Jacobs Flex collet chuck vs 5C Collet Chuck

[Happycamper]

I just read wrmiller’s post on his new TMX 5C chuck that a friend gave him(lucky dog!). I’ve been thinking about getting one (Tool-I-Tus?) But, I already have a Jacobs flex collet chuck. I would think the 5C would be a little more rigid and accurate than the flex collets. The Jacobs flex set that I have show little wear but it seems to me that relying on a rubber material to hold the collet splines might lead to some flex. Most of the time I’m chucking up smaller pieces and have to make and use a short spacer of the same diameter as the piece I’m chucking up in order to completely fill the collet’s length. Is that the case with 5C collets? Or, can you insert part way into the collet and it will hold? I guess the thing I like about the Jacobs collets is that each collet has a range of .100 so I have 11or 12 collets and that takes me from .100 up. Let’s see, 12collets or 35 to 57 collets? And I understand that there’s not much range with the 5C collets, is that right? That’s a plus for the Jacobs. So, enough babbling, anyone out there have experience with both the Jacobs and a 5C chuck that can enlighten an old fart?

 

[mmcmdl]

Jacobs flex collets have plugs for short length parts . The chucks and collets work for most types of parts . Any super precision parts , I would go with the 5C collets . They also make machinable collets so you don't have to spring your standard sizes .

 

[mksj]

One major problem with collapsing collets is as you mentioned that they need to hold stock their full length, so like the Jacobs or for that matter ER collets to prevent collapse at the other end of the collet they need something like at least 1/2 the collet holding the stock. There are plugs, but kind of defeats the collapsible range as the plug in theory should be the same size as the stock. Also you might get more axial skew. I can't find any spec's on the Jacobs collets, but probably much worse TIR and rigidity of holding the part.

The 5C collets holds stock at the tip, the width of the holding area increases with the diameter collet size (but is still short compared to ER or Jacobs collets). The 5C drawback has a very limited clamping range, in my experience you need a 1/64th collet set to cover the gaps in the ranges, and even with that there are some diameters that fall through the cracks. The positive side of 5C collets, and a 5C set-tru type chuck is accuracy, minimal TIR, and ability to hold very short stock. I am routinely holding stock that is as short as 0.25" long securely, I couldn't do that with most other collet systems. The other real plus is the ability to hold threaded stock without damaging the threads. Did that a few times in my 3 jaw, and just didn't work well, that is when I got my Bison 5C chuck. CDDCO sells a 1/64th 5C collet set for around $225, well worth it and decent quality. Do not buy the cheap Chinese direct mount 5C chucks, the are pretty bad as to accuracy and function. The TMX/Bison 5C chucks are mighty nice.

 

[Happycamper]

Jacobs flex collets have plugs for short length parts . The chucks and collets work for most types of parts . Any super precision parts , I would go with the 5C collets . They also make machinable collets so you don't have to spring your standard sizes .

Do you need the plugs for the 5C collet? And what is the range on a 5C? We posted bout the same time misjudged and I see you answered my questions.

 

[Silverbullet]

I used a Jacob's flex collet for work holding on a lathe one time in vokie in the early 70s. At that time the work pushed sideways in the jaws . So I've never used one on a lathe since. It ruined a project that was to be graded ,start all over , redoing them cost in the academic part and it don't setup good business practise either. Just my view on those , never ever had a 5C let a part push sideways . I have a tapping head that used them , I switched it out for metal collets to hold the taps . I don't trust them at all.