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Replace the chuck on a low end bench drill press?


#1

For Christmas, I was given a low end 8" 5-speed drill press by
Tradesman. This is the NOT Craftsman drill press sold by Sears. I
love the 1/4 horsepower motor. The chuck that comes with it is
probably fine, as I am most likely not going to use it with drills
smaller than say, 55 or 57. However, I can tell that this chuck is
not a fine piece of machinery, and I’d prefer, at some point in the
future, to replace the standard issue chuck with a better quality
one.

How do I know what chuck to get? I called the Tradesman’s customer
service line and told the rep that I might one day want to replace
the chuck with one that could take smaller drills. I asked her if
there was a size to the spindle that I needed to be aware of when
looking for a new chuck, and (after asking someone else) told me “33,
tapered.”

Can someone explain this to me? I went to both the McMaster-Carr and
the MSC websites and it wasn’t long before I started to feel
bewildered. (What does “33, tapered” refer to?) MSC seems to have
more of a selection.

Thanks,
Christine in Littleton, Massachusetts


#2

Christine, Are you sure they did not say “J3” taperor “JT3” or “3JT”?
That would denote a #3 “Jacobs taper” That is a standard designation
for a chuck taper, you will find that in any of the catalogs you
mentioned.

Not sure if that is so, but it would be my guess. I’m not familiar
with that particular drill press, but you could always remove the
chuck and measure the taper. Dimensions would be found in a copy of
the machinist’s handbook, or in any number of other sources either at
your library or on-line.

Hope that helps, Al in Dracut, MA


#3

Hi Christine,

I asked her if there was a size to the spindle that I needed to be
aware of when looking for a new chuck, and (after asking someone
else) told me "33, tapered."

Drill chucks are usually attached to the quill of a drill press in
one of two ways. The 1st way involves a threaded connection similar
to a nut & bolt; the quill is threaded like a bolt & the chuck is
threaded like a nut. The 2nd way involves the used of a tapered
connection. The hole for connecting the chuck to the quill is
tapered & ground smooth. The end of the quill also has a matching
taper. The chuck is pressed on the tapered quill. The nice thing
about this type of connection is that it holds very tight, yet can
be removed with out causing damage (usually).

This 2nd method usually uses a shank that is tapered with a taper to
match the chuck (usually a #33 Jacobs taper) on one end & a #1, #2
or #3 Morse taper on the machine end. (the different Morse tapers
are used to accomodate small & large machines. This scheme makes it
relatively easy to exchange tooling on the machine.

The #33JT is a standard taper used for a lot of 0 to 1/2" drill
press chucks. When looking in a catalog for drill chucks, look for a
column label Mounting Type or JT Taper Mount. There are several
different tapers used for mounting chucks.

Dave


#4

Christine;

Hello. This is going w-a-a-a-y back in years. About 25 or more
when I worked in an industial tool supply store. Which would be a
good place to find the item - look in phone book or Thomas Register.

Can’t remember the exact details of what it means, but I believe 33
taper is refering to a specific Morse taper (spelling may be wrong).

It refers to the shape, taper, and length of the highly finished
piece of the chuck that will fit into a matching reciever on the
drill. It stays in but still can come out with a good downward wack.
I think it’s held in by magic.

Eric


#5

Hello Christine

As an old Machine Repairman, Machinist, as well as a life long tool
freak (ok jeweler, and lapidary and , for a living once, main frame
computer repairman, how is that for a ten word resume), the chuck
replacement may not give you what you want for fine drills.

First, find out if the quill, the mechanics which carry the chuck,
warrant any further improvements. This is not a question of the
brand of drill press, but rather the drill press you have. The
tolerances of the off shore produced drill presses are not very
tight. That means the you may have a very good piece of machinery,
or a dud.

The first test is, with the machine turned off, grab the chuck and
push, pull, move it side to side. Do you feel a lot of movement, or
just a slight amount of shift, or none. It things seem quite tight
here, you have a candidate for improvement. If you end up with a
lot of movement, then there is not much you can do to improve your
machine. I have a bench drill press that has enough wobble in the
quill to cause it to drill oversize holes. This isn’t to bad if
you are drilling 1/2" or larger holes, but for the jewelers, it
would never work, regardless of the chuck you would install.

There are a number of different mountings for chucks. Some mount
with a Morse taper “MT”, others with a Jocobs Taper “JT”, These
will have a number before the JT or MT to designate the size of the
taper. IE, a 1JT is a small version of the JT than say a 3JT. The
taper is the same angle, but the number designates the big end, and
small end sizes. A 3MT shaft will not fit into a 4MT socket.

