Super Lux Rigidity

[Dan CarterParticipant @dancarter89683]

Hi All,

This is mostly aimed at Raymond or anyone else with a Super Lux, Warco super major or other such variant, although as always, all views welcome.

Having had the thing for a couple of months now, have been a bit disappointed with the rigidity – chatter etc is definitely better than my old X2, but not that much given the size/weight difference.

Am now a bit suspicious of the head to column connection. I can move the tapered z-axis gib to the furthest extent of the adjustment screws without locking up the column – in fact even with the actual head locking levers fully tightened, the column moves vertically either with the handle or the head elevation motor. This surely cannot be right ?

Another data point, If I put a dial indicator on the table and indicate the bottom of the head casting at the side, I can move it 5-10 thou by pulling on the head, This seems like a lot to me, as is bound to also be happening during machining ?

Grateful for any thoughts.

Dan

[Dan CarterParticipant @dancarter89683]

[Neil WyattModerator @neilwyatt]

i would have expected the gibs to be able to lock the head against any forseeable load, but that doesn't necessarily mean totally locked solid.

5-10 thou sounds a lot, but a while ago someone reported similar movement in a lathe – as I recall the lever and weight they were using was imposing about 40 times the load a cut would have imposed. Assuming you can put a 50-pound pull on the top of the head, that may be vastly more leverage than that imposed by the cutting edge of a 12mm diameter cutter

You need to work out the actual cutting forces (based on the maximum torque at the tool) and apply a comparable load to get a meaningful comparison.

Neil

[Clive FosterParticipant @clivefoster55965]

I'd start by running a beady eye over the relative sizes of the gib adjustment screw head and the slot in the gib it engages with. The Chester Lux style machine (Lux style and size but not from Chesters usual supplier) I got a decade or more back had slots over 1/8" wider then the adjuster heads on a couple of the gibs. Mutual alignment between adjuster and gibs was poor too. Especially as the adjuster screws were bent to sort of take up part of the error. Symptoms were erratic and totally inconsistant backlash and play in the slides. Took ages to figure out what was wrong. Mostly because I never thought to look for something so fundamental, obviously incorrect and easy to see. Pig to fix too as I had to re-align the adjuster tapped holes.

If the adjuster to gib engagement is OK I'd slip a suitable strip of steel under the head side of the gib to take out most of the play and see how it goes with something approaching proper adjustment. Probably have to get creative with bent tabs on the ends to stop it sliding around. If that fixes it glue it to the gib. It will work well enough if the gib is straight and flat.

Neil

Any decently engineered taper gib system will lock things solid (for all practical purposes) if driven into hard engagement.  The taper is well in the self locking range.  Its as good a rough test as any for excessive wear on the gib.

 

Clive.

Edited By Clive Foster on 01/01/2017 20:49:34

[Michael ToppingParticipant @michaeltopping17870]

I have a Warco super Major and if I have the column clamps locked it will cause the power feed motor to stall? I don't get chatter at all with reasonable depth of cuts etc. I have adjusted the column jibstrips a couple of times over the 2.5 years I have had the machine and it is possible to totally lock the column if you are too enthusiastic. I Don't get any movement at all from the column it's rock solid.

I think you might have a problem with the gib strip being undersized. Bear in mind that the head on these is very heavy and if you have play the weight will tend to tilt the head forward.

Michael

[Dan CarterParticipant @dancarter89683]

Michael,

You get no movement at all pushing on the head ? That is useful to know.

The slot on the gib is bigger than the head of the screw, but does this matter given there is a screw at each end of the gib ? I don't think it can move once both screws are tight.

I suspect you and Clive are correct about the gib being too small. I will try Clive's suggestion tomorrow. On further reflection this is almost certainly true – when I tighten the head locking screws, it take almost a full turn. the table locks only need a quarter turn.

Neil, fair point about the cutting forces. I had a go with **LINK**

In the unlikely case I was doing it right, for a 2mm deep slot with a 12mm cutter it gives a tangential force of 298N, which was in the ball park of how hard I was pulling.

Dan

[BazyleParticipant @bazyle]

I don't know these mills in detail but it sounds like the taper gib has an adjusting screw and one end and a corresponding screw at the other end that is designed to take up the slack formed by the fact that the first screw is working in a loose slot. How is locking done? Is there a screw that pushes the gib from the side?
I would expect that if the locking screw is backed off, and the thin end adjusting screw is loosened, then the screw at the fat end of the gib should be able to tighten up and lock the head pretty firmly. At this point it should not be possible to move the head in any direction. If the gib angle is not right it will only contact over a short even point distance and provide poor locking and also movement in the X direction. Careful examination may show the contact area with or without using blue.

