MT 4 1/2

In need of a MT 4 1/2 adapter for my Harrison 140 - looked for ages on the net for one to turn up but as its such a stupid incomprehensible size seems impossible to find - I'm still trying to work out why Harrison used such a stupid size the 140 -but can't do much about it.....

I'm going to make my own as a project so was wondering if any had done tis and any tips or tricks... ?

The opening paragraph of this explains the why : **LINK**

http://www.edproject.co.uk/MT45adapter.html

… and he then proceeds to describe the how.

MichaelG.

Something I thought about a little while ago as my lathe uses this taper.

A company I approached seeking to have obsolete collets made is D&J WORKHOLDING they offered to make me obsolete collets for £50 each, they may well make you one but as to be expected with one off orders won't be cheap, they are very good to deal with, I have purchased things from them in the past.

There must be hundreds of lathes with MT4.5 headstocks, and when they pass from industry to private hands the adaptor bush always seems to go missing, probably because it is only used for between centre turning so is kept in a cupboard somewhere. An opportunity for Ketan to get a batch made?

Rather than complimenting Harrison on their forward thinking, for giving you a lathe with the smallest taper that will accept the ubiquitous 5C collet, you curse them. Surely, your ire is better directed at the previous owners who have misplaced the bush.

The 'explanation' in the link above is rather wishy-washy and the 5C reason has some sound engineering behind it.

If you have Harrison on your naughty list, you can add Boxford (11-30) and Colchester (Chipmaster) to it. As these lathes have the same spindle taper, bushes may be available from them. See:

https://www.model-engineer.co.uk/forums/postings.asp?th=87430

and the 600 Group website.

If you have any US connections, the bush is available from Grizzly:

https://www.grizzly.com/parts/grizzly-spindle-sleeve-mt-4-5-mt-3/p97302912

You might investigate which machine in Grizzly's product line the bush fits and see if the equivalent model is available in the UK with Axminster or Warco or Chester paint on it.

If you consult this page, http://www.tools-n-gizmos.com/specs/Tapers.html you will see that 4 1/2 Morse has the same taper as 7 Morse, so that might be a source for a set-up gauge to make your own.

Boxford X10 series also use them:

me. if you let me have the measurements i might have one which was bought in error for my harrison m250.

Also used in the L5A lathe, and I haven't used mine since I bought it in 1987.

Didn't know it was called mt4.5 or that a 5C collet would fit, must lead a sheltered life!

Thanks for the offer - I will let you know the measurements later.

A 5C collet has the same dimensions - am I reading that right ?

Not quite.

A 5C collet is too big to fit within the outline of a 4 Morse taper.

A 5C collet fits within the outline of a 5 Morse taper. However, 5 Morse sets a lower limit on what the spindle bore can be, and thus the spindle bearings and also the spindle nose (chuck fitment) that can be put on the lathe.

All these things, especially the chuck fitment, add to the cost of the machine. The necessity for bigger chucks to fit the bigger spindle nose can limit the maximum rpm at which the lathe can spin.

4 1/2 Morse was used by the manufacturers as it is the smallest Morse taper within whose outline the 5C collet will fit.

On your Harrison 140, if it had a spindle with a 5 Morse taper in it, I suspect it would need the next size up L- nose on it. Similarly, on the Colchester variant, the 4 1/2 Morse allows a D1-3 nose, rather than D1-4.

Like a fool - I thought that would be an easy thing to do - as I don't have anything to measure I can't send you the measurements .... Doh....

From the chart the 4.5 MT is 1.5" on the gauge line - down to 1.266" - over a length of 4 1/2 inches - 0.6240 taper per foot. Hope that helps and PM me with the details - if you want to part with it.

Have had positive result from a generous member - but, it might not be what I need - we are going to investigate if it solves my problem.

If not - and as its such a thing that loads have lying around and don't often use - is there any one else out there that would want to part with a MT4.5 taper insert....

Do you need one or just want one?

Tony

I need one for my Harrison M250, I have created a "Wanted" Ad but it hasn't appeared yet. I don't know if I have created the ad correctly, it is the first time I have used this service.

I need one because i want one ! - In my eyes that's the same thing..... I'm sad like that..... its like having a Porsche 911 turbo and not having a whale bone fin.....

That's OK you can never have too many tools or too much tooling.

Tony

If Ketan were to have a batch made, I would certainly buy one for my Boxford 330!

David

4.5MT is also used on Boxford VSL headstock. Boxfords produced an adapted sleeve for 5C collets as well as a reducing sleeve but these are now out of stock and apparently not being remanugactured.

I have a 5C adapter but would buy a 3MT reducing sleeve if they were hardened and ground and available for under £30.

I believe there are a number of VSL owners who would want one too as this issue has cropped up in the Boxford User Group in the past.

on the VSL the 5C adapter is a bit more complex but that is off topic so let's not get drawn into that here.

Edited By John Paton 1 on 29/08/2021 22:15:54

There's lots of talk about getting someone else to do the running around to have these remanufactured and then the first indication of price above is a mere £30.

A healthy dose of reality is needed.

What size should the batch be? Let us guess at 100.

So, if sold at the price suggested, that nets £3000. Let us say 100% profit for the seller: £1500.

How long will it take for the stock to be exhausted? There will be an initial rush to buy them when finished. Let us guess at 50% sold within a month. Then how long for the rest? They will be hanging about for a year or more. And then once they are sold, the producer will have to deal with two or three enquiries for one for the next ten years.

How does the manufacturing take place? Where is the sample to come from and at what cost? Who has the measuring tools and skill to drive them to reverse engineer it? And to convert those measurements into an engineering drawing? What cost for the reverse engineering and drawing?

All this and more for just £1500 a year?

Anyone who wants one can make one. Buy a 3MT test bar (parallel round bar joined to a male 3MT) and set it up in a four jaw so the taper runs true. Buy a 5MT to 3MT open-ended reducing sleeve. Buy a couple of PCD inserts, set your compound to the correct angle and have at it. The hardest part of the process is feeding the compound smoothly enough by hand.

Thanks for the detailed synopsis - but not sure where the £30 price tag came from - nearest ive found are in the USA and he wants $120 each - and they are made to order rather than mass production which we all know for the community we inhabit is too small to sustain over manufacture of rarely used items

I have no problem making one - but wanted to know if anyone had a spare or unused item they wanted to sell before I went down the manufacturing route...