[dalianharley]

Hi all,

I got a small part which requires 5 different size of holes to be drilled. I'm considering adding more jacob chucks so i can preset the tool length. However i'm not sure which one should I pickup, tormach sells 4 different sizes of jacobs and my drills are most around 2~4mm sizes. I'm looking for keyless for easier bit change. Which ones would you guys recommend?

thanks!

Daz

[LSM]

None use an er16 or er20 collet holder just need the right size collet much less run out, drill chuck is kind of a waste of money

[RussMachine]

drill chuck is kind of a waste of money

I wouldn't go THAT far.
I agree that you should use collet holders first. BUT if you don't have enough holders, or don't have the correct sized collets, there's nothing wrong with using drill chucks.
Personally, I like the larger one that has 1/2" capacity.
A large chuck can hold small drills, but a small chuck can't hold large drills.

[dalianharley]

I did buy a couple of more ER holders. But a lot times when we r just prototyping we found it's a lot easier to use a chuck for frequent drill bit change. So I wanted to pick a keyless chuck for that purpose hence my questions here. Thank y'all for the advices. I'll get a bigger chuck then. We will be using ER holders if the part is to be made in a small production level.

Why would they make all these different JT sizes if 1/2 can do it all? and why the 5/8 chuck is even cheaper than the 3/8? Just curious...

30245 - Keyless Drill Chuck - 3/8" - JT2

[waltpermenter]

Why would they make all these different JT sizes if 1/2 can do it all? and why the 5/8 chuck is even cheaper than the 3/8? Just curious...

30245 - Keyless Drill Chuck - 3/8" - JT2

because 1/2 inch can't do it all as you say. there are many sizes of chucks each suited for their application and there are many JT sizes correspondingly. JT (jacobs taper) sizes range from JT0 to JT5, they almost go in order from smallest to largest by diameters (JT6 is out of whack though) Machine Tool Shanks (Tapers) you'll notice tormachs 1/4 inch keyless chuck uses JT1 and their 5/8 keyless uses JT6. They offer several sizes of JT because there are lots of sizes of chucks and manufacturers can use whatever size JT they desire. notice tormachs offerings, a 1/2 inch keyed chuck and the 5/8 keyless both are JT6. Pick your chuck first then the JT to match.

[waltpermenter]

also surely you can understand that not all chucks are made the same with the same quality and by the same country of origin, hence the price differences. go price some quality US made chucks like Jacobs.

[tbaker2500]

The jaws of the chuck have flats on them, to press against the drill bit. On larger chucks, the flat is larger. A larger flat means that that it can't grip a small bit, since they don't all come together in the very center. So there definitely is a minimum size drill bit you can use in a given chuck.

[pickled]

If you are working with smaller bits (and are certain that you want a chuck) a lower profile chuck may be more desirable. I say this for the simple reason that the large keyless chuck eats up a bit more of your total Z travel. Thankfully the 1100 gives you a good amount of Z range, but if you have a 770 every little bit is helpful.

[dalianharley]

Thank you all for the great info! I ended up buying 4 more ER20 holders and a JT6 keyless chuck. Now it's time to work on my tool offset table!

[popspipes]

I have chucks for drills that arent used often and vary in size, I use 1/4" chucks for the small drills and the 1/2" ones for larger drills.
The ones I use regularly I use er20 collets for.

I have several battery drills with the keyless chucks, and I am not a big fan of those as they tend to slip after they get quite a bit of use. They are nice in the respect that you dont have to hunt for the misplaced chuck key at times.....

[SCzEngrgGroup]

I have several battery drills with the keyless chucks, and I am not a big fan of those as they tend to slip after they get quite a bit of use. They are nice in the respect that you dont have to hunt for the misplaced chuck key at times.....

Actually, there's little benefit. You can hand-tighten a keyless chuck for a small drill, but for larger ones, you need to use a pin wrench to get it tight enough. So, it's key-less, but not tool-less. Personally, I am not a fan of keyless chucks, unless you spend the $$$ for really good quality ones. Otherwise, they'll work for a while when they're new, but eventually end up slipping on you.

Regards,
Ray L.