South Bend Drill Press Spindle Taper Help

[pago cruiser]

Was getting tired of the lateral play (everywhere) and offset at full extension with my 15 YO Craftsman, so I picked up a SB drill press a several weeks ago from local CL. 3rd owner, who bought it from the son of the guy who bought it originally in Chicago; I'm a sucker for chain of custody stories...
It had next to zero lateral free play at full extension, but the runout was considerable.
The Spindle protruding from the head was 0.003", but the Chuck Body was 0.011, and 2" further down the shaft of a NOS 3/4" Hansen bit the runout was 0.019." You could literally see the wobble.

Finally found a USA made Jacobs 34 JT2 replacement on ebay, and removed the Chuck, expecting to see a 1/2" Jacobs 2 taper.

Instead, I found this: See pics.
Looks like the taper was cut with an axe. It's also a really funny size. O.658" (???) on the big end. Measured at 0.631" on the small end of the Spindle Taper.
The Chuck is so loose, it rattles in my hand like castanets. "Jacobs Chuck #34, Hartford Conn, Made in USA." If you look closely at the Taper Pic, it also appears the Chuck has been slipping on the taper. I have not noticed that in the few times I have used this in the last couple weeks.

Assuming my google link was correct:
A JT2 Taper is 0.4876" small end and either 0.5488" for a short taper or 0.5590" for a standard big end.
A JT3 Taper is 0.7461" small end and 0.8110" big end.

So what the heck happened here? Did someone just make up a taper size and machine both the Spindle (crudely) and the Chuck to match?
If so, how did the taper manage to get BIGGER than a JT2?
More importantly, how do I fix this? Been looking at ebay for SB spindles for a couple weeks. Nuttin. Nada. Zip.

I typically drill things and cut things and weld things and grind things. If I need things machined I have some folks that I trust to do those things when they come up. Obviously, this is either a "replace the part" or a "machine the part" fix. As the "replace the part" option appears a dead end, can this spindle ...maybe...be machined to a new JT2 Taper? Or???

Dang. Buy an older drill press, they said. Much better made, they said. Easy to repair, they said...
Sigh.

 

[mogandave]

Probably a Morse taper.

Pictures?

 

[tombell572]

Pictures didn't show up for me.

Tom B.

 

[mogandave]

Git choo a:

 

[pago cruiser]

Dang. Not sure what happened. They might have been too large a file size. I'll try again with a reduction in size.

 

[mogandave]

Are you sure that does not come out?

 

[RoninB4]

Semi-retired machinist/toolmaker here. The taper does look a bit ugly but pitting due to corrosion should not be considered ruined as long as it doesn't cause "bulging" to stand away from the rest of the taper surface. Tapers are a unique and somewhat fascinating thing (ok it's just me) in that if two components are properly mated they will "lock" but if withdrawn by just .0015 the lock vanishes and the components are easily disassembled. Ok, it's the nerdy toolmaker in me that finds that fascinating.

There have been a large number of tapers used in the machine tool industry over the years. Jacobs, MT, Morse, B&S, CAT, BT, and Jarno are just a few of the more popular tapers that have been in use. They are all different and the mix is of primary concern when purchasing used machinery. Some older machines even have proprietary or impossible-to-find tapers. Why did this happen? Everybody thought they had a better idea for the application and tapers evolved as machine design evolved. It's even worse when it comes to tool holders and collet systems. A taper should fit exactly and have ZERO wobble if it fits properly. The fact that you detect some misfit (castanets?) shows that you have mismatched machine tapers. Your search shows different numbers? That's also because you're searching for the wrong taper.

Can yours be re-machined? Yes it's possible, anything can be made. Would I do it if I were you? Absolutely not. A taper only works if the tapers match EXACTLY, even the slightest mismatch would result in the taper not locking/holding because your machine doesn't employ a drawbar. I have several industrial machines capable of doing this, measuring instruments to determine the amount of taper, loads of experience, and I would still be hesitant to change the taper for several reasons I won't go into yet. Ask why if you want to but the details will bore you to death.

What I would suggest is that a matching drill chuck taper is still out there and probably readily available. You have a drill press, not a vintage jig borer so the taper is not a particularly specialized application. What you need to do is to measure not only the diameters of the large/small end, but also the distance between those diameters. It's important to have all the numbers recorded as accurately as possible, three decimal places (.***) would be best. The diameters are easy enough with a dial or digital caliper. Clean with alcohol, then put some black magic marker on the taper and LIGHTLY scribe a small, thin line/mark on the taper (lightly so you don't kick up a burr). Take the reading at both marks and them measure the distance between. Use magnification if possible to get accurate numbers. This will determine the amount of taper and help identify which one you need. If you're having trouble identifying which taper it is just post or send me the numbers, I have enough references to identify it. The pitting should NOT be removed with a file or any coarser abrasive, it will ruin the ability of the taper to lock. We'll discuss how to remedy this in another post. It's fairly easy to ruin the taper when doing this by hand with too coarse a grit paper. Post what you find and we'll go from there.

