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The South Bend (dinged) Quill Comparison

graham-xrf

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Hi machinist folk
I am finally getting into cleaning up and discovering the condition of my (now two) South Bend lathes. One is a 9C, picked up for a crazy price ($147 equivalent) a couple of years back, and more recently, a 9A for a bit over $500, because I wanted the QC gearbox and power cross-feed apron.
Also, to some extent, I need each to help fix the other.

I this company, I guess we are used to seeing pictures that make us feel, well.. "not-so-good", but I am thinking I should be looking for a repacement quill for the 9A. If there are some that are available because they have been "parted out", because of some event that made the whole machine unviable, like it "got dropped" or something, then that is OK, but a good many "parted out" bits are now actually the just leftovers from the machine having donated it's best to another.

The $147 South Bend 9C is the "better" one. It looks like it has had the easier life, cared for, and somebody loved it enough to fit a replacement ACME thread bronze nut to the rear of the quill.
I have not yet inspected and measured up the truth of these machines, but at least there is no obvious wear ridge in any of the ways, and things do turn and move.

The quill from the 9A is a different scene. It has the usual dings, but also has had some powerful, deliberate, off-centre event take out the first 122mm (0.48") of the Morse taper.

Surprisngly, the MT2 chuck taper still "sticks" into the remaining deeper part of the quill taper.
The 9C MT2 taper grabs the chuck normally, though the inside looks as if it could do with a little careful reamer clean-up.

I post the pictures for comment and advice. These are early days in the fixup attempt. The time I can post more tasteful pictures seems right now hard to imagine, but I am bound to try!SB-9A & 9C Quill Nut side.jpgSB-9A+9C Taper side.jpgSB-9A+9C Taper side2.jpgSB-9A + 9C Quills Compared.jpgSB-9A Quill-MT2 view.jpgSB-9C Quill MT2 view.jpg
 

graham-xrf

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Oops - sorry folks.I did not know the pictures would display all over the posting.
I just clicked "Insert Image". I guess there is a better way to do it.

Re: the abused quill. Is this the sort of thing one might contemplate "making a new one"?
For the slot, I do have a friend with access to a milling machine.
 

Latinrascalrg1

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Wow what caused that kinda damage to thr inside of that quill? It looks like someone tried to drill it out to a larger size for some reason!
 

SLK001

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Oops - sorry folks.I did not know the pictures would display all over the posting.
I just clicked "Insert Image". I guess there is a better way to do it.
That's the way it SHOULD be done. Plenty of pictures to help visualize what you are saying

Re: the abused quill. Is this the sort of thing one might contemplate "making a new one"?
For the slot, I do have a friend with access to a milling machine.
It's good practice at your machining skills. The second hardest part will be the left hand ACME tapping or single point threading of the spindle. The hardest part will be the MT#2 taper in the bore, because you will need it concentric with the lathe axis and it is too large to fit inside a 9" spindle for support. If you know someone with a lathe with a larger bore, it is doable on that lathe.

Or, you could just live with the "drilled out" version.
 

graham-xrf

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Wow what caused that kinda damage to thr inside of that quill? It looks like someone tried to drill it out to a larger size for some reason!
Good question Latinrascalrg1. It surprised me too. Looking as if the tailstock was low, and a bit to the side. You can definitely see it was "off centre". Clearly deliberately drilled or bored. Ignorance? Carelessness?

Maybe it was the end result of drilling out a broken off or damaged taper seized in there hard. Still hard to imagine! Amazing that it still "works" with the remaining part of the MT2 taper further down. This, of course, is then without the support of a properly engaged Morse taper all the way.

Sadly, I have to chalk this one up as junked - and try to find or make another one. There is at least one YouTube video of making a quill from scratch, but I am not sure about attempting it. The question is .. how many used tailstocks does one have to buy from (say) eBay before ending up with a decent quill? The descriptions just say "used", and the pictures are not normally close and clear enough to guess at the condition. Also, you end up with a chunk of unwanted (worn?) tailstock.

Perhaps the exception is this one. What means "Very good original condition"? A bent ACME shaft and rusted up quill? $159.99 + another $104 to ship to the UK. I think I give this one a miss!

I am leaning towards the idea of trying to make one. Even through some possible fails, I can use the experience, and I get the right part in the end.

Maybe use a salvaged old car axle, or piece of hydraulic ram? I don't know. What sort of steel is in a quill anyway? Does it get heat-hardened at any point? These things must be somewhat "turnable", because folk can and do do bore out the back end and fit a new bronze ACME thread upgrade, like in the 9C picture.
 

Latinrascalrg1

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Could you properly boar out the rest of that ruined quill so that you can plug it and then reboar the mt taper you desire on the inside?
 

