found a new way to be hard on my lathe tonite....

[alinwa]

I "know" that a Morse taper recess and tenon are supposed to be CLEAN AND DRY and degreased...... but "knowing" and KNOWING can be different things.

My little Grizzly G4003G has a tailstock chuck which I use a lot. I was making a fixture, drilling larger and larger holes clear up to 1" diameter (TOO BIG for the lathe, the drill bit has a 1/2" shank...) and got too big a bite and spun the chuck a few degrees until it jammed. The end of the taper has a large flattened section which extends into the keyslot to engage the wedge. This flattened section ALSO keeps the Morse taper from spinning.

It's not supposed to. It's not DESIGNED this way. But in the past when I've spun the chuck it stops on the flat and I drill away merrily, all the dumber.

So.....I'm drilling away merrily as is my wont and AGAIN I get a BIG bite, like the whole lathe judders......and the tailstock STOPS advancing. Swoll the shaft out and locked it in the journal.....DUHH!

Took me three hours to disassemble the entire tailstock so that I could carefully tap out the parts and spring everything back without scoring.

Got it.

And promptly relieved ALL my Morse tapers which include the flattened beaver tail section so that THEY ALL SPIN FREELY AS DESIGNED!

I got off easy on this one and learned without breaking stuff.....hallelujah

back to work

a liddle wiser

 

[CMaier]

you are luckie al,
your education only cost you time
this time

 

[JerrySharrett]

I "know" that a Morse taper recess and tenon are supposed to be CLEAN AND DRY and degreased...... but "knowing" and KNOWING can be different things.

My little Grizzly G4003G has a tailstock chuck which I use a lot. I was making a fixture, drilling larger and larger holes clear up to 1" diameter (TOO BIG for the lathe, the drill bit has a 1/2" shank...) and got too big a bite and spun the chuck a few degrees until it jammed.



And promptly relieved ALL my Morse tapers which include the flattened beaver tail section so that THEY ALL SPIN FREELY AS DESIGNED!

I got off easy on this one and learned without breaking stuff.....hallelujah

back to work

a liddle wiser

You probably already know this but the drive tang on a Morse taper is supposed to keep the tapered shank from spinning. A spinning tapered sleeve will eventually score the corresponding surface in the tailstock spindle.

(Did I read this wrong?)

.

 

[Jim Kobe]

I "know" that a Morse taper recess and tenon are supposed to be CLEAN AND DRY and degreased...... but "knowing" and KNOWING can be different things.

My little Grizzly G4003G has a tailstock chuck which I use a lot. I was making a fixture, drilling larger and larger holes clear up to 1" diameter (TOO BIG for the lathe, the drill bit has a 1/2" shank...) and got too big a bite and spun the chuck a few degrees until it jammed. The end of the taper has a large flattened section which extends into the keyslot to engage the wedge. This flattened section ALSO keeps the Morse taper from spinning.

It's not supposed to. It's not DESIGNED this way. But in the past when I've spun the chuck it stops on the flat and I drill away merrily, all the dumber.

So.....I'm drilling away merrily as is my wont and AGAIN I get a BIG bite, like the whole lathe judders......and the tailstock STOPS advancing. Swoll the shaft out and locked it in the journal.....DUHH!

Took me three hours to disassemble the entire tailstock so that I could carefully tap out the parts and spring everything back without scoring.

Got it.

And promptly relieved ALL my Morse tapers which include the flattened beaver tail section so that THEY ALL SPIN FREELY AS DESIGNED!

I got off easy on this one and learned without breaking stuff.....hallelujah

back to work

a liddle wiser

DUHHHH! They all spin freely as designed?

I don't think so, Jerry is right.

Jim

 

[shortgrass]

helps to know what the tang is really for

I don't think I'll go grind the tang off of my taper shank drills and tool holders...... You, also, might consider using one of those handy dandy drilling speed & feed calculators that are on-line. If I'm not mistaken, your lathe is a 12" x 36". Center/spot drill the part and drill the 1" hole (after you've used the speed and feed calculator). On second thought, the speed & feed calculator might not be such a good idea, as you have to know at how many SFM the material you are wanting to make a hole in can be drilled at!

