Lathe help

[wesley]

Hi all am in need of help with my southbend lathe a 14 1/2" - 16" my problem is the taper in the spindle nose ,want to fit mt tooling in it ie collet chuck can any one help out here with the size etc or is a member willing to make me one ,more than happy to cover costs,there was a firm in the states selling them at one point but the cost when they had one was very high,am happy to do the internal mt taper in fact if l could get blanks would do one in mt2 and mt3, hope a member can help me out ,even had a look to se if there was a gauge that you put in the bore then you could copy that if that makes sense but am still learning this game.

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[Hopper]

You could make your own. It will be a standard taper of some sort. Probably Morse. But you could set your lathe up to make your own easily enough. Set a small dial test indicator gauge on the toolpost and set it to run on the rear side of the taper in the spindle. Adjust top slide until the gauge reads 0-0 as you wind the top slide back and forth. This is your angle to turn the blank plug.

Put the chuck on the lathe and use the set topslide to turn a blank that is a bit longer and a bit larger than you need. When it gets close to the measurement of the large end of the taper in your spindle, take the whole chuck and job off and test the taper in the hole in the spindle. Take more cuts if required. Repeat. Keep carriage locked in position throughout.

Once you have made the plug, tap it into position in the hole in the spindle then drill and bore and possibly ream the MT2 or 3 hole in the middle. This will probably require setting the topslide to a new angle for MT2 or 3. This can be done by mounting a taper-shancked centre between the tailstock centre and a piece of bar centre drilled in the chuck. Use the DTI reading trick again to set top slide angle.

A good turning exercise for you.

 

[goldstar31]

I think that the taper will be No 2 or 3 Morse anyway but the Bible for most lathes is
Lathes.co.uk.

Google it, identify your machine and read up the wealth of detail for it.

You COULD buy a cheap No 2 and 3 pair of centres as test items- and probably use one of them to cut correct tapers.

Check that your spindle is not hardened or you will ruin a good taper reamer! as you might have to clear burrs etc in the tailstock and perhaps in other tooling, too.


As Hopper says, tapers are quite basic practice.

Hope this helps

Norm

 

[Technical Ted]

Here ya go:

Ted

 

[wesley]

Well many thanks to you all ,will settle down and have a go at making it from the info l now have,but will get there in the end ,so thanks to you all.
wes

 

[goldstar31]

As you think the taper is nether 2 ir 3MT, I would make a mould with car body 'bodge' and measure the results against the chart from South Bend.

The release agent ideally is polyvinyl alcohol but candle wax or oil might do.

Interesting, isn't it?

Perhaps you should be looking a Jarno and other 'less standard' tapers

Good Luck

Norm

 

[goldstar31]

A re-read of Geo Thomas's bit on tapers suggests that many older American lathes used Jarno tapers both in the spindle and tailstock.


Googling further-B&S certainly used Jarno so check for a standard Jarno taper

N

 

[nel2lar]

You might find a little bit more info in this document from South Bend Lathe.

 

[packrat]

Not sure what you are asking but my old South Bend catalog lists the 14 1/2" lathe with a Morse Taper No.3
capacity through the spindle 1 3/8". collet capacity 1 1/16" {that would be a 5C collet} .
Do you have the threaded spindle nose 2 3/8-6 or the cam lock D1, South Bend also made a long taper L00
spindle nose, but all have the same Morse Taper #3..

 

[wesley]

Hi packrat my spindle is 2 1/4" x 6 and l wish it was mt3 but its not,never mind we will get there with.

 

[wesley]

Well l am going to give hoopers way ago and norms way to se what l have and also was thinking about spraying wd40 up the spindle bore then putting a thin say plastic bag up it then filling that with expanding foam and se what that turns out like,you have got me going now ,will keep you all posted.

 

[Technical Ted]

Hi packrat my spindle is 2 1/4" x 6 and l wish it was mt3 but its not,never mind we will get there with.