 

[Whitworth]

Usually on a drill press that age and size, the taper is J33.

Don't know much specific to South Bend, though.
Do know parts are rarer than hen's teeth.

Taper may have been shortened, causing chuck to bottom out before seating.

 

[11b30b4]

This may help. http://www.jacobschuck.com/uploads/ueditor/file/20200604/1591238129286207.pdf

 

[pago cruiser]

Thanks all for the responses.

morgandave - pretty sure it is not a Morse Taper, as SB offered an optional Spindle with a Morse 2 taper. See attached pic "SB Accessories". Mine is the "Spindle J, with short taper". Why the heck that Taper was not defined is a question for the ages.

RoninB4 - great detailed response. I confirmed my dims, and here is what I have:
Big end Taper = 0.658", Small end Taper = 0.631".
Distance between the two = 0.941".
Based upon these dims, the closest Jacobs Taper would be a No. 6, at Big end = 0.676", and Small end = 0.6241". The length also seems to match pretty well, at a nominal 1.0".

I followed your lead, and (short of laying this out in autocad) found an online taper calculator. Using my dims, the taper works out to an angle of 0.8228 degrees, at 0.028723"/inch. See attached pic.

Unfortunately, based upon another Table I found that included angular dims (see pic "Jacobs Tapes with angles", my taper angle does not match the Jacobs #6 angle indicated at 1.4868 degrees. But I think something is off. The Big end/Small end/length dims cannot be so close (my measured vs the table data) but the calculated angle is off by about a factor of 2. Multiplying my calculated angle by 2, I get 1.6456 degrees; close to the table data of 1.4868 degrees; but this should be a lot closer. The Taper/inch values (Table of .0519") and mine of (.658-.631 = .027") is also off by about a factor of 2. I cannot reconcile this.

Whitworth - I checked the JT33, but the dims don't match. My big/small diameters are 0.658/0.631, while the J33 taper big/small is listed at 0.5605/0.6240. Don't think the Chuck is bottoming out. The Spindle engaged taper is 0.941", and the taper within the Chuck measures at 1.085".

11b30b4 - Thanks. I confirmed that the Taper Table I found matches the Jacobs dims.

Note: in reference to my reply to morgandave above, within the "SB Accessories" attached pic, the "Spindle J" description includes a further reference to a "CE1201 Jacobs 34 Chuck". A search for the "CE1201" yielded a SB Lathe that was for sale on the Practical Machinist site a few years ago. And that clearly indicates a 6T33 Chuck - albeit with a Morse taper attachment. See pic. But in the first pic (SB Accessories) it clearly indicates a Jacobs 34 for the CE1201 part number.

I can find a 34-06 (which kind of match my dims), and a 34-33 (which do not appear to match my dims as closely).
I can also find a 6T-33 Chuck.
I am not sure a Jacobs 34 Chuck can also be a 6T33 Chuck.
There is seemingly bad info out there, but I cannot figure out what is correct and what is not..
Sigh.

Could anybody with a SB Drill Press who has replaced their Chuck chip in??? I may start PM'ing folks with the SB drill press I guess.

I have a call into Jacobs (which is now apparently owned by the Apex Tool Group), but the guy I needed to talk to was not working on Friday. Not sure what they can offer, but figured I'd try.

And another 2 hours go by...

 

[Whitworth]

My best guess would be you've got a J6 taper that's worn/scored up.

Jacobs 34 refers to the model of chuck, the numbers after refer to the taper, example; Jacobs 34-33 means J33 taper, and Jacobs 34-33c means J33 taper with thread-on collar. J6 should be Jacobs 34-06. (I think)

Looks like you need it reground, or if that not feasible, there's enough material left to resize it toJ33 taper.

 

[pago cruiser]

Thanks Whitworth; that is the best assessment I can come up with as well.

But it baffles me how South Bend literature can indicate a Jacobs 34 correlates to a CE1201, and then in other docs indicate the CE1201 is a 6T33. There is not on 6T-33 Chuck on ebay; and the 33 Taper dims do not match my Taper or Chuck.

