Morse Taper problem

[gehutch]

Hi folks, I hope somebody can help me with a problem I am having with my morse taper in the tail stock. I have an elderly Sears (Atlas) 12 inch lathe with a #2 taper in the tail stock ram.
Here is the problem: When I use a large drill (1/2" or bigger with a MT tail) the drill will turn as soon as I put on a little pressure with the drive wheel. I have looked into the ram with a flashlight and I cannot see anything that will hold onto the MT flat tail. There is no groove in the ram to hold a split piece and the drive screw turns at its face so the spade cannot fit into anything to hold it.
What am I missing? I have been holding onto the drills with a big Vice Grip. Ugly looking setup.
Thanks in advance,
Gordon

[Richard Wilson]

Hi folks, I hope somebody can help me with a problem I am having with my morse taper in the tail stock. I have an elderly Sears (Atlas) 12 inch lathe with a #2 taper in the tail stock ram.
Here is the problem: When I use a large drill (1/2" or bigger with a MT tail) the drill will turn as soon as I put on a little pressure with the drive wheel. I have looked into the ram with a flashlight and I cannot see anything that will hold onto the MT flat tail. There is no groove in the ram to hold a split piece and the drive screw turns at its face so the spade cannot fit into anything to hold it.
What am I missing? I have been holding onto the drills with a big Vice Grip. Ugly looking setup.
Thanks in advance,
Gordon

Assuming that both the tailstock barrel and the drill shank MTs are clean and free from burrs and scores, next time you fit an MT drill, lock the tailstock down, and feed the drill hard against the end of the workpiece with the spindle stationary. This seats it in firmly. It works for me with larger drills. if the barrel and shank have scores and burrs, you've no chance until you've cleaned them up. A 2MT reamer for the bore, an oilstone or diamond hone for the shanks. Just enough to get rid of the upstanding ridges.

Richard

[drysdam]

By incredible coincidence, I may know the problem. I also have an elderly Sears lathe, although a different model. Just this morning I was reading about the tailstock and found that the nominal #0 MT is not genuine:

http://homeshopsupply.com/mt.htm

Maybe your Sears lathe isn't a true #2 and therefore your chuck isn't being held firmly.

[SGW]

I don't think lathe tailstock tapers typically have a slot for a drill tang. They rely only on the taper to hold.

You can probably improve things by cleaning up the taper with a #2 Morse finishing reamer. You don't have to take off much, just enough to knock off the dings and nicks. I clean up the taper on my lathe about once every 5 or 10 years, it seems.

[TGTool]

I don't think lathe tailstock tapers typically have a slot for a drill tang. They rely only on the taper to hold.

You can probably improve things by cleaning up the taper with a #2 Morse finishing reamer. You don't have to take off much, just enough to knock off the dings and nicks. I clean up the taper on my lathe about once every 5 or 10 years, it seems.

I changed that on my Atlas by measuring location down the tailstock quill, then drilling and tapping two opposite holes that now hold set screws protruding into the quill to hold the tang. I can remove them if need be since I sometimes find a taper shank without flats that won't seat properly.

This has been sufficient to hold the drill chuck that holds large (1-1/4") Silver and Deming drills though it's probably more than the lathe was really designed or expected to do. If I get too enthusiastic with the large drills it will stall the lathe to the point where the belts slip.

But the screws keep the drill chuck from spinning.

[PeteM]

Clearing chips or peck drilling can commonly pull out a drill in gummy materials.

Even with the tapers in pristine condition, I'll commonly use a sort of custom-made lathe dog to keep a MT drill or a chuck from spinning in the tail stock.

The Atlas lathe isn't particularly rigid or powerful; so I'd be inclined to step drill up to about 5/8" and move to a boring bar after that.

[Iraiam]

I have had this problem on a couple different lathes, my solution on a 10" lathe with MT2 tail stock was to use a plastic dead blow hammer to seat the bit, I have drilled holes up to 7/8" like this, and can take 2 hands on the tail stock wheel to break the taper loose again.

I suppose if your taper is worn though, it just won't seat strongly.

On a larger lathe I run on occasion, the tail stock is MT4 (I think), the tooling is usually big and heavy enough to get a good grip on while wearing gloves, and forcefully seat the taper without any other tools.

[DATo]

This is pretty radical and I don't know if it would be something you'd want to attempt but if the tailstock spindle isn't hardened (and I don't think it is) you might try locating where the tang of the #2 would be located down the length of the spindle and then either drilling and tapping a hole perpendicular to the flats of the #2 in line through the centerline of the spindle and then using a couple of set screws, one from either side, to clamp the tang in place; or, drilling and reaming a hole for a dowel pin at 90 degrees to the spindle and offset from the centerline such that the line of tangency of the dowel pin would be along the face of the tang. This second solution might involve a bit of air grinding to the face of the drill tang to get a good fit. The dowel wouldn't necessarily contact the tang, just be close enough to keep the drill from rotating. If I were faced with this problem I might make a model spindle from aluminum to test the theory before committing to the actual part.

[hareng]

Every lathe i have ever had or used has had some sort of lockup for the tang. Inserting the tang it has to be rotated, once found i pull out and ram it in.

If the tailstock ram is an ejector you might be able to make something up or adjust.

[J. Randall]

Every lathe i have ever had or used has had some sort of lockup for the tang. Inserting the tang it has to be rotated, once found i pull out and ram it in.

If the tailstock ram is an ejector you might be able to make something up or adjust.

Well, they must make them different over there, because here any lathe I have ever had or used has not had a provision for the tang to lock into, the Morse taper in good condition should not need any assistance .
James