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Old Dunlop Drill Press - I need a chuck

Gazz

Stainless
Joined
Sep 7, 2004
Location
NH
I have an old Dunlop drill press - a small bench top unit that is excellent condition. It is currently equipped with an ancient keyless chuck which I am not to fond of. I would like to get a jacobs type key chuck for it but there is a problem. The spindle is threaded 1/2-24 and I haven't been able to locate a chuck with those threads. Other than taking the thing apart, welding up the spindle and then cutting and rethreading to 1/2-20 which I really do not want to do, does anybody know of key type chuck that has those mounting threads?
 
Would you lose too much carriage travel by making a stub adapter to fit one to the other? If you did all of the lathe operations in one go it would be nice and concentric.

Were I you I'd drill and thread a blank the size of the chuck back to 1/2-24, then turn a stub on the back of it to the right size for 1/2" threading, then part off.

Thread it 1/2-20 and Bob's your uncle, and with no modifications to any of the precision bits.

Alan
 
Gazz -

Sounds like an exact copy of my Dunlop bentop DP. Mine is gold colored, 4-speed step pulley, but has a keyed Jacob's chuck. Probably 1950 - 1960 vintage.
 
No offense meant but if you use that method you will notice that the method of "and Bob's your uncle, and..." will result in a drunken uncle Bob..and hiz caddywhompus adapter thingie...

There are only 2 ways to make that... as he said BUT you must chase the 1/2 thread to fit the chuck at the same setup as when you made the internal thread. Sounds hard or imposssible? not impossible just real hard to do.

Sooooo...

Make the part with the internal thread to fit your spindle thread. If it were me and I did not have good threading experience, I would take the spindle out of the drill press to use as a gage while making the threaded hole. If I had good threading skills, I might try it without using the spindle as gage. underline MIGHT...

Now that you have that fit correctly, take another pc of material and make a plug on which you will make a thread just like the spindle. You might ask why not just use the spindle? Well, you MIGHT be able to do that IF you can bore soft jaws, and or hold the spindle in your lathe using a Adjust True Chuck.. Ya got one of those??? Didnt think so... So make the plug with the spindle thread, and NEVER TAKE IT OUT OF THE MACHINE.

Now you screw that part you made with the internal spindle thread on to the plug in the lathe...

Now you make the thread to fit the chuck you want...

ohh... one more thing... dont use just any soft steel, use a prehard, 4130 is nice that is most likely 28 -32 Rc and your adapter will last a long time.

If all the above is too much like trouble...

SKIP IT AND LIVE WITH WHATCHA GOT NOW...
 
I was looking at the press this afternoon and had the same thoughts about making an adapter. There is quite a bit of threaded spindle since the keyless chuck used a lot to tighten up on. So if I made an adapter, there shouldn't be any reason why I couldn't cut off 1.5" or so from it and maintain some amount of working room under it. The big problem would be cutting the internal threads as Gary E has mentioned. Rather than take the spindle out, I think I would just keep cutting threads until I made one that fit nicely. Actually, why couldn't I make a short piece of threaded rod that would mike the same as the spindle and use that as a gauge?

When I'm finished with that job, I need to make a quill stop as I want to use this for drilling gun barrels and receivers to mount scopes and sights.
 
So you want to use this for a lite gunsmithing / scope mounting duty....I dont know the machine you have but I have mounted more scopes than you can imagine. Use that drill press ONLY IF IT IS VERY RIGID.. if it's a little shaky, forgit it and buy something rigid, STRONG is what you MUST HAVE, no flimsy allowed. You also should have a way to hold a barrel and action in alignment ON THAT DRILL PRESS... can you? A bridgeport is ideal.
 
I almost didn't understand the issue..... Until I realized you wrote 1/2-24. Sounds typical of Dunlap stuff, same thread as some of the little 109 lathes.

Can you take it out, turn it down, and re-thread to 3/8-24? That's pretty common, and what you intend to do with it is not exactly drilling bridge steel. The 3/8-24 is plenty strong for most work anyhow.

I think I might be leery of welding on it, due to certainty of warpage, even though you intend to clean it up afterwards and re-thread....
 