SLK001

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Maybe use a salvaged old car axle, or piece of hydraulic ram? I don't know. What sort of steel is in a quill anyway? Does it get heat-hardened at any point? These things must be somewhat "turnable", because folk can and do do bore out the back end and fit a new bronze ACME thread upgrade, like in the 9C picture.
Old car axles are usually harder than a whore's heart. I assume that a hydraulic ram would be too. However, you could easily anneal them for your use. Standard quills were not heat treated, but a hardened and ground quill was available as an option. Neither of yours appear to be hardened. South Bend used a lot of leaded alloys (41L40) in their production because it machines so well. If you can make the needed setups securely on your lathes, then you could fab one on one of your machines.
 

graham-xrf

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South Bend used a lot of leaded alloys (41L40) in their production because it machines so well. If you can make the needed setups securely on your lathes, then you could fab one on one of your machines.
Good to know about the steel - thanks for that. Regarding setup capability, One lathe came with a whole bunch of extra tooling and stuff, including two sizes of 4-jaw chuck.

What is the norm with using such steel? Does it usually come heat treated already? Do we use the annealed versions, then heat it up a bit in an oven? Yeah - I know! Us guys would usually try and recycle some nice steel picked up for a song from a scrapyard!

The internet advertisements offer ..
41L40 HT (Heat Treated)
41L40 Mod (Modified)
41L40 QT (Quenched & Tempered)
41L40H HT
Wow!
 

SLK001

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You want the annealed version. Over here, it is CFA (Cold Formed Annealed) - you could also use one of the non-leaded versions. A 9" is way too light to try to machine a hardened product. Plus, your setups are going to be iffy, at best. For instance, how securely can you hold your blank in a 3 or 4 jaw chuck? How far does your blank stick out? Can you hold the end securely enough to be able to turn to size, then drill thru? Do you have a left-hand ACME tap, or are you going to single point thread it? Do you have an MT#2 reamer (you can get a fairly decent set from China for less than $25US).
 

graham-xrf

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You want the annealed version. Over here, it is CFA (Cold Formed Annealed) - you could also use one of the non-leaded versions. A 9" is way too light to try to machine a hardened product. Plus, your setups are going to be iffy, at best. For instance, how securely can you hold your blank in a 3 or 4 jaw chuck? How far does your blank stick out? Can you hold the end securely enough to be able to turn to size, then drill thru? Do you have a left-hand ACME tap, or are you going to single point thread it? Do you have an MT#2 reamer (you can get a fairly decent set from China for less than $25US).
OK SLK100. Many thanks for the advice, especially on what not to use. With some help, I think I can get there.

The rescue lathe need not be one of the South Bends (which are mine). I do have colleagues who can provide access to bigger lathes (eg. 400mm with a big steady), which could be used.

I do happen to have a #MT2 cutter and a reamer, not yet used, put on the shelf by the guys who should have ordered #MT3 at the time, and it ended up in a disposal box. I simply asked for it, and they handed it over.

As for the ACME nut part, I am not sure how long it needs to be, but I had thought that one could use a brass or bronze nut from a catalogue, or eBay. When I looked in eBay (UK version) I found this from USA.

I mention it just an example. The ACME nut is $22.80, and the shipping cost is $19.92, and you get a chunk of leadscrew not directly usable. I would likely not go for that deal, and keep looking, but my point is that using a replaceable ACME nut is an reasonable idea that need not break the bank. There seem to be enough sources for ACME nut bushings. The task becomes to copy the nice insert job on the 9C quill.

A minor stumble is to get the right measurements. Are there such things as dimensioned drawings of South Bend lathe bits? I am measuring "differences" between the 9C and 9A quills. Maybe the 9C is a re-make already!
I won't bore you with the detail - just wondering if the slot is supposed to be 11/64" wide (9C) or 3/16" wide (9A).
 

SLK001

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A minor stumble is to get the right measurements. Are there such things as dimensioned drawings of South Bend lathe bits? I am measuring "differences" between the 9C and 9A quills. Maybe the 9C is a re-make already!
I won't bore you with the detail - just wondering if the slot is supposed to be 11/64" wide (9C) or 3/16" wide (9A).
Your best bet will be to do all the dimensioning yourself from the part you want to replace. Things changed over the years at SB. IIRC, the thread for the screw is 7/16"-10 ACME LH, but it's been a while since I had a 9". Again, check yours to be sure. A tap of that flavor can be had for less than $40 (but that is "here" and not "over there"). A 1/2" - 10 ACME LH would be easier to get for you - AliExpress has them and will ship to UK. You should use a tap to put the thread in if you're not confident in your bit grinding or threading cutting capabilities, but don't force it to do all the work. Pre-cut the thread with a single point cutter to about 85%, then finish with the tap. The pre-cut thread can be pretty sloppy, which will get cleaned up with a pass of the tap.

As for the slot, measure your key and add 0.003-0.005" for the slot - remember, things changed over the years at SB.
 
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