I think you will find that it is the same taper per foot as a #3 MT, but with a different diameter (between a #3MT and #4MT). That is what the chart I posted shows for a 16" lathe. My 15" SB is the same and I made one for it using the dimensions from the chart. It works fine and cost me nothing since I had a piece of material on hand to use for it.

I used a test indicator to set my compound to the same angle as the spindle taper (0.6024" taper per foot). I set my compound to turn so the big end of the taper was on the tail stock end and the small end on the chuck end. This way my compound was all set for cutting both external and internal tapers. I turned the OD to the size specified on the chart and while test fitting it in my spindle taper was happy to find it fit great! Then, I inserted it into the spindle taper to bore the ID using the same compound angle setting since it was set for a #3 MT angle from turning the OD. .

Ted

 

[Technical Ted]

Just thought of another step I didn't include in my previous message. Before inserting the adapter into the spindle to bore the ID I made a tiny witness mark on my spindle where it wouldn't interfere with anything with my die grinder. Also marked the adapter. Aligning these witness marks every time you insert the adapter will help keep things running true when you have an older lathe like you and I and the spindle bore may not be in perfect shape. I also removed the adapter and re-inserted it, like I would during use, just before the finish pass. I felt this might relieve some of the stresses that might have developed during the rough boring.

It runs very true.

Ted

 

[clockworkcheval]

Maybe a small add-on, when I make a taper I relieve the middle part so it sits on the small diameter and the large diameter but there is no chance of wobbling on the middle diameter.

 

[goldstar31]

Maybe a small add-on, when I make a taper I relieve the middle part so it sits on the small diameter and the large diameter but there is no chance of wobbling on the middle diameter.

Yes but no one has established what taper exists and once established, I would get both a roughing reamer and a finishing one.

We wait -with baited breath- to all important final answer
Norm

 

[wesley]

Well a update on the taper,l did not have a small dti to get down the bore of the spindle,so went for norms ( filler bodge ) as he calls it ,well its came out better than l had thought it would ,so we have a taper 1.325 down to 1.176 the southbend data sheet that ted put up says it should be that to start,so now its time to make it now ,but before l cut that ,need to play about with a back plate so l can fit a smaller 4 jaw chuck on the lathe,have a really nice 4 jaw but its so dam heavy ,and as l will need to take the chuck off a few times to check the fit in the spindle with the part still in the chuck ,time for a smaller one,but will give update soon as l can.
wes

 

[Technical Ted]

Here's a thought: The SB data sheet states it's the same taper as a MT #3, but different diameters. So, how about if you were to chuck up on and indicate in something with a #3 MT (like a large drill bit or even a Jacob's chuck with a #3 MT shank, etc.) and use a dial indicator on that to see how you line up for taper with the compound? If you indicate it in closely (both the drill (or whatever) and indicate the taper in with your compound, you should be able to use it as a setup guide. This should prove to minimize actual testing it in the spindle taper. And if you are lucky like I was, eliminate the need for more than one, final test to verify it is correct!

Ted

 

[wesley]

Good thinking ted,l will get a better set up with a proper mt3 taper ,the mould l made was good but not like a smooth taper,but can still use the mould as a ref as l turn,good old norm the filler trick will come in handy again l bet ,thanks to every one for there time and help,hope to get the chuck done tomorrow ,then turn taper day after,then will report in .
wes

 

[goldstar31]

Wes
Glad to be of help. Actually, my late wife was the second Lady Fellow of the Royal College of Surgeons of Edinburgh and this was approximately her way of taking and teaching making dentures. Now our daughter is doing much the same stuff.

Me, I was just a copier really.

Don't be looking for canaries in the sparrow flock. Look for the simple way.


Cheers

Norm - now in his 90th year

 

[goldstar31]

Anyway, a bit of me. Morse tapers WERE based on the 10"bar sine and the difference from one end of the triangle was a quarter of an inch.
It was all lovely school boy trigonometry made for you know for 14 year olds until some not so bright lathe operator couldn't measure ten inches and worse, his errors became standard.

So you will make a rough almost exact taper thinking ten inches and a quarter difference in the radius and therefore half an inch in diameter! Simple!