach tool to do the job, but opted for a backing plate.
I just found the old hub on my shelf and thought, aaah this might work.

Have a great day.


Mal


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## Janderso (Dec 22, 2018)

Very nice work!


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## malmac (Dec 22, 2018)

I was turning up a custom tap the other day and the only part I had to hold on to after it had been in the mill was the square shank at the end - in went the little four jaw and a fairly quick set up and I was able to get to work. Won't use it every day but it is there when I need it for those small jobs that don't require a big solid 4 jaw.


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