 

[JerrySharrett]

I don't think I'll go grind the tang off of my taper shank drills and tool holders...... You, also, might consider using one of those handy dandy drilling speed & feed calculators that are on-line. If I'm not mistaken, your lathe is a 12" x 36". Center/spot drill the part and drill the 1" hole (after you've used the speed and feed calculator). On second thought, the speed & feed calculator might not be such a good idea, as you have to know at how many SFM the material you are wanting to make a hole in can be drilled at!

SFM is calculated at the point the cutter is contacting the workpiece. For a 1" drill the SFM value used would be at 1".

.

 

[alinwa]

You probably already know this but the drive tang on a Morse taper is supposed to keep the tapered shank from spinning. A spinning tapered sleeve will eventually score the corresponding surface in the tailstock spindle.

(Did I read this wrong?)

.

Let me re-phrase

I NEVER "let" the thing slip......when I say "spin freely" I mean that IF THEY SLIP they should be allowed to spin, not jam.

I was taught that if a Morse taper slips (spins) the correct fix is to STOP, clean everything off and re-seat it because IF IT SPINS it typically dirty/greasy or it's being loaded beyond it's capacity.

I was taught that the flat tang extension was there to facilitate engagement of a wedge or punch and that while it does keep it from spinning it's not DESIGNED that way.

Well. I keep them pretty clean, I swab/wipe the recess fairly often but in this case I'd gotten sloppy and not actually degreased everything but instead wiped clean and relied on the tang to keep it from spinning.

Well, I relied TOO MUCH on the tang flat as it spun, lodged, and then when it tried to spin some more the tang portion wedged the slot open and jammed the shaft into the journal. On inspection I found that the "bearing portion" that the tang rides against is very small and tapered such that it's not capable of withstanding much pressure.

I was taught (again, maybe WRONGLY) that if a Morse tapered shank slips it's BAD, but it's also there to warn you that you need to stop and clean/degrease before you wreck something.

In my case I've two choices........if I'm going to use the flat tang to keep the chuck from spinning I need to machine a small flat support wedge (maybe two of them) to tap into the shaft and give a place for the flat tang to bear OR, because in my case I feel my tailstock is small and fragile, I'll just continue to relieve the tangs so they can't bind up.

But, I'm here to be schooled, thank you guys for your answers!

Learning Every Day

al

 

[shortgrass]

SFM is calculated at the point the cutter is contacting the workpiece. For a 1" drill the SFM value used would be at 1".

.

Different grades of materials are cut at different surface speeds. If drilling common ol' 1018 with a 1" HS drill bit I'd turn (the bit or the spindle) @ about 380rpm. If I was drilling 52100 with that same !" HS drill bit I'd only turn (the bit or the spindle) @ about 190rpm,,,, now, thats on a ridgid machine with flood coolant. If the machine is not real ridgid and there's no flood coolant I'd need to slow down. If she goes to "squakin' " at ya' you're turnin' too fast, and it'll only take a few revolutions to burn the bit. I don't generally drill "pilot holes" unless I just have to, and then the pilot hole is only about the same size as the chisel point of the drill bit. But I'd definately want the tang of the tool holder or taper shank drill bit properly engaged with its socket and the tang has to be in its slot before the taper can engage. From "Machinerys Handbook",,,"Taper Shank Drills (this would apply to taper shank tool holders, also); Those having conical shanks suitable for direct fitting into tapered holes in machine spindles, driving sleeves, or sockets. Taper shanks generally have a driving tang." The tang is not just there for removal of the tool holder or drill bit.

 

[JerrySharrett]

Let me re-phrase

I NEVER "let" the thing slip......when I say "spin freely" I mean that IF THEY SLIP they should be allowed to spin, not jam.

I was taught that if a Morse taper slips (spins) the correct fix is to STOP, clean everything off and re-seat it because IF IT SPINS it typically dirty/greasy or it's being loaded beyond it's capacity.

I was taught that the flat tang extension was there to facilitate engagement of a wedge or punch and that while it does keep it from spinning it's not DESIGNED that way.

Well. I keep them pretty clean.......