This probably a 12" drill press from 1935-45, made for Sears by Atlas and sold as Dunlap. I used to have one. Model 101.03580, I think.

The 1/2-24 thread used to be almost universal with large eggbeater drills, like breast drills. Most of these little DPs were sold with the chucks designed for those drills. Jacobs actually _did_ make a large geared chuck for this thread (I had one) but it hasn't been made in years.

If you were looking to preserve the historical aspect, I'd get an old Millers-Falls breast drill and steal the chuck off it. If you wanted to be modern, I'd thread the spindle for 3/8" and use a 1/2" chuck sold for use on portable 3/8" drills. Keep mind that these little drill presses were sold for 1/4HP motors, so don't try and drill anything too massive.

I'd personally try to keep it original, and sell it to buy a newer one. This is a very old drill with bronze bearings and a rather lightweight frame. Some collector's value, too.
 
John in MA wrote

>This probably a 12" drill press from 1935-45, >made for Sears by Atlas and sold as Dunlap. I >used to have one. Model 101.03580, I think.
snip..
>I'd personally try to keep it original, and sell >it to buy a newer one. This is a very old drill >with bronze bearings and a rather lightweight >frame. Some collector's value, too.

I have a 101-03582, and it has a decal on the front that says SKF ball bearing equipped. Didn't know I had a collector's item :)

Looks like the one at:
http://owwm.com/PhotoIndex/detail.asp?id=1737
Only complaint I have is that I need more height. I have an X/Y table and when I put that under it, there's no room. Was thinking of making an extention.

Got mine for $65 and it came with the mortising attachment. He even threw in a Craftsman dovetail jig.
 
if its a keyed 1/2" jacobs type chuck then why not just take a thread mounted type that has a 5/8" 16tpi and thread bush it down to 1/2" 24 tpi thats how i have fixed spun tappers on a drill press or two :D
 
This is a little 'out of the box' but what if you slathered JB Weld inside a 1/2-20 chuck body, then drilled and rethreaded to 1/2-24? You should retain enough virgin steel to hold the torque from the spindle and the epoxy will help preserve the thread profile. This retains the originality of the drill press and you can always reinstall the old chuck if you ever want to sell it in the future.
 
I thought the headroom was small, also. Mine was raised another 12" by removing the hollow tube and replacing with a solid, round bar, turned to correct size.

Had trouble releasing & tightening the table clamp (handle too close to the column) so it was extended out another 3".

Not a bad little DP, often used for a quick, noncritical hole. A full size mill or mill/drill would be a better choice for sight work, IMO.
 
Steve, the 03582 is bigger and heavier, and as you say had ball bearings. I have one too. Also should have a tapered spindle.
 
My father had the same drill press and the same problem. The chuck screwed up and down the threaded spindle with these spring loaded jaws inside the body.What a peice of crap. I took the spindle out,center drilled it and single pointed 1/2-20 over the top of the 1/2-24. We then abused it daily for years. My son now has it and is still trying to break it.
 
Gazz,

To cut internal threads to match your spindle, the best way would be to get a 1/2-24 National Special tap, which is available for under $5, plus shipping:
http://www.sjdiscounttools.com/han1446.html

You can make a bushing adapter without using a lathe.

This is how I would try to make a bushing adapter, from 1/2"-24tpi to 5/8"-16tpi (as suggested by 1yesca):

1) Screw a 5/8-16 bolt into a chuck with that thread and cut off the end of the bolt almost flush with the back of the chuck.

2) Tighten the chuck jaws down onto the bare threaded spindle of the drill press so that the chuck is upside down.

3) Put a center drill in a vise on the drill press table, and run the drill press to make a hole in the bolt that is now in the chuck. Gradually increase the diameter of the drill bit until you get the tap hole size for about 50% thread. This ensures that your hole will be close to centered.

4) Put the tap in the vise and thread the inside of the hole, turning the spindle pulley by hand to drive the tap.

***************************************

Another way, if you use a taper mount chuck, would be to tap a hole into a piece, put that onto the spindle, thus converting the drill press into an upside down vertical lathe. Use a flat file to cut down the JT33 taper stub. This might be tedious.
 








 
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