Beavermill Runout

Hi all,

I got an issue…!!!!

Following my past posts on what I believed was a bad arbour, the cause now looks to be runout of my Beavermill. I have had a dial indicator on the inside of the taper spindle ad got 0.11mm runout at about a rotational speed of 100rpm.

You possibly can tell I am very new to this and only just got this mill. I am not bad in following technical guidance and do work on small machinery and old Land Rovers but never touch a mill before.

Sorry but not totally sure on the model of Beavermill I have, but is exactly the same as the drawing below.

So…… the big money question to you guys. How can I get rid of this runout and is there any “how to” guides or technical documentations on how to do this? I don’t mine getting my hands oily but prefer in having guidance on how to do this then just diving in blind and hoping I can put it back together (and finding the issue).

Yes that is 'country mile' in terms of spindle runout.

Put a tool in the spindle taper, set the dial gauge against the outside and use your hand to pull the spindle about, see if the effort you put in is reflected in the dial gauge reading. Repeat by heaving on the top of the spindle, it might simply be that the top support bearing is bad.

Edited By JasonB on 20/09/2023 08:44:43

To add to Pete's post:- Set the speed to the highest possible (it is a variable speed Mk2 VBRP, not the step-pulley version isn't it?). This will make the spindle easier to turn by hand. If it's still too much (shouldn't be) then it is acceptable to use an adjustable spanner on the driving dogs at the bottom of the taper. Shouldn't need that though.

Also check whether you can move the spindle from side to side with firm hand pressure. Best to do that with the arbor in, to give you something to grab hold of. If you can get the mag base to stick to the side of the quill and indicate any movement of the spindle from there, that would be a definitive maker for loose (not necessarily buggered) bearings.

Best to keep the questions, answers and comments in this thread, that way people can see all of the detail in one place. There is another thread "all things beaver mill" on the forum. That might be good for a read through if you haven't found it yet. It's got a fair collection of problems, solutions and wisdom on all things Beaver in it. There are a slack handful of other Beaver related threads that the forum search will find as well, for background reading.

Edited By Mark Rand on 19/09/2023 21:17:57

Edited By JasonB on 20/09/2023 08:45:24

Hi Antony,

0.11mm runout is a lot more than what I get on my cheap Chinese milling machine. Is the runout the same if you remove the drive belt and rotate he spindle by hand? With the indicator on the taper, how much can you push the spindle sideways with your hand, up or down? This would tell you if there is much play in the spindle, if there is little movement - far less than the runout - you may have a problem with the spindle itself. Is there someone knowledgeable that live near you and cn give you advice? Good luck.

Thor

This is the biggest Beaver thread in here All things Beaver Mill | Model Engineer (model-engineer.co.uk) there are several others as well

I do not measure runout under power. I turn by hand. Have you checked turning by hand?

Is the arm that i holding your indicator sufficiently stiff?

Oops, I meant your other thread :-

Play in new arbour for mill

But ignore that, since Jason has moved the conversation to this one.

Edited By Mark Rand on 20/09/2023 09:32:42

Hi Guys,

Thanks for the comments, yep its a variable head and i have noted movement on the spindle when holding it at the bottom going side to side. Could my first investigation be to see if any holding down nuts to the spindle are lose? Any direction on how to go about this, plus does anyone know the torque settings for this head? Or to purchase the documents that have these in.

There are two likely situations, assuming the run out is real and not due to a misunderstanding. Either there is slack in the bearing setup, or less likely, the spindle has been bent in some previous serious crash.

To test for bearing slack, fit an indicator which bears on the end of the spindle (ie vertically), and try by hand to see if there is vertical play, that is try to lift the spindle. Any vertical movement by hand should be less than perhaps 0.005mm. In the event that adjustment is required, look for the makers recommended procedure, and proceed with extreme care.

Testing for a bent spindle is less easy, and would probably need the spindle removed then the bearing inners removed (assuming ball or roller races), and supported and rotated on V blocks on the bearing fitting diameters. It would be best to involve someone with appropriate machine tool experience.

Hi Malcolm,

Thanks for the comments, will have a look in to vertically play over the weekend and report back.

Tony at lathes.co.uk has (for a slightly eyewatering price, but he has to make a living) a set of documents, that include assorted user manuals, maintenance instructions and sales brochures.

