Blank end Arbors

This topic has 14 replies, 8 voices, and was last updated 11 October 2025 at 05:28 by jimmy b.

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1 October 2025 at 00:54 #818096
Vic
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@vic
Are blank end Arbors soft all the way through? Just wondering if I can bore a hole all the way through an MT2 arbor. Or can you buy one with a 10mm hole through the middle?
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1 October 2025 at 07:22 #818116
jimmy b
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@jimmyb
I believe they are fully soft, at least every one I have ever bought has been!

Some time ago, when things were a bit quiet at work, I knocked out a box full whilst no one was around. should last me out!

Jimb
1 October 2025 at 07:27 #818118
DC31k
Participant
@dc31k
You could test it yourself.

If the arbor is hard, all you have wasted is the time it takes to re-sharpen a drill bit.

It may not be relevant, but 10mm through a MT2 might obliterate any drawbar thread at the small end.
1 October 2025 at 18:30 #818200
Vic
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@vic
On 1 October 2025 at 07:27 DC31k Said:

You could test it yourself.

If the arbor is hard, all you have wasted is the time it takes to re-sharpen a drill bit.

It may not be relevant, but 10mm through a MT2 might obliterate any drawbar thread at the small end.

If it’s too hard to drill, I’ve lost the cost of buying it! I don’t need a draw bar.
1 October 2025 at 20:34 #818221
Vic
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@vic
Not as cheap as they used to be, but I’ve ordered one from RDG Tools.
2 October 2025 at 07:41 #818258
David George 1
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@davidgeorge1
HI Vic Let us know how you get on. I have machined the end section making one to a chuck arbour and another into a boring head but neverthought of drilling through the taper part. Whilst at work we would make some parts which were part finnished then carburised then we would machine of the carburising of some areas to remove the carburising then it was sent for hardening as only the carburised areas would harden. These were ground on the hardened areas and the soft areas were drilled tapped milled etc to finnished item.

David
6 October 2025 at 18:04 #819075
old mart
Participant
@oldmart
I have never tried to drill right through a MT arbor. However, I have cut off the tangs from a couple of drill chuck Morse Taper arbors and drilled a hole about 1/5 of the taper length without any bother to allow greater stroke of the tailstock in my 7 X12 mini lathe, which also increases the available bed length. The hole accepts the end of the tailstock leadscrew which is self extracting. It is common for soft end MT arbors to have a drawbar end rather than a tang, so I recon it would be possible to drill right through.

Your 10mm hole would only leave 2.25mm wall thickness at the small end of the MY2.
9 October 2025 at 20:01 #819583
Vic
Participant
@vic
On 2 October 2025 at 07:41 David George 1 Said:

HI Vic Let us know how you get on. I have machined the end section making one to a chuck arbour and another into a boring head but neverthought of drilling through the taper part. Whilst at work we would make some parts which were part finnished then carburised then we would machine of the carburising of some areas to remove the carburising then it was sent for hardening as only the carburised areas would harden. These were ground on the hardened areas and the soft areas were drilled tapped milled etc to finnished item.

David

The one I got from RDG is soft on the end and through the middle so drilling a hole through the middle was no problem. 😉
9 October 2025 at 20:28 #819588
Martin Kyte
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@martinkyte99762
Does no one machine their own these days. I know it’s easier if you possess a taper turning attachment but one you are set up you can make a batch to last you years.
10 October 2025 at 16:07 #819715
Vic
Participant
@vic
I’m just waiting for the collets to arrive now and I can try it out.
10 October 2025 at 20:40 #819770
old mart
Participant
@oldmart
We have a taper turning attachment on the Smart & Brown model A and I decided to produce a MT2 taper. What you need to appreciate is that a Morse taper requires accuracy within a few seconds of arc. I set up the angle using a true running male MT2 in the spindle and a DTI set exactly on the centreline. The tool height has to be exactly on the centreline also. The setup would only work for MT2 as for some unknown reason every Morse taper is a different angle. The MT2 produced was unused for years until I wanted a cutter to go in the pillar drill which has backgear to cut various diameters of Tufnol used to make cable pulleys for the flying banana.

Vic, I see a tang on your arbor but no 10mm hole. Is the tool a small rotary broach?
10 October 2025 at 21:34 #819778
Chris Kaminski
Participant
@chriskaminski64716
On 10 October 2025 at 20:40 old mart Said:

. Is the tool a small rotary broach?

see: https://www.model-engineer.co.uk/forums/topic/taping-small-holes/page/2/#post-818365
10 October 2025 at 23:52 #819785
Vic
Participant
@vic
It will possibly serve two purposes. The primary purpose for me is as a sensitive drill. In addition it could be used as a small rotating centre with interchangeable centres.

Inspiration was from here:

https://youtu.be/L0ZTw5J8oTE?si=6ng5kst7cnbtFlDM
11 October 2025 at 00:56 #819786
howardb
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@howardb
On 9 October 2025 at 20:28 Martin Kyte Said:

Does no one machine their own these days. I know it’s easier if you possess a taper turning attachment but one you are set up you can make a batch to last you years.

On 9 October 2025 at 20:28 Martin Kyte Said:

Does no one machine their own these days. I know it’s easier if you possess a taper turning attachment but one you are set up you can make a batch to last you years.

The advantage of m/cing your own blank end arbors from bought in stock is marginal, considering the cost of the material.

Of course it’s ok if you have the material in stock or enough in the scrap and odd ends bin.
11 October 2025 at 05:28 #819791
jimmy b
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@jimmyb
On 9 October 2025 at 20:28 Martin Kyte Said:

Does no one machine their own these days. I know it’s easier if you possess a taper turning attachment but one you are set up you can make a batch to last you years.

I did, but having a “spare” CNC machine made it very, very easy!!

I also ran off a lifetimes worth of slave live centres that day…….

Jimb
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