In my case I've two choices........if I'm going to use the flat tang to keep the chuck from spinning I need to machine a small flat support wedge (maybe two of them) to tap into the shaft and give a place for the flat tang to bear OR, because in my case I feel my tailstock is small and fragile, I'll just continue to relieve the tangs so they can't bind up.

But, I'm here to be schooled, thank you guys for your answers!

Learning Every Day

al

Good grief Al, are we in different song books? We (me) certinally not on the same page..

To Wit-the male Morse taper has a driving tang sticking out on tools that will have significant torsional load. The female will have a slot to acceipt that tang. I'm wondering if your tailstock even has that slot?? If the male Morse tool shank, with a drive tang, can spin when it is seated in the tailstock then that part was not properly built.



..

 

[alinwa]

Good grief Al, are we in different song books? We (me) certinally not on the same page..

To Wit-the male Morse taper has a driving tang sticking out on tools that will have significant torsional load. The female will have a slot to acceipt that tang. I'm wondering if your tailstock even has that slot?? If the male Morse tool shank, with a drive tang, can spin when it is seated in the tailstock then that part was not properly built.



..

Yup...... this tailstock is too short to have a dedicated female slot, it's drilled completely thru in such a way that the corners of the male drive tang just barely catch the ledge formed by the drift key slot. There is no dedicated female slot to accept it. Basically the hole through the middle where the drive screw runs is nearly as large as the drive tang, and you can look clear thru the tailstock shaft like a telescope. When the Morse taper slips under torsional load, the drive tang wedges the drift key slot open and jams it.


The design is slick in that when you run the tailstock quill clear in, the end of the drive/lead screw impinges on the drive tang and pops the tool free but it doesn't leave much of a ledge for the drive tang to set on.

EDIT....according to this wiki the flattened tang IS NOT there to accept torsional loading...... this wiki is more in line with my 35 yrs-ago schooling.....

https://en.wikipedia.org/wiki/Machine_taper

 

[shortgrass]

Oh! I 'd definately believe Wiki before I'd believed Machinerys Handbook! (sic) The interdnet is never wrong!

 

[Jim Kobe]

Yup...... this tailstock is too short to have a dedicated female slot, it's drilled completely thru in such a way that the corners of the male drive tang just barely catch the ledge formed by the drift key slot. There is no dedicated female slot to accept it. Basically the hole through the middle where the drive screw runs is nearly as large as the drive tang, and you can look clear thru the tailstock shaft like a telescope. When the Morse taper slips under torsional load, the drive tang wedges the drift key slot open and jams it.


The design is slick in that when you run the tailstock quill clear in, the end of the drive/lead screw impinges on the drive tang and pops the tool free but it doesn't leave much of a ledge for the drive tang to set on.

EDIT....according to this wiki the flattened tang IS NOT there to accept torsional loading...... this wiki is more in line with my 35 yrs-ago schooling.....

https://en.wikipedia.org/wiki/Machine_taper

During my apprenticeship more than 50 years ago we ran some pretty hefty machinery. All had the slot in the tailstock for the tang on the drill, some drills up to and over 2". Now, when drilling a 2" hole into a steel plate with a 4" radial drill, if the drill stopped and the spindle spun, you snapped off the tang and got a kick in the ass from the foreman. The "slot" in the spindle, whether drill or lathe spindle was for keeping it from spinning, not just for knocking it loose.

 

[cloudrepair]

Alinwa a method I used when I got a drill with the morse taper that had to short of a flat or sheared off flat was to put a Allen wrench in the back of the slot so my drift key would gain that last little bit of purchase and pop it loose. It always works if there is something left that the drift can get a hold of. I have run some big machines.
Big face mills and spade drills can make trouble to

 

[alinwa]

Oh! I 'd definately believe Wiki before I'd believed Machinerys Handbook! (sic) The interdnet is never wrong!

You're proclaiming your ignorance on the interdnet......the Machinery Handbook (22nd edition) is one of the quoted references. Listed at the end along with many others

 

[TRA]

You're proclaiming your ignorance on the interdnet......the Machinery Handbook (22nd edition) is one of the quoted references. Listed at the end along with many others

All common tapered tooling has a drive slot, tang, or dog. Even a Bridgeport has a drive in the spindle. They are all there for the same reason and that is too keep the tool holders, collets or adapters from spinning. You never operate a machine with that gizzy missing, if you do, you can destroy a spindle real fast.

