Warco WM18 milling head shake ( technically spindle is precessing) when plunge milling a blind slot.

[michael jones 16Participant @michaeljones16]

Hi all it's mjj here.

Thank you all for your comments. All very interesting and entertaining. Before making my initial post I had emailed Warco suggesting I take my machine to them for them to examine. I have now recieved a reply and they have accepted and with the possible offer of a replacement machine waiting. So here's thumbs up to Warco. I would be happy with just replacement parts if that.s all required. What's mutually fair is fine by me. If I can help prevent this problem happening to others all to the well and good full marks to Warco.

Now returning to as many comments as I can . Firstly taking note of one persons reply about checking if any was loose . Well before embarking on trying to find some sort of gib adjustment comprise I gave the machine a quick once eye scan. Whilst not loose I did find that the milling head has tilted by about 3 degrees. Also attempting to put it back i fond that the holding screw for head swivel detent was totally loose so that I was unable to retract the pin. It looks like vibration has made itself known. Prior to this problem occurring the head was at 0 degrees for certain. I haven't had any recent crashes of a cutter or ER32 collet chuck since I ditched using those huge clamps from one of those 52 piece clamp sets. Ditching them in favour of some home made clamps and a more than half decent machine vice. Now the direction of tilt was such that it would favour the long cutting edge of the slot drill so this will have some bearing on matters. Most likely making the hole larger and promoting more shake.

I would agree with many of the later comments. In many ways I've based my actions on past experience …..The only exposure to milling was in training and thus that on industrial machines. I had that I had made due allowance for the size and quality differences in the machines. I can't think that I have been trying to push things too hard by seeking to get high metal removal rates. However I would accuse myself of going perhaps too gently. Well at least I my Myford super7. My mind boggles at what some claim to achieve and struggle to get tipped to cut anywhere half decent … too reluctant to push it too hard I guess.

My original posting apart from the obvious was to get some kind of proper handle on what I should or not expect from hobby time machines I guess. Perhaps as one of you suggested the unlearning phase.

On a lighter note since someone mentioned Cinncinnati machines , back in the late 60's / early 70's the company had one of their numerical controlled drills installed, i think it must have been hydraulically controlled.

On commissioning day news spread through the company like a wild fire . While the commissioning engineers stood around watching the large paper tapes whirl into action as one pressed the go button. The machine sprung into life only make very load bang it tried to drill a large diameter hole from the bottom of an 18" by 2 foot cast iron casting! Ooops could well have been one of the first instances of the realization that there are different definitions of what sign should be used to describe axis movement.

Thanks again all for your comments.

mjj

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[gerry maddenParticipant @gerrymadden53711]

A while ago I reported on making stiffness/compliance measurements of the spindle in my mill. I measured about 3 microns/Kgf in the X axis and 0.9microns/Kgf in the Y axis on my Wabeco.

It's quite and easy thing to do. Just put a drill in the chuck, set a DI on to it, then pull the drill shank in the horizontal plane with a spring balance. Then divide the total deflection on a DI by the load that you apply.

In my case I found that I was able to improve my X-axis figures by about 30% by re-machining the mounting face of the head casting which sadly wasn't very flat.

Spindle stiffnesses are never quoted by m/c tool makers or sellers which is a pity. But if people on here were to do this kind of check it might help those looking to buy new machines, or even encourage manufactures to improve the breed.

Gerry

[Boiler BriParticipant @boilerbri]

Hi. Just caught up on this. I have this machine also. It has the same problem only when you plunge I have a bit of quill lock on to steady it. Putting the lock on moves the centre of the quill about 15 thou! I mentioned in another thread somewhere that the housing casting has a flaw in it like the casting was incorrect. It does not noticeably open or close when I tighten the quill so I think it's just a poor machined fit in all the parts. So long as I use the same setting I get accurate enough results for what I do. I ain't making watches. I did not notice the flaw for best part of 5 years.

We have to remember these are hobbyist machines made to a price and Warco will only have so much margin in them. Just to be clear I am not knocking Warco. I have had good technical back up when I most needed it.

Bri

[Boiler BriParticipant @boilerbri]

Don't want to start another thread.

Has anyone fitted the new power drive to their machine? I am thinking of buying one for my wm18.

I would like to know if there ok before parting with my beer credits.

I machined a 291mm length of aluminium today and my arms are dropping off with all the winding.

Brian

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