Post drill chuck question

[Phutman]

Hi ya’ll I’m new here. Heard somewhere that some of the post drill gurus live here, so I’m hoping you can help me. I recently came into a Champion Forge post drill, I think it’s a No. 110. It came with a 100 year old Westinghouse ac motor. It didn’t come with a chuck at all, and I’d like to put a Jacobs chuck on it. The real problem is that the spindle ends in a 1/2 “ threaded shaft with a crazy fine thread. It’s not 1/2-20, it might be 28 tpi.  I didn’t know there was such a thing. Anyway I don’t know what to do with it, I haven’t seen a Jacobs chuck with more than a 20 tpi thread. I’m going to try attach pics. Any help will be appreciated.

 

 

Edited September 22, 2023 by Mod30
Text size corrected

[LarryFahnoe]

Greetings and welcome Phutman.

I wouldn't qualify as any expert on post drills (I don't even have one), however I thought a bit about your puzzle and then thought to check McMaster-Carr. They have an adapter that might be just the ticket to be able to mount a standard 1/2-20 chuck on that spindle. This site doesn't like links to commercial sites, so go to McMaster and then look for their stock number 92499A243.

18-8 Stainless Steel Male-Female Hex Thread Adapter

1/2"-20 to 1/2"-28 Thread Size

--Larry

[Phutman]

On 9/21/2023 at 5:33 PM, LarryFahnoe said:

Thanks for reading my post Larry, and especially for expanding a few joules of brain energy to come up with your suggestion. Barring someone else’s better solution I think I will go with your suggestion, it should work.

[Irondragon Forge ClayWorks]

Welcome from the Ozark Mountains. If you put your location in your profile, you never know there are quite a few machinists that are members and may be close enough to you to lend a hand. Maybe even make an adapter for you. I have a small metal lathe but don't think it would be large enough to make one.

I can't control the wind, all I can do is adjust my sail’s.
Semper Paratus

 

[Mike BR]

If you find a machinist, one option would be an adapter that's 1/2-28 on the inside and JT3 on the outside.  That way you wouldn't lose working height and wouldn't put extra stress on the quill (though you might have to shorten the threads to take full advantage).

[Phutman]

Thanks for the suggestions guys. Do you think this drill has been modified, can’t imagine that 1/2-28 thread was a thing 100 years ago.

[Frosty]

Before you spend money on adaptors or a machinist, buy a thread gauge so you know exactly what the threads on the quill are and don't waste money and time guessing. The one pictures was about $10 on Ebay and works well for determining TPI, metric versions for "pitch". I determine internal threads by screwing known bolts into the female thread section. If you buy a new Jacobs chuck it will specify the threads and size so the gauge below is all you'd need. If you take it to a machinist  s/he'll have the appropriate gauge. If not find a better machinist.

Frosty The Lucky.

 

  

[Irondragon Forge ClayWorks]

I do believe it has been modified. Here is a couple of pictures of my Champion 102-3 drill presses chuck which I think is original. The original chuck is held to the shaft by a plug in the top hole, that has a flat spot on the shaft. The Jacobs chuck is an addition held to the chuck by a bolt that the original drill would be held in by the bolt.

I don't see any evidence of threads in the shaft looking through the top hole & flat spot on the shaft.

I can't control the wind, all I can do is adjust my sail’s.
Semper Paratus

 

 

[Frosty]

My Champ. 200 1/2 has a slot to drive a wedge and release the chuck. (I believe, I can't think of another reason) This makes me believe it has a taper similar to a Morris taper. I haven't taken it apart and don't intend to either.

Frosty The Lucky.

[Mike BR]

Of course, there's no way to tell when it was modified, or why.  In general, standardization has meant moving from more threads to fewer, so you shouldn't assume anything on old equipment.  Actually you should measure the diameter as accurately as you can, too.  A few months ago I cut a set of 14mm X 32tpi threads, so you never really know until you check.

