Adjusting a Warco WM18 mill spindle
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- Опубликовано: 28 авг 2020
- Instructions for removing and reinstalling a Warco WM18 mill quill and spindle. Also a saga about why I needed to do this.
The video by Robin Renzetti is here: • TIPS ON PRECISION SPIN... 
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This is like one of those ‘soap opera’ cliff hanger endings designed to make you return to watch the next episode.
“Will the runout be greater? Has the bearing been damaged by over enthusiastic use of the wooden mallet? Will the original spindle need to be purchased and refitted? Could the mill morph into a Range Rover?
Will extra sugar in his tea be enough or will a second cup be required to figure it out?
See the next exciting episode to discover what happens next. 🧐
Yes, I do come across as somewhat in need of sustenance!
Enjoyable “fiddling”. 👏👏👍😀
If you think of vehicles wheel bearings which are similar to the bearings you are working on then they are designed to run hot.
Define hot.
@@thosoz3431 They do run hot due to the churning of the grease in the bearings. There is also more grease displacement churning with taper rollers than with ball element bearings.
By hot but not too hot I would say when they run so hot that the metal starts to change colour they are running in the TOO HOT range.
Do bear in mind this is why the grease specified for these types of bearing applications is designated as 'High Temperature' grease.
The mill looks basically the same model as a Precision Matthew's PM30-MV. Full manual available at their web site.
The top bearing mounting diameter should be a j class ISO fit. The bearing should be able move on the shaft without being loose. Also the bearings should be a better class than the ones used. The bottom bearing should have an m6 fit in all likely hood. To really set these correctly you really need a spacer between the inner races that sets the preload to exactly what it should be. Plus if the spindle gets hot the spindle gets longer reducing the preload on the bearings. Bearings can run 130°F with no problem.
Excessive amounts of grease will actually cause a spindle to run too hot. The bearing effectively becomes a pump trying to move the grease. Also a better grease to use would be something like Klüber NBU-15.
Thanks. I have the Grizzly G0704 manual which matches my mill design, but the PM one is more colourful and detailed.
Thank you for showing this video.
I think that I may be doing the same with my WM14 but I think I will invest in a hydrolic press first and some better double angled bearings.
I've wanted a hydraulic press for ages. The problem with this spindle, however, is that you cannot get it out without pressing downwards on the top of the spindle, that force being taken across the top roller bearing, which is improper. There is no chance of getting a bearing puller beneath the top bearing, as one normally would. But it isn't a tight press fit, so I assume the forces involved are tolerated by the bearing. You're thinking of using angular contact bearings rather than tapered ones? I did look for SKF tapered bearings but they seemed to be just the same as what I've got. Another problem you'll find with changing the bearings is that there is no provision for pressing the bearing shells out. I don't know, because I haven't tried it, if you could get them out by heating the spindle in an oven to, say, 150 deg C, and then freezing the shells by spraying them. Frank Hoose here ruclips.net/video/N7o4mPa9SGg/видео.html fabricated a special tool to get a grip on the bearing shell.
I was toying with getting a small Clarke press, but after watching your disassembly video, I am more inclined to buy the Clarke CSA12F 12 tonne press from Machine Mart. This way I would be able to move the mill inside the press frame, plus the press comes with base plates that would enable the removal of the bearings.
I have also been looking on Gears and Sprockets website for sealed bearings, as open cased bearings need a good supply of grease or copper slick, which I prefer to use.
