• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.
  • Guest,  We want to wish You and Your Family a Healthy, Happy Thanksgiving! Click the "X" at the top right corner to remove this notice)
  • PLEASE: Read the FORUM RULES BEFORE registering!

4

What size straight shank for drill chuck?

3
Like what you see?
Click here to donate to this forum and upgrade your account!
10

T. J.

H-M Supporter - Premium Member
H-M Supporter-Premium Member
Joined
Oct 31, 2015
Messages
175
Likes
175
#1
Is there a rule of thumb for sizing a straight shank arbor for a drill chuck? This would then be held in an R8 collet in the mill. For instance, I have a Jacobs 14N, which is a 1/2" chuck. I would assume that you would want the arbor to be at least 1/2". Am I off base on this? Are there other factors to consider?
 

Bill Gruby

Global Moderator
Staff member
H-M Supporter-Premium Member
Joined
Jul 13, 2012
Messages
5,430
Likes
1,900
#2
It would depend on the collet size you use and also your comfort zone. If it were me a 1/2 inch shank would suffice for a 1/2 inch chuck.

"Billy G"
 

Bob Korves

H-M Supporter - Premium Member
H-M Supporter-Premium Member
Joined
Jul 2, 2014
Messages
4,032
Likes
4,183
#3
Some of the choice can be convenience. If all your tooling has the same shank, then the same collet or Weldon holder can stay in the spindle, saving lots of time and effort. Of course, running a 3/4" capacity drill chuck with a 1/4" shank would be silly, also the reverse of that. Straight shanks also have no need to be longer than the gripping surface that holds them. Shorter shanks make for quicker tooling changes, and can often be easily changed in tight setups without moving anything. Changing collets takes more time. For some jobs the added strength of integrated shank tooling can be a good thing. For accuracy, either can work, and if the high sides of the individual components are marked on them, accuracy can actually be gained by the additional interface.
 

Grandpop

Active Member
Active Member
Joined
Jan 20, 2016
Messages
37
Likes
37
#4
I have a home-made 5/8 straight shank on the drill chuck I use most often (5/8 cap), about 2-1/2 - 3 inches long. Was an old broken off ball lock punch shank that I just ground the mating taper onto and pressed in. Easy to get in and out without changing height most of the time. I uses 5/8 since the boring head I bought came with that same size, so easy to switch between drill and boring.
 

darkzero

Global Moderator
Staff member
H-M Supporter-Premium Member
Joined
Nov 27, 2012
Messages
2,993
Likes
1,713
#5
1/2" is convenient if you use 1/2" edge finders. After dialing in a part you can switch to a drill chuck quickly.

One of my 14Ns came with a 1/2" shank. The shank wasn't in the greatest shape so I replaced it. 1/2" just seemed way to small for the size of the 14N so I put a 5/8" shank on it as that's what I have on my Tapmatic. Well now I barely use that 14N cause I rarely use a 5/8" collet. 1/2" collet is really the only one I ever use for R8. I find myself using my chucks with R8s (I have a 14N with an R8 also) most of the time. I think I may switch that other 14N back to a 1/2" shank even though it looks funny.
 

T. J.

H-M Supporter - Premium Member
H-M Supporter-Premium Member
Joined
Oct 31, 2015
Messages
175
Likes
175
#6
Thanks guys - all good advise. I have another chuck (an old #14) that I could use on the mill as well. Is there an advantage to having one with an R8 shank when space above the table isn't an issue?
 

darkzero

Global Moderator
Staff member
H-M Supporter-Premium Member
Joined
Nov 27, 2012
Messages
2,993
Likes
1,713
#7
Thanks guys - all good advise. I have another chuck (an old #14) that I could use on the mill as well. Is there an advantage to having one with an R8 shank when space above the table isn't an issue?
Not much really that I can think of, possibly a bit more rigidity with a R8 shank but for hobby machining it wouldn't matter & there shouldn't really be much any side load using a drill chuck. R8 shank just takes longer to swap in/out compared to a short straight shank. You also introduce a bit more possibilites of run out with a collet & a straight shank but it's a drill chuck so that doesn't matter.

Only thing I don't like about straight shanks is you have to be careful when tapping the drawbar to release the collet. With a drill chuck that has some heft to it like a 14N or bigger, you have to hold the chuck in one hand to make sure it doesn't drop down damaging your part, table, vise, etc but I do that with anything held in a R8 collet. With a R8 at least the draw bar threads is still engaged in arbor so you don't have to worry about it dropping out of the spindle.

I have a 14N with a straight shank & another with a R8, I prefer to use the R8 more, it just feels better to me. But I mainly use a keyless chuck with R8. I have a little Jacobs keyless chuck mounted on a short 1/2" straight shank which is very handy, no way would I want that one on a R8 shank. It's all personal preference I guess, straight is much quicker to use but I'm just a hobby guy, saving time does not always matter to me.
 

EmilioG

Active User
H-M Supporter-Premium Member
Joined
Jul 20, 2014
Messages
968
Likes
342
#8
I just switched one of my 14ns to 1/2" straight shank stub arbor. It came with a 14n I purchased and put it away.
It's a vintage USA stub straight shank, which I don't see very often. A lot of people cut arbors down.
What JT size do you use? I may have an extra. I have about 20 arbors.
 

T. J.

H-M Supporter - Premium Member
H-M Supporter-Premium Member
Joined
Oct 31, 2015
Messages
175
Likes
175
#9
I just switched one of my 14ns to 1/2" straight shank stub arbor. It came with a 14n I purchased and put it away.
It's a vintage USA stub straight shank, which I don't see very often. A lot of people cut arbors down.
What JT size do you use? I may have an extra. I have about 20 arbors.
I've already got one on the way. Thanks for the offer though!
 

4gsr

HM Chief Foreman
Staff member
H-M Supporter-Premium Member
Joined
Aug 8, 2011
Messages
4,406
Likes
2,666
#10
I have several straight shank drill chucks I keep on hand, mainly 3/8, 1/2, and 5/8". They are handy when you don't want to pull your collet holder just to drill a hole or two. Just remove your endmill and insert drill chuck and go!
 
[6]
5 [7]