Help with odd milling machine spindle taper

I recently purchased an Adcock & Shipley horizontal milling machine, model 1AD, built in 1949, in Leicester. It has made it all the way to Australia, and despite its age, it is still going strong and I am very happy to have it. My question: the spindle taper looks very much like an American National Standard, but it is too big for an NT30 and too small for a NT40. I measured the taper at 3.5" per foot, which is consistent with the NT series. The small end of the tapered section is 20mm dia, the large end is 35mm, over a distance of 50mm. I have heard that there was a brief period where an NT35 was part of the standards. Could this be a rare example of the 35 before it was discontinued? This is a fine machine and I am lucky enough to have arbors for 7/8, 1 and 1 1/4 inch milling cutters. I've been unsuccessful in finding any other tooling to fit the spindle taper - it looks like I will have to make arbors for my metric bore tooling. Any help or suggestions greatly appreciated. Thanks, Tony

This may help a little, Tony: **LINK**

https://www.cnczone.com/forums/uncategorised-metalworking-machines/71862-nt35-taper-bt35.html

MichaelG.

**LINK** ?

Thanks. Expensive stuff.....BT35 and NT35 seem to exist, but not common. I will have to turn up what I need. Another project on the 'to do' list....or I'll just resort to the Chinese vertical mill for when I use the metric bore tooling (and in particular the involute gear cutters).

Still not 100% sure if that is what A&S built into this mill. I thought perhaps someone in the UK might have some experience with these vintage mills and be able to confirm.

You might be able to turn down a 40. I have a 30 taper that didn't seem to fit and wondered if it was a 25. Then I noticed it had been broken at the eject slot and brazed together again, then turned down but that made it too small.

Tony, where in Oz are you? They are commonly used in larger hi speed routers I see in Melb

You want BT or NT? ER32?

I'm in Melbourne. The taper on the machine is definitely of the NT (or NMTB if you prefer) form. I gather that a BT taper can fit an NT spindle, with some changes to the draw bar (not a big deal). I was after some positive confirmation from someone who had one of these machines, that the spindle is indeed NT35. I have looked high and low, but have not found any standards listing the dimensions for a NT35 (yes, I can find details for the BT35).

Ideally, I need an arbor for the machine that will take 22mm metric bore milling cutters. I doubt one exists on the planet, so I'll make one. In addition, if I can find a taper shank that will hold an ER collet (say, ER32), I'd be happy to have one; I suspect this will have to be a modified BT35 from the CNC world. (supply/demand seems to put the price of a BT35 much higher than the more common 30's and 40's).

Tony,

I've not heard of an NT35 taper before - but I do have a Victoria H0 mill with an 1_3/8th N.S. taper - which was (I believe) a wartime standard. It also sits in between the NT30 and NT40 taper sizes. The dimensions you are giving don't seem to match this taper but I thought I'd mention it's existence as I've found it very hard to get information on this taper and it is not well known.

Just a thought...

Regards,

IanT

Tony, Have sent you a PM

Finally worked out how to include photos with the post. So, this is the taper on the arbor. I've also included a sketch of the dimensions - these are 'as measured' so will be near but not exact, for example, the angle is most likely to be 16.59, indicating that it is a standard 3.5" in 12" taper.

Interesting to hear about the 1 3/8 taper. Wartime standard, could have easily found its way into a machine in 1949 I suppose.

Tony,

I have a .png drawing of the NS taper (which also includes the 30/40/50 tapers) and gives their relative dimensions. The 'G' measurement - the top end of the taper, for the NS taper is 1.375" which is 34.9mm - so this seems to suggest this taper.

I cannot post .png images here but if you pm me - I will email you the image.

Regards,

IanT

Hi Tony, I know the post is quite old now but you may still be checking...….

I also have an Adcock & Shipley 1AD and it is similarly equipped with the mystery taper that you refer to. I believe it is known as '1 3/8" N.S.' (N.S. for 'Non Stick' and is described in British Standard BS 739: 1937 as '2 5/16" Nominal'. It is also described here:

http://www.oldengine.org/members/diesel/Tables/Clarkson1.htm

I have searched for more than twenty years for tooling and turned up precisely nothing.