I enjoyed your presentation Samuel. I have been in engineering/Training all my life (Gas & Steam Turbines) and have some understanding of your concerns. I have a new WM 14 and suffered a lock of the taper arbour, it hadn't spun just 'wrung' onto the taper making the quick release drawbar useless. I made a spacer to support the quill against the machine table (protected) removed the drawbar and using a suitably sized bar which sat on the top of the taper arbour resorted to a 3lb lump hammer ...it was still stuck fast. I spoke with Warco and we agreed to use the drawbar fully engaged with the threads (no cap Nut) and again a mighty blow with the 3 lb lump hammer it came free. My concerns were for the bearings that is why I found your video so useful. I am hoping that as the quill was locked to the table they we undamaged? Warco were very helpful and sent me FOC a new draw bar and cap nut. My problem was not unknown to Warco and several internet contributors. I hope I am not teaching my grandma so forgive me, but in metrology you wring slip gauges together dry and they sort of weld themselves together that is the drive/friction principle of the Warco arbour, the drawbar should only be 'nipped' when tightening. The important point is not to apply any lubricant to the taper arbour and spindle they should be cleaned and degreased before fitting. Do not leave the arbour in the quill for extended periods. Warco say they have had problems with new machines which have been pre greased in the factory and you can experience 'hydraulicing' preventing the taper breaking free. I was not sure from your presentation whether the shaft was stepped keeping the bearing inners at a set distance the pre load then being applied via the bearing outer races via the nut but if so it would have been more evident on the shaft and to do this would require precise machining. So I am mystified as you were as to the pre load arrangements. Once again many thanks and often someone, as you modestly say, is not expert in machine tool technology does not take things for granted therefore your questioning of the basics made things abundantly clear. I think these machines are far from perfect and do have design issues however they do work and are affordable. A comment was made re your lathe which looks to be an excellent budget machine. I have a Myford ML7 built in 1960 and it is indeed the Rolls-Royce of machine tools however refurbed Myford Super 7 (I don't think you can buy new) is about 7.5K
I am not sure about this locking you refer to. It is quite normal with my mill that whatever arbour is in the spindle remains there after the draw bar has been loosened. I just undo the draw bar by only a couple of turns and then bash it moderately downwards with the spanner to free the arbour (I don't need to use a lump hammer). Whether this is normal for mills I wouldn't know, but it seems reasonable. For example, the taper on my lathe tailstock also holds arbours in, and they did too on my old drill press. In all cases some force needs to be applied somehow to unlock the tapered arbour. Whether or not the quill is locked will not affect any loading on the spindle bearings: the bearings hold the spindle in the quill, the lock holds the quill in the column.
The lower spindle bearing is pressed onto the spindle, fixing the position of its inner race. The upper bearing's inner race is also a light press fit - that was what surprised me and made me wonder how one was supposed to adjust the preload. Both outer bearing seats are fixed in the quill, and preload is established by screwing down the upper bearing's inner race on the spindle. There is a second part to my video which may make things clearer (I can't remember!).
Your Myford will be much better than my Chinese minilathe.
@@samuelfielder It was indeed an 'abnormal' situation and discussed in detail with WARCO if you search Google several people have had 'taper lock' a hydraulic press, should the quill be removed, would in this case cause distortion, the impact method providing the main spindle is locked against the table was the best solution, again as approved by Warco. I am still confused as to the bearing preload this is because we do not seem to have precise instructions as to the assembly philosophy. I hope my experience helps others as your presentation did for me. Interestingly Warco said they have had problems with new machines due to oil or preservative being applied to the taper arbour on assembly the secret seems to be to fit dry and the jacking release method will work. I certainty was not comparing your lathe to a Myford as the machine it looks a very good tool for the money.
Nearly identical to my Amat25LV to remove the spindle.
That top nut holds the draw bar captive on mine, MT3 spindle.
I had a similar problem, I had to tighten the preload, due to runout.
It's also belt driven, no gear noise.
I've never run over 1000 rpm, for milling as a general rule.
Adam
On mine the draw bar just goes through that top nut and is not captive. I was using the feeds and speeds calculator from Littlemachineshop.com, which said 1940 rpm for a 10mm dia HSS end mill in aluminium. Wrong? Also, Adam, do you know if the inner race of the top spindle bearing on your mill is a slip or interference fit?
@@samuelfielder
The top bearing is an interference fit on mine.(same Chinese factory :) )
As for spindle speeds, I was taught to start slowly, checking the finish and the sound of the cut.
Pointless, over heating the cutter, I'm in no rush, no dead line to meet :)
Adam
Yeah right those springs are nasty to fiddle with. I'd suggest a large C clamp or two in future endeavors. It'll be a touch easier than trying to mash it down with a wrench.
I have a smaller warco mill. I think I may have stripped the fast gear. Any idea how I go about disassemble the head to look in the gearbox. Thanks
Not really. On mine, one can remove the fine spindle feed knob, and the quill DRO, and then remove the shiny front plate from the head. This offers a view of the gears.
@@samuelfielder thanks. Unfortunately there's nothing behind my plate. I think there's a problem with the h/l gearing
@@justa1098 Warco did tell me that the WM18 and WM16 are made by completely different Chinese firms, so my experience doesn't transfer.