Drill Press Chuck Taper Size

[Keith Strong]

I have a 20 year old el cheapo imported drill press, Sold under a few "value" lines, cummins, harbor frieght... I need to get a new chuck since the existing one will not hold really small drill bits.

Measuring the arbor, it seems like the closest size is to a JT3 or 3JT but not exact. Before I order one, does this size sound correct for one of these foreign made drill presses.

Thanks for your help.

[david brum]

Is that a full size or bench top drill press?

[Keith Strong]

Its a bench top model. Looks very similar to this model:
http://www.woodcraft.com/Product/2080314/28952/General-14-Bench-Top-Drill-Press.aspx

Thanks.

[david brum]

Keith, here's a chart borrowed from wikipedia.


Jacobs[edit (http://en.wikipedia.org/w/index.php?title=Machine_taper&action=edit&section=5)]The Jacobs Taper (abbreviated JT) is commonly used to secure drill press chucks to an arbor.


Taper
Small End
Big End
Length



mm
inch
mm
inch
mm
inch


0
5.80
0.2284
6.35
0.2500
11.11
0.4375


1
8.47
0.3334
9.75
0.3840
16.67
0.6563


2
12.39
0.4876
14.20
0.5590
22.23
0.8750


2 Short
12.39
0.4876
13.94
0.5488
19.05
0.7500


2½
15.88
0.625
17.20
0.677
26.80
1.055


3
18.95
0.7461
20.60
0.8110
30.96
1.2188


4
26.34
1.0372
28.55
1.1240
42.07
1.6563


5
33.43
1.3161
35.89
1.4130
47.63
1.8750


6
15.85
0.6241
17.17
0.6760
25.40
1.0000


33
14.23
0.5604
15.85
0.6240
25.40
1.0000

[Joe Kaufman]

33 is a common size for DP. Some have a threaded locking collar.

Joe

[Kyle Iwamoto]

Be careful, there are metric sizes too, if your drill press is a cheapo import like mine...... (I think, mine matches none of those in the table) After a long search, I located a chuck for 149 bucks. ALMOST as much as I spent on the DP itself. Nah pass. Buy a new one.