WARCO spindle bore

[Rik ShawParticipant @rikshaw]

[Rik ShawParticipant @rikshaw]

I used to own a WARCO WM-250 v-f lathe (the older non-inverter version) which I moved on some time ago. I was just going through some bits I had made for it and noticed that my shop made spindle stop for it is 28mm diameter. Out of curiosity I googled aforementioned spindle bore dia. but everything that came up for all variations of the WM-250 that I could find returned 26mm – without exception!

I had used the stop many times so I know I am not dreaming.

Any ideas?

Rik

[SillyOldDufferModerator @sillyoldduffer]

Is it because the spindle is tapered inside, and 26mm is the maximum that will pass clean through the hole?

[BazyleParticipant @bazyle]

There have been some comments over the years about far eastern machines and their spindle bores not being quite up to the spec dia. It is probable that in the past they used whatever drill was sharpish and so there was some variation between machines. So to avoid being caught out by people expecting it to actually do what it said on the tin the importers dropped to the lowest value in the range they were getting. It also means that those who really need the larger bore (eg gun nuts in the 'states) were pushed into getting the next more expensive lathe in the range.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Rik, all the Warco catalogues that I have puts it as being 26mm, however in the scan of the earliest one that have, has a little green balloon to the right of the little green van, which may explain things.

Bazyle could be on the right track.

Regards Nick.

Edited By Nicholas Farr on 23/02/2019 10:27:28

[JasonBModerator @jasonb]

Narrowest part of the MT4 taper on my 280 seems to be 28mm and then a slightly larger dia for about 50mm long and then a touch under 28mm with a machined surface not ground like the taper through the rest. Mine was one of the first 280 machines and they have always been sold as 26mm bore.

Which seems to be the opposite of Bazyle's comment as they are over spec

 

 

Edited By JasonB on 23/02/2019 10:34:26

[not done it yetParticipant @notdoneityet]

It will be a short taper if it would clear 28mm, I would have thought.

31.2mm down to 25.9mm is quoted for MT4, so the taper could only be about 60% of the full length of a proper, full sized morse taper

[JasonBModerator @jasonb]

Posted by not done it yet on 23/02/2019 11:26:26:

31.2mm down to 25.9mm is quoted for MT4, so the taper could only be about 60% of the full length of a proper, full sized morse taper

Same as the headstock tapers on most "proper" machines such as Harrisons, Colchesters etc.

[not done it yetParticipant @notdoneityet]

Surprisngly(?) my machine has a 4 MT in the spindle. I’ve actually no idea how long the taper is, but I know the spindle will pass slightly over 25.4mm. Perhaps it has a full length taper.

[SillyOldDufferModerator @sillyoldduffer]

Looking at the MT4 specification, the taper should drop from a diameter of 1.231" at entry down to 1.02" at a depth of 3.625"

1.02" is 25.908mm, or 26mm / 1" in round numbers.

So Rik's lathe will take a standard MT4 taper, and the spindle should be about 26mm at its narrowest. I think it's right. Nothing to do with conning barrel turners or the factory using random drills!

Dave

[JasonBModerator @jasonb]

I suspect rik's will pass more. As I said the 280 is also sold as 26mm bore and the bore gauge up it earlier today shows 28mm at the narrowest part of the taper as I reported above.

This is almost a full length of 1.063" silver steel that goes in without a problem, could not quite get 1.125" in.

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