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View Full Version : I know what it is, but I dont know exactly what it is...



cuemaker
10-01-2011, 11:18 PM
When I purchased an old SB lathe, I got the original owners tool box. There were over 75 taps (a good portion new and unused) and about 50 drill bits. Out of the drill bits, a serious majority of them are sizable but with a taper.

I dont know much about tapers, but after Googling part numbers, tapers and measuring, I still dont know.

Picture is an example of a new Cleveland Twist drill bit, made in the US. 9/16. The calipers show the length of the taper, and 1st picture is the width at the top of the flat part.

What taper is it?

http://i201.photobucket.com/albums/aa129/xringx/DSCF0095.jpg
http://i201.photobucket.com/albums/aa129/xringx/DSCF0094.jpg

sch
10-01-2011, 11:31 PM
Looks like MT2 taper to me, after eyeballing a few of my taper drills.

cuemaker
10-01-2011, 11:37 PM
Ohhh gosh, I hope not (because I will look stupid).... but really hope so...

I thought I tried to put it in my tailstock and it was to small.

What is the flat spot for?

EDIT>>>>>>> It is swallowed up by my tailstock which is a mt2

gwilson
10-01-2011, 11:37 PM
Looks like a #1 to me. That is only a 9/16" drill.

J Tiers
10-02-2011, 12:18 AM
Looks like a #1 to me. That is only a 9/16" drill.

Measurements are about a MT1 indeed.

length is different due no doubt to a somewhat longer overall length..... my MT1 are about 2.14 to the same point on the tang, but it is common to have extra length when the drill or arbor diameter is larger than the MT at fat end.

0.451 is about right for "about there" on an MT1.

cuemaker
10-02-2011, 12:31 AM
I measured and measured.. but didnt fit into the MT 1 based on what I read for "max" this and that.. so I thought maybe something exotic... But my call a friend option says MT 1, so thats what I will be going with..

Next question.. is the flat spot for a set screw?

EddyCurr
10-02-2011, 12:55 AM
I dont know much about tapers

It is swallowed up by my tailstock which is a mt2

Looks like a #1 to me.You may or may not be aware that 'Steel Drill Sleeves' to adapt
a 1MT shank to a 2MT bore are readily available and inexpensive.

An off-shore brand at Travers is less than $10, a Collis is less than $30.
The MSC & Enco sites are offline at the moment, but their prices are likely
similar.

.

toolmaker76
10-02-2011, 12:58 AM
I have not seen that flat spot on drills before, but I have noticed my Sheldon lathe with MT2 taper does not have anything inside to keep the drill from spinning. I have thought about putting a setscrew on the tailstock to keep larger drills from spinning.

It hasn't been much of a problem to date, but I have some work coming where I am going to need to uses some larger drills. I am wondering if that is some sort of provision for the same thing.

On most machinery I have used to date, there are flats in the tailstock that grip the flats on the tang, preventing the drill from spinning.

EddyCurr
10-02-2011, 01:03 AM
Nor have I, but I don't get out much.

In any event, isn't the flat spot far enough up the shank to be at or beyond
the end of a tailstock or a sleeve when the drill is seated? If this is the case,
perhaps it is intended to assist with removal.

.

Jaakko Fagerlund
10-02-2011, 01:35 AM
If your Morse taper drill bit rotates in a Morse taper, then there is something wrong with the taper in either the holder or the drill bit.

Forrest Addy
10-02-2011, 02:33 AM
Might be a #5 B&S. I dont know about that funny flat. It's ramped against the taper. Maybe for a set screw to hold the drill in the socket?

Is the taper about 1/2 per ft and the taper lenght 2 1/8" there abouts. It wasn't unusual on B&S tapers to extend the big end if needed to legthen the tool.

Has to be an oddball but recent. Look at the poly packaging tube. No bar code so it can't be TOO recent.

We used to have some old close quarters tooling that shaks like Jabobs tapers but has an integral flat. WW II era. Very handy. I used some of it for out of the way, tucked in behind drilling on a missle mount back when I was skinny and flexible.

rohart
10-02-2011, 06:34 AM
If you're still in doubt about which taper it is, you need to measure the angle accurately.

Taper tables should specify the angle of each taper, but if you only have the e 'taper per length' specs, then you have to convert this to the angle.

You measure the angle best by mounting the drill in the lathe, centre to centre, and using a DTI mounted at centre height in the tool post.