BTW the taper is there only for accuracy, not for driving the tool.

 

[shortgrass]

You're proclaiming your ignorance on the interdnet......the Machinery Handbook (22nd edition) is one of the quoted references. Listed at the end along with many others

I think it is you that has shown ignorance, Al. After all, you're the one who jammed the drill and ended up spinning the tool holder in the socket, messing up the socket in the process. Might try reading a book instead of checking with the interdnet for a change. I've got several different editions of Machinerys Handbook, from edition #5 printed in 1915, to edition #24, they all say the same thing, word for word. It's no wonder you're "oft' dissed". Good luck with your hacking.....

 

[Pete Wass]

No Tang holder

I noticed with my "New to Me" 12x36" Chinese lathe the tail stock Quill does not have a slot for a tang to register in. This one was spun and galled. I took it to a machine shop that has Morse Taper reamers and they chased it out for me. I filed down the arbor that had spun but ordered another with a new keyless chuck, which came in today.

Thinking about it, I don't think my SB has a tang slot in it's tail stock quill either. Do some lathe tail stock quills have than slots? I was wondering if, perhaps some set screws or some other device could be fitted to hold the tang? But then, how would one disengage it?

Pete

 

[alinwa]

I noticed with my "New to Me" 12x36" Chinese lathe the tail stock Quill does not have a slot for a tang to register in. This one was spun and galled. I took it to a machine shop that has Morse Taper reamers and they chased it out for me. I filed down the arbor that had spun but ordered another with a new keyless chuck, which came in today.

Thinking about it, I don't think my SB has a tang slot in it's tail stock quill either. Do some lathe tail stock quills have than slots? I was wondering if, perhaps some set screws or some other device could be fitted to hold the tang? But then, how would one disengage it?

Pete

Hey Pete,

If you have good fit and keep it clean it shouldn't ever spin and certainly not gall. Galling comes from prolonged abuse.....I've slipped mine a few times but it's un-marked. I've slipped it because I'm too lazy to degrease it and insert it correctly I was just wiping the male end clean with paper towel and inserting it into register. Using the "seat" which isn't really a seat..... Mine does have a slot, just enough to make you line it up to register but not enough to hold it. And, the real reason mine slipped is because I was using a very sharp 1" drill bit with only a 1/2" shank. This combination means that if the drill bit starts to dig too deep (I'm feeding it by hand and I like to make as big a curl as possible, keeps the bit cooler) it starts to bog, the small shank flexes, I back out and it pops free which causes chatter. Chatter is death on a Morse fitment. Also, this was my first run thru SS and it cut different than CM I'd used prior. I later did some 12-L-14 "Leadloy" and it cut like a snowplow on asphalt throwing 6" of powder...

I didn't damage anything at all. I did learn a free lesson which in my case led me to eliminate the potential for problem by grinding off the whale-tail on my chuck. I did the same work yesterday with NO tang lock and no failure of any sort. Just fed a liddle slower, took 30 seconds more to run the holes (I'm making oversized barrel tenon locknuts) knowing that if it DID slip it'd free-wheel not jam.

I don't think there's enough meat on these small quills to make a solid seat, at least there's not on mine.

 

[JerrySharrett]

.

Thinking about it, I don't think my SB has a tang slot in it's tail stock quill either. Do some lathe tail stock quills have than slots? I was wondering if, perhaps some set screws or some other device could be fitted to hold the tang? But then, how would one disengage it?

Pete

If you have an American made South Bend lathe it WILL have a tang retention slot in the tailstock spindle.


.

 

[coyotechet]

Jerry are you sure about the South Bend having a flat in the tail stock spindle? I have 3 American made South Bend lathes and close friends with South Bend American made lathes and all of them have a straight thru hole of the tail stock spindle. (9a's, 10K's, 10L's, 13's inch)

Chet

Below is pictures of a spindle out of my Heavy ten which I replaced with a n.o.s. hardened spindle. All but the 13 inch use a no. 2 MT with out a flat tang. The 13 inch has a no.3 MT no tang.