How to determine a drill press spindle profile to move to a threaded chuck spindle

Hello,

Please excuse me if the subject is too simplistic for this forum. I want to learn how to ID the spindle profile on a drill press so it can be replaced by a threaded spindle.

Thanks for reading my post.

Julien

Julien43 said:

Hello,

Please excuse me if the subject is too simplistic for this forum. I want to learn how to ID the spindle profile on a drill press so it can be replaced by a threaded spindle.

Thanks for reading my post.

Julien

Click to expand...

To what end ?

or

Why ?

Burgmaster turret drills are the only industrial grade drill presses I have seen that use threaded chucks. I trust that their designers had a good reason, specific to their complex spindle design. Machine designers in the USA have generally chosen to use spindles with Morse tapers or Jacobs tapers on drill presses, even the less robust home shop grades.

There were some very cheap models that had long 1/2-20 male threads and a really poor keyless chuck. That was how I would describe my first drill press, bought new in 1954. I was very happy to get a far better machine with a 33JT/locking collar spindle in 1962.

Larry

the taper dimensions (likely Jacobs taper) can be found in a quick search of the internet. however, age, region of manufacture and brand all play a role as to what taper your machine may actually have as there are many taper types out there. you can also try searching your exact machine. also spindle shafts are usually somewhat complex and not worth the time (and material) needed to machine one Unless your spindle is damaged badly already. another thing to consider is that a threaded chuck has a couple of drawbacks, one is that it renders the spindle non reversible ( screws off the chuck), not normally a problem on a drill press, but in the event of a stuck tool it can be. I've also had poor luck with accuracy with threaded chucks being that the jaws are not aligned with the spindle center or are at a slight angle to spindle center.

Julien43 said:

Hello,

Please excuse me if the subject is too simplistic for this forum. I want to learn how to ID the spindle profile on a drill press so it can be replaced by a threaded spindle.

Thanks for reading my post.

Julien

Click to expand...

Im not sure exactly what you're trying to do, need more info.
Are you trying to determine the internal spindle taper?
There are adapters that will fit in your existing spindle with threads on the end for attaching a chuck...is that what you want?
Also, have you googled the model of drill press you have to find the specs on it?
MT2 is common on floor model drill presses, benchtop machines often have MT1. And some cheap machines dont even have a removable arbor, and only have a male jacobs taper for attaching chuck.

APD said:

Im not sure exactly what you're trying to do, need more info.
Are you trying to determine the internal spindle taper?
There are adapters that will fit in your existing spindle with threads on the end for attaching a chuck...is that what you want?
Also, have you googled the model of drill press you have to find the specs on it?
MT2 is common on floor model drill presses, benchtop machines often have MT1. And some cheap machines dont even have a removable arbor, and only have a male jacobs taper for attaching chuck.

Click to expand...

my first drill press a craftsman floor model 150 i think it was had no chuck and a bent spindle so what i did was to cheek were the bearings and pulley set for run out then straighten it and were the chuck tapper was i threaded it to 1/2" x 20 tpi and bushed it to 5/8" x 18 and installed a Jacobs threaded chuck at times i had up to 10 other drill presses at the same time but that was my go to drill press in never let me down

Assuming that by "spindle profile" you mean the shape of the area of the spindle that effects the mounting of a chuck, there are two general possible types of taper that may have been used. And, of course, there have been threaded mounts, but those are fairly rare on drill presses.

The first thing you need to do is remove the present chuck. If it is attached with a taper, extend the spindle and look on it for a pair of slots on opposite sides for a taper key to remove the chuck along with it's taper adapter. If you have those slots, you need to get the appropriate taper key to remove the chuck. If your spindle does not have slots, then you would generally use a pair of wedges that are designed for this purpose. They are U shaped with the tapers on the two legs of the U. You place them on opposite sides of the chuck, between the back face of the chuck and a shoulder on the spindle. When the wedges are brought together the chuck should pop off. Be ready to catch it. The keys or wedges can be obtained from McMaster or most machinist supply companies. There are only a few sizes of each so selection should be easy.

With the chuck removed you can then see if you have an internal or an external taper on the spindle. An internal taper will be evidenced by a hole in the spindle and it will most likely be one of the Morse Tapers. If, instead of a hole in the spindle, there is a stud that fit inside the chuck, then it is an external taper and very likely a Jacobs taper.

There are tables for the sizes of these tapers. You can find them on the internet and in machining reference books. You will need a caliper to measure the diameter at the end(s) of the taper that you find.

The internal, Morse taper can be measured by taking diameter measurements of the taper on the chuck adapter that will still be attached to the chuck. Compare the measurements to those in the tables for Morse tapers and you will have it.

The external taper can be measured on the spindle and then compare the measurements to those for Jacob's tapers.

There you have it.

But I can not for the life in me understand why you would want to convert a drill press to a threaded chuck. Threaded chucks are OK for hand held drills, but are not very accurate. And taper mounted chucks are a lot more accurate and, easy to change if the drill press is set up for that. Good quality chucks are available with Jacob's tapers instead of threads and you can purchase a chuck adapter that will convert the Jacob's taper in the chuck to whatever Morse taper that may be in the spindle. Or, if it is a cheap drill press with a Jacob's taper on the spindle, you just buy a chuck with the matching Jacob's taper and it will fit. My floor stand drill press uses a Morse taper mount and I have two chucks that I can use on it as needed. A key is used through a slot in the spindle to easily remove the chucks when I want to change them.

If you are looking in hardware stores for a new chuck, DON'T. Go to McMaster of a machinist supply and get a good one instead of the cheap, threaded ones.