[Irondragon Forge ClayWorks]

Here is a copy of the Champion catalog #52 1926 if you scroll down to the drills it shows the "never slip chuck" . If you enlarge the page it's readable and the chuck is clearer. Both drills are shown the 100 & 102.

Champion Blower and Forge Co Catalog No 52 1926.pdf

I can't control the wind, all I can do is adjust my sail’s.
Semper Paratus

 

 

[Scott NC]

On 9/22/2023 at 5:49 PM, Frosty said:

Morris

  Morse?  

[Frosty]

Yes, Morse. Stupid spell correct! And I can't shut it off. Spell check a good thing but I hate it when the computer changes words to what it thinks(?) are right. <sigh>

Then again I missed it when I read the post before submitting, Morris is a good word so I saw what I expected. Not only do I have to outsmart the automatic mistake generator in my computer I have to outsmart my own brain! 

Frosty The Lucky.

[Scott NC]

I figured as much but couldn't resist pulling your leg.  .   There's at least one company out there selling morris tapers.  I bet they don't sell much... 

[Mike BR]

Back to the drill press, I noticed that the catalog Irondragon posted said you could request two different chuck sizes or a Morse taper (if not a Morris one).  Conceivably Champion would have threaded an arbor if you asked them to. 

[Frosty]

Some drill bits are morse taper, (have a morse taper shank). 

It's a little known fact that Morse is code for Morris. 

I realize I'll probably never live that down even if it was a spell correct issue and not me so I'm going to have fun with it too. 

Frosty The Lucky.

[Irondragon Forge ClayWorks]

Morris is a vigorous English dance, traditionally performed by men wearing costumes and bells. So suit up and take a video at the anvil to show us.

I can't control the wind, all I can do is adjust my sail’s.
Semper Paratus

 

[Scott NC]

  I'd fork over a fee to see that one.  

[Frosty]

Seems you're supposed to wave things in your hands too, tassels on a hammer and pair of tongs and a few more dancers seems like a good conference activity. 

https://www.youtube.com/watch?v=p84exs2X6dA&ab_channel=ColombeDelons

Frosty The Lucky.

[Phutman]

Don’t want to break up the morris discussion but it turns out that Frosty’s initial advice was best. I made a guess at 28 tpi but once I got a more comprehensive thread gauge, it turns out it’s 24. 

It turns out that 1/2-24 tpi is even more uncommon than 28 tpi. Have not been able to find an of-the-shelf thread adaptor option to go from 1/2-24 to anything normal ( except for guns, but they have a hole in the middle). So, do I look for a local machine shop, or is there a known company on the internet where I can order one. 

[LarryFahnoe]

Good thing you followed Frosty's advice first! I think the local shop is going to be the more likely to be able to make you something that will fit an oddball thread. Mike's earlier suggestion of turning an adapter with a male JT (Jacobs Taper) is a good one. However the cost of a chuck & shop time to make the adapter will add up. You would likely get the best result by bringing the spindle and JT3 chuck in so that the shop can fit both properly.

--Larry

[Scott NC]

  Keep your eye out for a cheap lathe in the future.  Cut your own taper and much more.  Don't wear blinders like others.

[Scott NC]

  I just re-read my comment, I should slow down when I post something.  I was referring to a dissagreement elsewhere, about the blinder thing.  Everybody here is very helpful and I hope nobody took it wrong.  Where's embarrased emoji when you need it.... 

[BillyBones]

Why not just contact Jacobs chuck and ask them if they can help? They have a website and tech support. 

[Mike BR]

I tweaked my taper attachment and needed a project to try it out yesterday, so I turned an adapter that is hopefully good enough to work (with a 3JT chuck).  If you message me with your address I'll send it.  

You'll probably need to buy a 1/2-24 tap and chase the threads.  Not having anything 1/2-24, I measured at 3/8-24 bolt with safety wire and a caliper, then added .125 and used the dimension to cut a gauge of sorts.  I then cut the internal threads with piece of 3/8 hot rolled with a little HSS drill bit puddled on.  So it will likely need to be chased -- and if it fits too loose, there's always locktite, I guess.