What are these morse taper collets for?

I’ve seen these mt2 collets for sale on eBay...

what do you use these for?

i have ones with a draw bolt to hold work or cutters

but how do these hold things?

Not seen that pattern but I would guess they are to hold parallel-shank reamers or milling-cutters, possibly specific drills, in a tailstock with tang, or (reamers only) a pillar-drill.

They seem to have had a hard life. Two look as they became overheated somehow, while some look badly scarred. I wonder if they had been used in a plain spindle and sometimes allowed to spin badly.

Either that or they are "home-made" and the colour was from hardening and tempering. (Commercially-made collets would be finish-ground.)

Any markings suggesting commercial manufacture?

I have a vague recollection that those are "saver sockets" that allow further use of tooling that has a damaged Morse taper. I can't find any further descriptions of the type at the moment - maybe have something in an older engineering book at home.

Nigel B.

I agree with Nigel except the absence of a drawbar shouts 'drill' at me rather than milling cutter. Drills don't need a drawbar, but milling cutters definitely need to be held secure somehow!

I think they're adaptors for converting small drill tapers to a large taper pillar drill. An ejector wedge is banged in to the rectangular holes to remove drills from the adaptor. I think taper adaptors are expedient rather than best practice - ideally a tapered tool should plug straight into the machine socket to reduce run-out and slipping. (Nigel suggests damage due to spinning - I think that's likely because each converter has two tapers and either could slip due to dirt or looseness. )

Do MT taper shank drills have any advantage in a Model Engineering workshop? I see taper shank drills as quick change devices valuable when lots of pillar drilling of different diameters is done in a hurry. In my lazy workshop, it's hard to beat a keyless drill chuck, and Jacobs only become a nuisance when drills have to be swapped very frequently.

Dave

From the description on eBay i read that they were parallel inside and MT2 on the outside..i presumed that the hole half way up was for helping out a drill or shaft inserted..?

Hi, I was thinking they maybe Retang Drill Sleeves.

However, if they are parallel inside, it counts them out, but I suspect they would hold parallel drills into a taper quill otherwise.

Regards Nick.

Edited By Nicholas Farr on 01/06/2021 10:46:10

Ian, they are for holding parallel shank drills in the sleeve, so you need a dedicated sleeve for each drill size. the drill is inserted just a short way into the slot, and a drift can then be used to eject the drill. I would have thought more handy for production work, one can use a cheaper parallel drill in the sleeve, when the drill is done throw just the old drill away, and you still have the sleeve for another new drill. I would think in most modelers workshops these would not be of much benefit.

SOD, I use taper shank drills quite frequently, especially in the bigger sizes above 1/2" as no chance of the bigger drills spinning in use as they can in a keyless or Jacobs style. I am not a fan of turning the shank of bigger drills to hold the in a drill chuck. If I am making a quantity of anything that requires a series of drilled holes I will use taper shank drills from 1/4" up, I have accumulated a set of metric and imperial taper shank drills over the years. Used ones are often cheap to buy as only folk like us have the machinery to employ them.

Chris Gunn

Split drill driver

Had a bit more of a dig around & found the above link. These also seem to be referred to as "automotive drill" holders in some accounts & appear to require a drive square to be put on the end of the bit, with the parallel bore just to hold them concentric.

The "Use 'em up" repair sockets I initially thought of are not split.

Nigel B.

Can’t quite see the detail but I think they are parallel drill sleeves. When using smaller drills, say under 10mm it is cheaper to use tanged parallel shank drills than morse taper. Used a lot in production drilling setups where you have a taper shank spindle. The shanks are specific for a small range of drill diameter and the drill has a pair of flats on the end of the shank which fits into the sleeve for drive, pushing the sleeve into the spindle grips the drill. Specified them a lot in my design days for multi spindle drill setups. There was a similar question some time ago ( years).

I have a small few long series drill bits, where the blunt end has a stepped pair of flats, much like the tang on a morse bit.
The shanks, seem higher quality finish than conventional drill bits, and may well be harder.
One is stamped HS, above a C in a diamond, above GB, which I assume is the trade mark; the other two are not marked at all, even for size.
I'm guessing they would be ideal partners to these collets.

The colour representation is about correct. The centre bit seems like HSS, but the outer two are noticeably heavier and only weakly magnetic.

Bill

Edited By peak4 on 01/06/2021 12:21:16

From distant memory they are adaptors for holding parallel shank drills which then go into capstan lathe turrets.

Tony

Bill, yes they are used with split sleeves I mentioned, no problem using them in a chuck also. I assume split sleeves are still available from some tooling companies, did find this specification for the drill tang Drill Tnag Dimensions from the USA.

I have a couple of those in MT1 size. They are for holding drills.

These are for holding taps. I have used them in the past at work.

**LINK**

Jim

Peak4, the two odd drills are showing the characteristics of solid carbide. Its a shame they are too long for safely starting a hole in hardened steel. You could try a file on the end of their shanks, HSS would file.

I have never seen the MT holders before, but holding straight shank drills or taps without needing a chuck would be my guess.

The split drill drivers when combined with a taper length drill has the same dimensions as a taper shank drill. They were often used with an automotive shank holder in transfer lines for machining motor blocks, heads, etc. Split drivers are also made for reamers and taps.

**LINK**

These sockets allowed for adjustment to compensate for resharpening drills. The machine spindle had a cylindrical bore with a keyway. There was a grub screw to engage the whistle notch on the holder. A dull tool could be swapped for a sharp one very quickly. The tool and holder were preset to the correct length before being put in the machine.  drills and reamers were always run in guide bushings on the transfer machines.

Edited By John Reese on 07/06/2021 01:50:33

I ended up buying the set of these as i thought they may come in useful for holding taps

however taps wont fit with out making the square much smaller

drills will fit but need a pair of flats grinding

There’s a set from 1/4” to 1/2” in 16th” intervals all made by dormer and all seem to be in excellent condition

Edited By Ian Parkin on 13/06/2021 14:59:26

... and by chance I fall across this:

Mr Pete on centre drill driver

Me Pete aka TubalCain (the American one). He shows a centre drill being held in a split morse taper sleeve, and he mentions that the drill locks when it is partly rotated, which I don't understand.

Bill

Brilliant Bill

thats a great use for my set

Ian, I would presume that they are intended to hold a 'dead size' tool, as the morse taper relies on friction along its length to provide drive. It doesn't have a drawbar, but if driven in (well, gently tapped in) past its nominal size, it will not drive properly. I noticed that TubalCain had some resistance when pushed into the sleeve so presumably sprung to a slighly smaller diameter.

As noted on other occasions, the tang does not provide drive, but is for removing the taper.

Sorry if this is 'sucking eggs' to you.

Bill