Bill M's Pm1340gt Setup

Is that forged? The gator 8" forged set-tru I saw on fleabay was over $1100.
 
My 5C collet chuck has a TIR of about 0.0002" at the nose, but different collets can be out quite a bit at 4-6".

5c collets are not the best choice for work that far out of the chuck. Because 5C collets pinch the stock at the front edge there is always a chance of error due to the stock inside the collet not having the same hold. Assuming the stock is within a few thousands of the collet diameter, 2 to 3 times the diameter is about all I will do before using a center to support the work. If the stock is more than a few thou under size then a center should be used for extended work.

For precision 5C collets, Hardinge collets are as good as they get but they come at a cost.

The other thing that affects run-out with 5C collets is the fit of the tail end of the collet in the collet chuck. I have found that low cost imports (chucks & collets) can have a lot of variation.
 
Other ruminations: I know some folks almost exclusively use a four-jaw, but I have no desire to dial in every piece I chuck up. To me that's time I can better spend doing other things. Besides, this PBA once dialed in to a diameter will repeat much more accurately than any other 3-jaw I've ever owned. Even if the next piece is of a different diameter but within .5-1" or so of the piece dialed in.

But having said that, this chuck is probably a whole lot more, cost-wise, than most hobby/home machinists want to spend on a chuck to just play around in the garage. :)
Yes I agree. A scroll is much more convenient and quick for set up. I have no argument there. I don't look down on anyone, or blame them for using one.
For me its always about increasing my skills. (even if it takes me longer) Because for me I become more productive in the long run, even if it doesn't work like that right away. I will almost always do the toughest setup possible to push myself beyond my comfort zone. At work I just knock it out as fast as possible, because time is money. At home I don't care how long it takes. I look at home machining as education more than being fast or doing things the easiest way. I consider the independent 4 jaw tougher to dial in, and taking a higher skill set, so that's what I focus on. The more I do it, the faster and better I get. And that's ultimately what I'm working towards. Anyways, that's the simple explanation of why I mostly use the 4 jaw independent chuck. Did I mention I'm weird and eccentric? ;)
 
The other thing that affects run-out with 5C collets is the fit of the tail end of the collet in the collet chuck. I have found that low cost imports (chucks & collets) can have a lot of variation.
Agree on all points, that is why I currently have a Bison Set-Tru 5C, the generic Chinese 5C brands (which I have had a few) where pretty bad. I use Lyndex 5C collets in 1/64th increments. Even with all this, collet to collet TIR can vary quite a bit based on what you mentioned. I also have an ER-40 system that was given to me, but haven't used that in the lathe. I would expect it to hold better tolerance, but a bit more inconvenient to use. I just mention the different work holding systems and chucks, that chasing a 10,000th here or there is probably not worth the effort when you factor in all the other variables at this level of machinery.

On the 6J, there was also a previous post on the Shar's Set-Tru version and he was pretty happy with it, but I have purchased several Gator backing plates and the recent quality level has been very good. Seems to be a bit variable, but according to Ajax Industries who sells a number of brands, they feel the Gator is comparable to Bison in quality. The parts are literally interchangeable. Gator chucks also have a 2 year warranty. Still the Gator 6J in an 8" steel body Tru-Adj style is $1200, the Semi-Steel Tru-Adj version is $800 with a backing plate. I wouldn't spend this kind of money and not get a Tru-Adj version.
 
Instead of using a separate collet chuck I use an ER straight shank collet holder in my 6 jaw. Works great for the smaller diameter parts and with the set-tru 6 jaw I can dial in to very good TIR. Best is I don't have to switch out the chuck from the lathe.
http://www.amazon.com/C32-ER32-100L...g-Extension&qid=1460745002&ref_=sr_1_1&sr=8-1
51pzANRMAYL._SL1100_.jpg


51pzANRMAYL._SL1100_.jpg


51pzANRMAYL._SL1100_.jpg


51pzANRMAYL._SL1100_.jpg


51pzANRMAYL._SL1100_.jpg


51pzANRMAYL._SL1100_.jpg
 
Instead of using a separate collet chuck I use an ER straight shank collet holder in my 6 jaw. Works great for the smaller diameter parts and with the set-tru 6 jaw I can dial in to very good TIR. Best is I don't have to switch out the chuck from the lathe.

I don't have that particular one, but I too have a ER32 straight shank collet chuck that I grab with the PBA for really small stuff and/or working real close to the chuck (I REALLY don't like getting too close to this 8" PBA when I'm spinning it anywhere near 2k rpm. One little slip... :eek: )
 
I don't have that particular one, but I too have a ER32 straight shank collet chuck that I grab with the PBA for really small stuff and/or working real close to the chuck (I REALLY don't like getting too close to this 8" PBA when I'm spinning it anywhere near 2k rpm. One little slip... :eek: )
Yeah that could make for a really bad day! I'm looking at getting a ER32 straight collet chuck like that. Its on the never ending list.... ha
 
Back
Top