Manufactured tools can vary in length, but the angle has to be correct for the taper.

I agree that the flat could be for either a drive pin or a removal cam.

As for the flat on the end, called a tang, the discussion about whether it is meant to help drive the tool or not will go on forever, but it does look like a Morse taper tang to me.

jugs
10-02-2011, 06:45 AM
When I purchased an old SB lathe, I got the original owners tool box. There were over 75 taps (a good portion new and unused) and about 50 drill bits. Out of the drill bits, a serious majority of them are sizable but with a taper.

I dont know much about tapers, but after Googling part numbers, tapers and measuring, I still dont know.

Picture is an example of a new Cleveland Twist drill bit, made in the US. 9/16. The calipers show the length of the taper, and 1st picture is the width at the top of the flat part.

What taper is it?

http://i201.photobucket.com/albums/aa129/xringx/DSCF0095.jpg
http://i201.photobucket.com/albums/aa129/xringx/DSCF0094.jpg

I'm not getting a picture :confused: :confused:

boslab
10-02-2011, 09:33 AM
there was some 'anti spin' mt drill sleeves about, they had a grub screw to stop the spin, this might be one of these, i only saw an example of one in a metalwork class.
just an idea
mark

cuemaker
10-02-2011, 09:57 AM
Jugs,

The pictures are massive (I like really big pictures), but here i a link to my photo bucket so you can see them..

http://i201.photobucket.com/albums/aa129/xringx/DSCF0094.jpg
http://i201.photobucket.com/albums/aa129/xringx/DSCF0095.jpg

Mark McGrath
10-02-2011, 10:05 AM
Most British makers used to stop No1 morse at 17/32",then 2 morse to 7/8",3 morse to 1.1/4" although there was one that went to 1.5/16".
The flat on the shank is called a whistle notch and it`s for security if you use the drill in an automatic.Stops the turret going back leaving the drill in the job.

J Tiers
10-02-2011, 10:27 AM
As for the screw to hold the drill solid in tailstock......

This is probably a bad idea.

The issue is that the ultimate "holder" of the drill is not the tailstock ram, but the little pin or key that keeps the ram from turning.

No matter what sort of heavy clamp you hold the drill to the ram with, that little key is all that prevents rotation. Even a decent square key can be 'rolled over" is a bad jam-up. The "key" in a tailstock is often a drastically reduced size to fit in the assembly, far smaller than the key a similar sized arbor would have. That small key with limited depth in eitehr part is vulnerable to 'rolling over" and jamming up the ram. Or it may be just a little "pin" about 2 or 3mm diameter, ready to shear right off, or cut into the ram keyslot..

The best way to handle larger drills is to clamp a 'dog" to the drill shank, and rest the tail of the "dog" on the compound, or on a bar that you clamp to the compound or elsewhere. That way the tail can stay sullorted as it moves in and out, and the twisting forces are not transmitted to the little bitty key in the tailstock.

While Mr Fagerlund is correct that the taper should hold, that tends to fall flat when the drill is larger than the taper..... the leverage is such that the taper WILL spin, so external holding means is advisable.

About the tang holding...... I don't want to start a debate, the "tang drive" one is never-ending, but ........... If the tang were *really* intended to hold against turning, it would be at the FAT end like on a CAT taper, where the leverage is best. and not at the thin end where the tool has the mechanical advantage.
I have seen numerous tangs sheared off when defective tapers failed to hold......

Toolguy
10-02-2011, 11:10 AM
The notch is called a whistle notch. It's for a setscrew to hold it in the taper. Some end mills have this also. You would not likely have a setscrew in your lathe tailstock. This is probably to hold the drill in an MT adapter for a radial drill press or an adapter for a mill spindle. If you have to change tools a lot or trying to hog out a hole to make time on production a big setcrew would be an advantage to keep the drill in the holder and not twist off the tang. The tang is usually considered to help in removing the tool from the taper, although it will drive the tool if not overloaded.

jugs
10-02-2011, 11:29 AM
Jugs,

The pictures are massive (I like really big pictures), but here i a link to my photo bucket so you can see them..

http://i201.photobucket.com/albums/aa129/xringx/DSCF0094.jpg
http://i201.photobucket.com/albums/aa129/xringx/DSCF0095.jpg

Thanks for that - thought I'd gone blind :cool: :D

As mark says

The flat on the shank is called a whistle notch and it`s for security

Commonly found on milling cutters, less common on MT stuff