In the meantime if you head to to the server in my workshop, you can find:-
VBRP Mk2 manual.pdf

On pages 24 and 25 you can see parts 52 and 53, which are the nut and lock nut that control the spindle's angular contact bearing clearance/pre-load.

Page 39 gives instructions to remove the quill to get at these nuts.

Note:- if the mill makes a 'roaring' sound that gets worse with invreasing speed, it tends to indicate that the spindle bearings are shot. It's possible to puzzle out how to ged the spindle out of the quill and inspect the bearings from the diagrams. Hopefully, the nut and locknut have just vibrated loose

Edited By Mark Rand on 21/09/2023 23:45:35

Thanks Mark,

For some reason I couldn’t navigate the that section on the server to find them manuals but have asked “Tony” if the packs he provides include details on torques setting or pre-load measurements needed for rebuilding the machine. Will keep my fingers crossed..!!!

Shame there are no YouTube videos on people doing this… would have been a great help.

Hi Malcom,

I measured the vertical play in the spindle, and I got 0.010, which if 0.005 would be roughly ok I am 50% over that. I am possibly going to take Mark’s direction and see if the top nut and locking nut are lose on the spindle. But the shocking runout is the 0.11 on the inside of the spindle. Any ideas what can course this? I can only imagine play in the bearings allowing this movement?

Edited By Antony Harding on 22/09/2023 20:07:47

That would seem the kind of value to expect on a well used machine, and normally slight adjustment of the bearings would reduce it. Unfortunately, in conjuction with the runout, it suggests either a problem with one of the bearings, or the spindle has been crashed into something solid and bent. I am afraid I know nothing of the Beaver Mill, so I can only make general comments.

Unless anyone has an alternative suggestion, it looks like the spindle needs to be removed. I think it was suggested the quill can be detached, and this would allow a better inspection. With it on the bench, a quick test would be that the splined drive shaft is closely concentric when rotated. If it is not, it either points to a bend lower down, or to a partial failure of the upper bearing which can be due to breakup of the cage holding the rollers or balls so that they clump together rather than being evenly spaced. Such failure of the lower bearing would presumably lead to more eccentricity than you have measured.

Good luck with investigating this, and keep us informed. This sort of problem often turns out to be something entirely different from preconceptions, so do look out for the unexpected.

Make adjustments to elimnate the vertical spindle movement and you'll probably find that the radial runout also disappears. Start by adjusting it down to a thou or so and then check the radial.

Don't measure runout under power. Any resonance will exaggerate the measurement.

probalbly the spaces in the file name.If the browser is forced to use Gurgle to search perfectly honest URLs you've entered, then it treats them as a search expression rather than a address.

Fixed the URL to **LINK**

There should be no vertical play at all. Once you've got the quill out. Adjust the nuts until there is slightly more resistance to rotation than in the 'floppy' state and you should be good to go. Take the opportunity to grease the bearings at the same time. Not sure about the Mk2, but on the Mk1 there's a grease port on the side of the quill that takes a hemispherical/conical grease gun tip like the ones on this page

As noted before, if the mill now makes a roaring/hissing noise in the higher speeds, that's an indication that the bearings are beyond their best before dates.

Owning and maintaining a 1960's or earlier machine is an exercise in engineering that the youf of today rarely encounter. Good for the soul and part of "growing up and being British"

Edited By Mark Rand on 22/09/2023 23:40:47

A further thought, for the lower bearing next to the arbor, partial failure of the roller cage might allow one or two of the rollers to skew out of position, resulting in the observed small amount of eccentricity.

Regarding adjustment, agreed the optimum end float is zero. However, roller taper generates an end force on the rollers, and the ends run against a flange to keep them in position. This is why there is an observable increase in drag when the end float has been adjusted out. Unfortunately with a double nut, the correct end float set using the first nut is displaced when the second is locked against it. So you need to start with enough slack so get to the correct final position. Unless you are happy that you can distinguish this correct friction from the amount when too tight, the safe solution is to set almost negligible slack, commonly 0.0025mm or 0.005mm (0.0001” or 0.0002&rdquo.

Hi Mark / Malcom,

This advice is great and do appreciate your time in helping me. I will attempt to have a go at reviewing the spindle nuts to see if I can take out that play next week. And while in there review the bearings and grease them. After that will measure the run outs again and will report back.

Yep love the old machinery, but being new to them, and my first need a little guidance and assistance on the way… fingers crossed. !!!!