I think you have two options:

1) I have turned up an adapter to convert the taper down to 30 INT. I can then mount a 30 INT Autolock chuck. It's relatively easy to do although it may compromise the accuracy a little. The taper is the same gradient (7 in 24) in the two sizes.

2) There is a modern CNC fitting, BT35 that is close, a bit bigger but should fit. Again it's 7 in 24 gradient but due to the increased size,it may need a drive adapter to engage the drive pegs. There are many fittings available from Lyndex-Nikken in the States:

https://www.lyndexnikken.com/BT35-Morse-Taper-MT1-Holder-p364.htm

I'm hoping to be able to use a BT35 to 3MT adapter and then use standard MT tooling.

Stick with the 1AD! They're solid, well made and accurate and have survived the years well.

.

Ian

if you eMail the .png to me, I can easily convert it to .jpg and post it here

I will send you a PM with my address

MichaelG.

Can somebody [perhaps a moderator] please help me here ?

I clicked on ‘Message member’ and sent a note to IanT

... but received the following reply:

[quote]

[/quote]

Surely we can’t have two members with the same account !!

MichaelG.

All sorted now ... Panic over

MichaelG.

Tim, thanks so much for keeping on the case! I agree, the 1AD is a great machine and beats a good many Asian machines I have used. I like your suggestions; the adaptor to take a 30 INT is certainly worth a try; I've noted the BT35 being available (often found on CNC machines), but was unsure if I could get them to fit, so I haven't invested in one to play with. A third alternative is to cut an arbor from a blank of steel....bit of a job, but if you want a full length arbor (and I'd like one to take my 22mm ID gear cutters; they just don't fit on my 7/8 arbor) you may have no choice. I have found a lump of 4140 60mm dia the right length....on the 'to do' list. I'll post up some pictures when I get it done. Cheers, Tony

Tony,

As mentioned, I have an 'NS' arbor for my Victoria - so I don't have quite the same problem - plus I tend to keep the vertical head on (as it's somewhat heavy). However, I also have a smaller horizontal (Atlas MF) that I sometimes use to drill & mill direct (horizontally) from it's arbor socket - as all my MT2 stuff fits it (ER32 etc).

I haven't really needed to do this on the Victoria yet but for some set-ups it is a useful thing to be able to do - and the Victoria has a larger table/better travel etc. So I have thought about adaptors but decided that the best route would be simply to turn a direct fitting NS taper (probably on a mandrel between centres) and then machine (bore) it in-situ on the mill - e.g. use the mill as a lathe (would need a top-slide fitting - yet another job!)

But if I needed a new arbor, I think I would look at making it from two pieces (taper body + arbor) loctited/pinned together and turn the whole lot between centres - the arbor doesn't need to be full length if your lathe can't handle it - it's often better to mount cutters near as possible to the mandrel nose anyway...

Just a thought...

Regards,

IanT

Ian, thanks for the excellent suggestion to build the arbor in two pieces. It would generate a lot of swarf to make it out of one long lump of material. You are correct on your other point too, it does not have to be full length for the application I have in mind.

I grizzle about the rare spindle taper, but the machine came with 3 arbors (7/8", 1" and 1 1/4", so I really shouldn't complain. I'd like a 22mm dia arbor to fit my gear cutters (of which I have a fair number), and then a little further down the priority list would be an arbor to fit some collets etc. In truth, I can get around all of this on the vertical mill....but you know what it's like...the challenge of making tools to extend the use and range of the machines is strong.

It has been an interesting discussion about these fine old machines and their wartime tapers.

Thank again for your input. Cheers, Tony

I have an old "circa wartime" Herbert 10 vertical with this 1-3/8 taper, fortunately it came with a Clarkson autolock. As Tim suggested I also have turned up a "thin" adaptor sleeve to modify it to Int 30, good solution to my mind.

Great quality the Herbert, unfortunately a mate left the coolant pump motor running, there was not slosh in the cast base, motor burnt out ! Another project.!