Guess I'll find a 34-06 on ebay and try it. And later sell the Chinese and the NOS US made 34-02 I found locally...
The buggers on the taper appear to be less than 10% of the taper area; so I think it should engage sufficiently. My machinist friend also suggested to just take the taper down to a J33; although RoninB4 seemed to feel that was probably a last resort. It is beyond my skill set, but the friend I have makes parts for military boat drones, so I would ...think... he should be capable of matching taper specs.

That said, still not sure what to do about the .003 runout on the Spindle. May pull it and take to the same friend with a lathe and try the flame straightening trick. Saw some UTube videos, and it looks promising. Probably more promising than finding a NOS Jacon Spindle for sale, or having a machinist just make a new one... There's a couple South Bend DP beaters on ebay right now for crazy $; but no guarantee about spindle runout...

I did finally give up this am and cross-post a much shorter version on the Practical Machinist site; no answers yet. There are a plethora of South Bend DP owners over there; hopefully one will chip in. I am still dumbstruck that this question has not been raised and answered several times in the past...

 

[RoninB4]

It is beyond my skill set, but the friend I have makes parts for military boat drones, so I would ...think... he should be capable of matching taper specs.

That said, still not sure what to do about the .003 runout on the Spindle.

I did finally give up this am and cross-post a much shorter version on the Practical Machinist site; no answers yet.

-Your friend "should" be capable of accomplishing this IF he/she is familiar with the process(es) involved with mating a tapered spindle. I indicated that this should be considered a last resort due to the time/labor involved, even for an experienced toolmaker. Getting the exact taper spec'd and ground may still require spotting (for contact surfaces) and lapping to achieve proper fitment. It's not as easy to do as it appears to be. Not knowing your facilities or skill level I didn't want my post interpreted as something the average suburban homeowner should attempt and it not ending well. I don't like to lead others into disasters.

Your spindle runout depends upon whether the spindle is contained by bearing or bushing. Yes it could be bent but something worn out is a more likely cause than a catastrophic impact like a tip-over. Bent would have some evidence remaining at point of impact. Not saying bend didn't happen but a careful inspection is in order before chasing a guess.

Entirely possible that the spindle taper has been altered by each previous owner. With older machinery it's not uncommon to find misguided solutions a PO decided to do to get it running again. Even with molds/dies, that were worked on by people that should know better, I'll find cross threaded fasteners, poor workmanship, and flat out geometrical errors needing correction. If "skilled labor" can make bad choices in a professional setting I have to expect that I'll find a surprise on every piece of machinery I encounter. I'll check your numbers after I've had enough coffee (!) and report back, I'm just not awake enough at this hour of posting.

Didn't know you were on PM, I've been a member for many years. Sometimes a very cranky bunch but a great collective body of knowledge in the membership.

 

[Whitworth]

That said, still not sure what to do about the .003 runout on the Spindle. May pull it and take to the same friend with a lathe and try the flame straightening trick. Saw some UTube videos, and it looks promising. Probably more promising than finding a NOS Jacon Spindle for sale, or having a machinist just make a new one... There's a couple South Bend DP beaters on ebay right now for crazy $; but no guarantee about spindle runout...

If you haven't already, please check out www.owwm.org for info and to post a wanting to buy message in their buy/sell forum. They are loaded with knowledge and experience.

And these guys specialize in refurbishing drill press spindles, www.hammerscale.com

 

[RoninB4]

Update:
I've searched on-line as well as through Machinery's Handbook (20th edition) and am a bit perplexed. MH has all the dimensions for common machine tapers. I was less concerned by diameters-to-lengths as the only critical dimension is the taper itself. So I calculated the taper per inch/foot from the numbers supplied and found nothing close enough in a taper commonly used in production. A #6 Jacobs is close but not close enough to be self-supporting/locking. There are plenty of machines utilizing a unique taper, especially in specialized vintage machinery/tooling. That doesn't really apply here as it's a Craftsman drill press that would have used an off-the-shelf drill chuck. I don't like the conclusions I'm going to list, no offense is intended.

1) Dimensions given aren't correct (I do this too)
2) Somebody did a re-work to the spindle taper and did a horrible job of it for whatever reason

Both are easily confirmed or dismissed. Have a good look, under magnification, at the taper surface. I realize it's a bit corroded but the unaffected surface should be a nice ground surface and look like it. A multitude of circular scratches going around the tapered surface are an indicator of someone altering the taper and trying to make it smooth again. A ground surface should look much more uniform than anything done in a lathe/mill. Even attempts at polishing usually reveal the thin/coarse lines that haven't been polished out. If it appears the taper has been altered and you're certain the numbers supplied are correct then you may have little choice but to re-cut the taper.

