Finally got the first set of soft jaws done.
Milled the two slots in the rear, made the keys and tapered the front.
Nothing like the satisfaction of having drilled all these holes and milled all these slots and have the parts drop in place and all the screws go in.
OK, I actually, I had to hand file one key.
Note that I had to mount a vice in a vise to mill one slot, as my vise won't fit sideways and it won't open far enough (anyone have a 3" or 4" milling machine vise for sale/trade?).
These jaws are intended to grip work that runs through the spindle. The next set of jaws will be 1.5" or 2" tall so that you can mill the face many times to grip large diameter items, like wheels.
Steve
Chuck has a new set of shoes
Chuck has a new set of shoes
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Well done!
But I have one question. Maybe it's my own deficiency, but why did you use keys? I just milled my jaws to fit with a "tongue" in place of the key. I suppose the key is somewhat better in that it goes all the way across the master where mine is split by the groove. And it saves work and milling since you didn't have to drop the whole surface to form the tongue/key.
Open question for anyone, does it matter? Is one way significantly better than the other?
But I have one question. Maybe it's my own deficiency, but why did you use keys? I just milled my jaws to fit with a "tongue" in place of the key. I suppose the key is somewhat better in that it goes all the way across the master where mine is split by the groove. And it saves work and milling since you didn't have to drop the whole surface to form the tongue/key.
Open question for anyone, does it matter? Is one way significantly better than the other?
Russ
Master Floor Sweeper
Master Floor Sweeper
The key is very important in insuring that the jaws don't move about under load, and repeat when being re-installed. If you're alluding to machining the jaws with an integral key, that gets difficult because of the design. My three jaw uses keys as well, and there's no way in hell I'd use it without them. That would load the screws instead of the key, which, in my case, is hardened and ground.
Did I miss a point? Maybe I don't quite understand how your jaws mount.
Harold
Did I miss a point? Maybe I don't quite understand how your jaws mount.
Harold
Yeah, I'm afraid you did. 
Or at least sorta. I would NEVER use them without the cross "key". I just made the key as part of the jaw. The set of well cut up jaws that was on it had the key made in, and I just duplicated the way they were made. It was no big deal really, they fit snuggly in the masters on my 6" 3 jaw Pratt Burnerd. They take all three take firm thumb pressure to seat fully before adding screws, and you have to rock/wiggle/bump them (with my hand) to get them out. I've not noticed any repeatability problems, unlike my Buck with hard jaws that has at least a 0.001-2 crap shoot with hard jaws, frequently worse.
So is this a bad way to go? Seems to me that it's easier to get a good tight fit since you only have 2 surfaces to worry about, the front and back of the tongue going into the master. With keys, you have key to master fit, AND key to jaw fit. To me, seems like just one more place for things to go wrong. Am I missing something?
Or at least sorta. I would NEVER use them without the cross "key". I just made the key as part of the jaw. The set of well cut up jaws that was on it had the key made in, and I just duplicated the way they were made. It was no big deal really, they fit snuggly in the masters on my 6" 3 jaw Pratt Burnerd. They take all three take firm thumb pressure to seat fully before adding screws, and you have to rock/wiggle/bump them (with my hand) to get them out. I've not noticed any repeatability problems, unlike my Buck with hard jaws that has at least a 0.001-2 crap shoot with hard jaws, frequently worse. So is this a bad way to go? Seems to me that it's easier to get a good tight fit since you only have 2 surfaces to worry about, the front and back of the tongue going into the master. With keys, you have key to master fit, AND key to jaw fit. To me, seems like just one more place for things to go wrong. Am I missing something?
Russ
Master Floor Sweeper
Master Floor Sweeper
Chuckle!
Likely you're not missing anything. If I understand you, you just altered the longitudinal slot to allow for machining the cross piece in lieu of using a key. Had you not done so, the area of contact would have been somewhat compromised, which was my concern. I can see no reason why they wouldn't work to satisfaction.
Harold
Likely you're not missing anything. If I understand you, you just altered the longitudinal slot to allow for machining the cross piece in lieu of using a key. Had you not done so, the area of contact would have been somewhat compromised, which was my concern. I can see no reason why they wouldn't work to satisfaction.
Harold
When I first bought the chuck, my reaction was "how am I going to mill the part that fits in the slot".
I got a schematic of the jaws from Hardinge and saw that it had the key in the slot, so it was a lot easier than it first looked.
My keys were just made of the first thing I could find in 1/2", which was a peice of hot rolled steel. It was a bit oversize and not real smooth on the outside, so I ran it on the belt sander to clean it up. If I can get some ground stock in 1/2", I might make new ones, but these fit pretty well.
Steve
I got a schematic of the jaws from Hardinge and saw that it had the key in the slot, so it was a lot easier than it first looked.
My keys were just made of the first thing I could find in 1/2", which was a peice of hot rolled steel. It was a bit oversize and not real smooth on the outside, so I ran it on the belt sander to clean it up. If I can get some ground stock in 1/2", I might make new ones, but these fit pretty well.
Steve