Lathe soft jaws, money saver

[thehomeengineer]

Soft jaws are not cheap so this is a hack can save a lot of money in replacing old machined out jaws. This set up also allows for the jaws to be kept if a repeat job comes up again and again. Also you can custom make the jaw lenghth to suit the work piece (within reason). I have also setup the chuck on the mill and bored a set with a known offset to produce several cams which I wanted to all be the same.
This may be useful if you use soft jaws alot. Link to website and photos.
Practical Engineering

[extropic]

I like the hexagonal sacrificial jaws shown here but I have questions about the linked information.

"The standard soft jaws machined to take the bolt on hexagon sacrificial jaw" is a caption from a photo at the link.

It looks, to me, like the "standard soft jaws" are one piece jaws that also engage the scroll. I can't see where a soft top jaw is attached to a hard master jaw, as I would expect. Are there fasteners hidden from view in that pic? What am I missing?

Are the "standard soft jaws" custom made to fit that Pratt chuck or are they commercially available?

Are those "standard soft jaws" made of steel?

I've never seen a "soft jaw" that REPLACE the standard (hard) jaw in a factory chuck.

I'm used to seeing hard master jaws on the chuck with removable soft or hard top jaws.

What size (diameter) is that chuck?

Please clarify what's going on with that chuck.

[thehomeengineer]

Hi Extropic
I am guessing you are based in the US?
In the UK manual lathe chucks come with two sets of hard jaws with the scroll machined into the back of them, so to change from internal to external jaws the complete set of jaws are removed and replaced with the second set (in the correct order to ensure the chuck runs true). So in the case of the soft jaws they are also one piece steel construction and just replace the standard jaws. These are then machined as required but this can get very expensive. So I adopted the US style of master jaw so I could bolt my own jaws to the chuck. The nice thing is you can make the sacrificial jaws out of any materail to suit your aplication ie aluminium, steel, plastic etc.
I beleive the US prefere internal, external jaws which bolt to a master plate with the scroll machined into the back and the jaws bolted to the front?
I hope this has answered your questions if not please send another email
The Home Engineer

[thehomeengineer]

Photo of a set of new soft jaws

[DIYer]

Thanks thehomeengineer! We've added your Soft Jaws to our Lathe Accessories category,
as well as to your builder page: thehomeengineer's Homemade Tools. Your receipt:

Soft Jaws by thehomeengineer

tags: soft jaws

[extropic]

Yes, I'm in the USA and, thanks to your reply, I understand now.

I wasn't aware of "soft" replacement jaws being a factory option.

Nice job, all around.