My lathe is older than dirt

[Bill Shields]

Ah yes .

But I truly love my Buck adjust true 6 jaw..

[pete]

No question about the soft jaws. And Harry knows this better than I do, model engineering is sometimes hugely different than most job shop type work. Even more so for any that just don't have a mill for whatever reason. I agree about the only one chuck make it a four jaw part. But I'd also want that four jaw AND a face plate. A large number of my reference books and magazines are fairly old pre 1970's. I've seen it stated quite a few times in them that most simply couldn't afford any British built mill and today's off shore machines just weren't available as a cheaper alternative. At most they had a lathe and drill press and maybe a shaper if they were lucky. So locos, stationary gas and steam engines, tool castings were all designed from the start to fit and be machined on lathes with on average a 9" swing range and that lathe filled in for having no mill. Even today, the majority of the available casting in the UK are from that time period and lots still come with additions on the castings so a four jaw can hold them and that can be removed later.

There's also hundreds of pictures in those same books and magazines showing face plate set ups because a four jaw couldn't open or sometimes be offset enough. Yeah it's really slow to set up and indicate the part in, and today almost worthless in a real money making shop unless you were desperate. But when you have no other method available you use what you do have. One of my books written in 1907 shows master gauges being bored and ground on sleeve bearing lathe face plates to accuracy levels that would be extremely difficult to maybe impossible to duplicate with a brand new Bridgeport, a very expensive air turbine to drive and offset the stones and a really good dro. They were jig boring and grinding on a lathe face plate before those machines were even invented.

[Harold_V]

Ah yes .

But I truly love my Buck adjust true 6 jaw..

They are nice, of that there is no doubt, but they pale in comparison to soft jaws with pie jaws when gripping thin-walled objects.

There's been no mention of a two jaw chuck, but it would be a nice addition to anyone's shop. (I don't have one!) I surely wouldn't want it to be my only chuck, however.

H

[Bill Shields]

Have 4 jaw and 3 jaw with soft jaws also...but the 6 jaw gets a lot of use..

[Harold_V]

Have 4 jaw and 3 jaw with soft jaws also...but the 6 jaw gets a lot of use..

Understood! It's much faster than preparing soft jaws, especially if it's just a "one off", where the time spent preparing soft jaws isn't recovered, as is often the case.
I recall spending more than a year on a Clausing, machining only small parts (job shop). The lathe was equipped with collets, plus it had a six jaw. Nice chuck!

H

[RET]

Hi,

One thing I haven't seen mentioned in this thread is that when machining a chuck back plate to match a lathe spindle, for accuracy it is important to fit the back plate to the lathe spindle face and diameter behind the threads. When done properly, the back plate threads are a bit sloppy on the spindle and they just hold the plate on the spindle, they don't locate it.

A couple of years ago now I bought a Bison 5C collet chuck and a precision 3 jaw chuck and made adapter or backing plates for both of them from some cast iron I had. It took a while to do and the cast iron made quite a mess of the lathe, but it was really worth doing. The 5C collet chuck I find especially useful. The precision 3 jaw has reversible jaws, so that can be really handy as well.

The important thing is to fit the adapter plate to the spindle as precisely as possible; a thou or less is good if you can manage it. Remember however, that once the plate is properly fitted to the spindle, you are just nicely started. You still have to fit the adapter plate to the chuck! It is also a good idea to put a hole for a hook wrench in the adapter plate shoulder for easy removal.

In all this, being slow and careful and planning ahead pays considerable dividends.

Been there, done that.

Richard Trounce.

[milwiron]

Yeah it's really slow to set up and indicate the part in, and today almost worthless in a real money making shop unless you were desperate.

I guess it's all relative.
For our hobby sized stuff I absolutely agree.
Having worked in and managed very profitable production "money making shops" with vertical lathes with up to 10 foot swings and horizontals with 6 x 50 foot capacity I can honestly say we didn't have a soft jaw or collet to be found anywhere. For an experienced machinist setup is surprisingly fast.
Our toolrooms had smaller machines that did some outside work, fixtures and machine repair parts. The toolrooms were profitable and seldom had use for soft jaws, we did have 'em though.

Still in the U.S. there are many money making shops around that do much, much bigger machining than I ever did.
Denny

[Harold_V]

Work size is everything. It stands to reason that shops that handle large work wouldn't benefit much from soft jaws or collets. Even at 2" diameter, collets become an unreasonable option due to extreme cost and limited application. Easily justified for a production setup, however.

When I ran my machines for gain, I specialized in small work. I'd have not thrived without soft jaws and collets.

H

[paralleler]

My lathe is similar to yours and I picked up a used four jaw chuck from Lost Creek Machine Tools. You might look through their current selection:
https://lostcreekmachine.com/product-ca ... he-chucks/