 

[pago cruiser]

Thanks for the responses guys. Much appreciated.

RoninB4 - The measurements are the best I can obtain from my tools; a 10 year old digital micrometer and a new Harbor Freight dial indicator.
I am also ignorant of some potential South Bend machine dependent decisions made decades ago. I.e., my dim on the small end of the taper varies by .01 from the listed small end for a #6 taper. I can consider that pretty close for my crude-ish tools. But on the big end, my measurement is off by (.676 - .658) = .018". Almost double, but for all I know SB decided to provide the space for the wedges by eliminating the top part of the taper. And as you indicated earlier, this is a production machine; so (assuming) that no one has buggered this in the previous 5 decades... a #6 Taper would seem the best...fit. I have ordered one last night on Ebay; will compare to the Chuck I pulled off as well as the spindle and post back.

I'll also get the taper as clean as possible and inspect - I'm assuming I can use some emory cloth on this, as long I am not too aggressive?

Whitworth - Thanks for the info on OWWM and Hammerscale; was not aware of those groups. Good to know that there is Plan B for Spindle refurb.

As this DP does not appear to have been tuned up in its life, I will also change out the bearings and re-measure spindle runout before assuming the Spindle is bad enough to require mechanical deformation intervention.

In related news... I read in a post on (I think) the Hobby Machinist site where someone opined that the Jacobs Chucks made in USA literally had that engraved into the chuck body. And the Chinese flavors say "JACOBS USA". I did confirm this with the 2 Jacobs MT2 Chucks I bought. The Amazon version was etched "Jacobs USA" and the ebay NOS version was engraved "Made in USA".

However, for the JT6 chuck, both the "new" and the "Vintage" chucks seem to both have the same "Jacobs USA" nomenclature. The box for the "Vintage" JT6 chuck does however match the box for my earlier purchased "Made in USA" JT2 chuck; and that chuck says "Made in USA".

I have attached pics for the Jacobs "Vintage" JT6 chuck box as well as the nomenclature engraving.

Can anyone confirm if the "Made in USA" or "Jacobs USA" story is accurate?

Thanks again for your responses.

 

[WAS Jr]

Smaller South Bend lathes had a truncated Morse 3 taper in the headstock. A Morse 3 would fit, but stuck out. It’s possible the DP has something similar. I’d be amazed if a shop would redo the taper on that size drill press, but Bubba could have got at it, thinking he was going to ”improve” things.
I’d ask on the South Bend forum over at Practical Machinist.
Those drill presses, like all South Bends, have quite a following so I would think hard before I started hacking away at it.
Bill S

 

[Whitworth]

Speaking as a non-machinist, it looks pretty obvious that a chuck spun on the spindle shaft sometime in the past. Once that happens mounting a chuck becomes more problematic and it just keeps happening.
It's ruined many nice drill presses, and it's a shame 'cause the South Bend is a really nice looking machine.

 

[pago cruiser]

WAS Jr - I have posted over there yesterday, but there has not been a SB DP owner response; tough crowd to noobs, I guess.

Whitworth - I agree, it is a great looking DP; and once tuned up, I expect it to outlast me... I'm still bummed that the PO was...perchance...less than honest in his ownership/use story. However, maybe he just never knew.

I sent an email off to the Hammerscale folks. A pretty impressive website. Amazing what they can do. Thanks for the link; I'll advise how this turns out.

 

[pago cruiser]

I sent some pics to a the Hammerscale guy in NC, and (short version) he indicated that the taper damage appears significant enough that my options are:
a) regrind down to a #33, assuming there is enough material un-galled,
b) build up the taper with weld and then regrind, or
c) make a new spindle.
d) the least likely option would appear to be sourcing a NOS or used spindle; like searching for a unicorn...

I'll get mine off and send it out in the next couple days.
Bummer.

 

[RTM]

I sent some pics to a the Hammerscale guy in NC, and (short version) he indicated that the taper damage appears significant enough that my options are:
a) regrind down to a #33, assuming there is enough material un-galled,
b) build up the taper with weld and then regrind, or
c) make a new spindle.
d) the least likely option would appear to be sourcing a NOS or used spindle; like searching for a unicorn...

I'll get mine off and send it out in the next couple days.
Bummer.

Crud, nothing like an expert taking all the wind out of everyone’s sails.

Good luck.

 

[mogandave]

Good luck with it, and keep us posted.