Some of the drill chucks mount on a threaded shaft, usually a 3/8-24
thread, or a 1/2-20 thread, but some of the smaller ones will use a
5/16-16 thread. These threaded chucks sometimes have a lock screw
which is a left handed screw that you can access through the opening
of the chuck. This prevents the chuck from unwinding when turned in
a reverse direction. These are usually used on reversible hand
drills.

There are some other low cost chucks that use a different mounting
arrangement, but these are not desirable.

There are also some other taper shaft types the you might encounter.

The point here is that you need to find out what chuck mounting you
have before you can determine what you could replace it with. Once
you have found the mounting type for your machine, you then can
chose between keyed or keyless chucks, and between the capacity of
the chucks. The keyless are easier to use, but come with a big
price tag. The important thing is to get a chuck with a “0” min
cap… You will seldom if ever need a high capacity of over 1/4",
unless you are doing other work on the side.

I have two drill presses, a 1/2 tall bench unit which wobbles
something awful, that I use for large end work. I have a 3/8" small
bench unit which is really nice that I use for the more precession
work. In addition, I have a couple of small drill presses, for
Lapidary use, in addition to my Fordom drill. All get used at
times. None of them have the same chuck mounting.

You might also look at www.use-enco.com for chucks and such. They
have some lower priced machine tools and supplies.

Don


#6

Hi Christine in Littleton, Massachusetts,

The “33” chuck mounting on your drill press is a Jacobs #33 taper.
This is very common and MSC will have the best selection. The
replacement chuck does not have to be a Jacobs brand as long as it
is a Jacobs #33 taper mounting, or 33JT, or JT33.

John Cranor
The Jewelry Equipment Dr.


#7

Hi Christine and List…

The “33” refers to the Jacobs Taper size, that it, the tapered hole
in the back of the chuck that you use to mount it…this means that
any chuck with that “33” hole will mount to that machine’s spindle…

Jacobs brand chucks are more or less the standard in the industry,
and they come in several grades of relative precision and duty as
well as size ranges… There are also high quality keyless type chucks
available by Jacobs, Albrecht and others…

Rule of thumb…find the size range and capacity most useful for
you, and get the best grade you can afford…it will be money well
spent…

Gary W. Bourbonais


#8

Now you are talking a language I know! The 33 is a 33 Jacobs Taper
which will usually be abbreviated 33JT or J33. I just pulled out my
MSC catalog (4-1/2 thousand pages and they are happy to send you one
free) and looked up a few part numbers. #98759061 is a Rohm keyless
for $73.18. It is considered an economy chuck, but is made in
Germany. I have a much bigger version and it is a nice chuck.
#08597247 is USA made Jacobs brand keyless high precision for
$176.47. #08502247 is an Accupro for $53.73 which is a "Brand name"
Taiwanese chuck. Normally very nice items for the money. If you go to
the MSC site www.MSCDirect.com you can put the part numbers into the
quick search and see the pictures.

Tim
[Denver CO]


#9

Wouldn’t it be a lot easier to buy a mini-chuck and put it in the
bigger one for small bits? These are available in hardware stores,
or through specialty catalogs like MicroMark or Alsto’s.


#10

Christine, The chuck on your drill is friction fitted onto a tapered
spindle which is a size 33 - this is just a measure of the diameter
and amount of taper of the spindle. If you can get the old one off
and take it with you to a supply house they can most likely match it
up for you if they are not familiar with the nomenclature for sizing
the spindles. Another option, which I use, is to purchase a miniature
Jacobs chuck which is chucked into the drill press chuck. This allows
me to use the smaller size drills with accuracy and if I do need to
use the orginal chuck for something larger I can easily remove the
mini chuck. I’m not sure where I originally purchased mine as it has
been a while, but I think it may have been Contenti’s or maybe
Micromark. Best, Jim DeRosa – James DeRosa, Jr. 140 Clifton Drive
Boardman, OH 44512-1616 330-782-0702


#11

Hi Noel,

I got a wonderful response to my question on and off list, and yes,
buying an adaptor is a great idea. I will probably return the drill
press I have and get another one that I think I like better, although
it’s essentially the same kind of machine, and by an adaptor. I saw
one on the Contenti website; guess I’ll go look at Micro Mark.

Thanks!
Christine