However if the gib is loosened a bit so there is 1 thou gap all along and a locking screw that is half way up pushed against the gib it will lock the head in the z direction but that 1 thou gap would allow the gib to bend and hence allow a small rotation along an axis in the Y direction through the middle of the head.

[Raymond AndersonParticipant @raymondanderson34407]

Hi Dan just saw your post. I have the Chester Lux The Gibs should never go it the full extent, so sounds to me like the Z axis one is to small [ narrow ] You should never be able to move the head if the gibs are adjusted correctly. I also had the slots "oversize " on all my gibs XYand Z made new screws from En 8 so they fit perfectly in their respective slots. It does make a big difference as the gibs cannot move in relation to the screw heads.

Because of the weight of the head it is possible to notice some deflection on the Column with a gauge. I still have some on mine, but very little and you need to push fairly hard.

Did you ever do what I did with the Devcon/ Hilti injection ? that really made a massive leap in the accuracy of each component in relation to each other, and had some effect on rigidity but mostly accuracy.

I have seen some columns that have been filled with epoxy / Granite dust It seemingly makes the column more rigid, and I can see why. I have not done that but may be tempted in the future as I have a thing about Rigidity, ie the more the better.

So you should look at making a new Z axis Gib [ and you can make the slot to fit the original screw, or make 3 new screws to fit their respective slots.

cheers.

[Dan CarterParticipant @dancarter89683]

Thanks all. Following Clive's suggestion I pulled it out and stuck a hacksaw blade (with teeth ground off) on the head side of the gib. it ended up fairly tight in the middle of the adjustment range so the gib must be undersize by about the size of the hacksaw blade (0.6mm)

Head deflection and more importantly chatter greatly improved.

Raymond, I haven't done the epoxy injection yet, but it is on the (long) to do list. As regards making a new Z-axis gib, It is a bit daunting given the taper in both directions – do you see any problem with using a steel shim on the back to fatten it ? Am also tempted to ask Chester what they are planning to do about it given that it is only 3 months old.

Dan

[Raymond AndersonParticipant @raymondanderson34407]

Hi Dan, yes I can understand your reservations re making a new gib. I am not sure about a shim on the gib strip It does seem a bit "agricultural " but then that is maybe just me. Since it is only 3 months old you would certainly be advised to contact Chester. There is no way, that the gib should go in as far as you mentioned.

When you get things sorted from Chester, the resin injection really transforms the accuracy of the machine.

It is a machine that is very capable once it is "sweetened up " My one gets quite a lot of use, more than me K & T but then again I have hardly needed the K & T [ yet ] 2 vastly different machines of course.

Contact Chester and tell them your woes re the gib, and don't take any flannel. the gib strip is wrong or the dovetail is wrong.

cheers

[Dan CarterParticipant @dancarter89683]

Chester have asked for photos (pretty reasonable), so now have to remove my hacksaw blade hack. Will post with the response.

As an aside, I have just noticed that locking the x-axis makes the y-axis harder to move (handwheel stiffens up) – I can't see how one would affect the other, any ideas ?

Dan

[Anonymous]

Posted by Dan Carter on 04/01/2017 18:46:08:

As an aside, I have just noticed that locking the x-axis makes the y-axis harder to move (handwheel stiffens up) – I can't see how one would affect the other, any ideas ?

Poor saddle/gib design; tightening the X-axis lock distorts the saddle, affecting the Y-axis ways.

Andrew

[Dan CarterParticipant @dancarter89683]

I said I would update:

Chester were going to send a new Gib, said I could experiment with the old one. Once I got it snug with the head at the bottom, it wouldn’t go to the top – it appears the column dovetails not parallel. At this point Chester immediately arranged a replacement, so well done them

New one seems good, cuts a lot better. On this one the movement tugging on the head is a couple of thou.

Only problem now is it is on my main bench (had to put old one back on the new pallet so there was some juggling) and is so much less wobbly than the stand I am tempted to leave it there…

[JonParticipant @jon]

Posted by Michael Topping on 01/01/2017 20:55:00:

I have a Warco super Major and if I have the column clamps locked it will cause the power feed motor to stall? I don't get chatter at all with reasonable depth of cuts etc. I have adjusted the column jibstrips a couple of times over the 2.5 years I have had the machine and it is possible to totally lock the column if you are too enthusiastic. I Don't get any movement at all from the column it's rock solid.

Michael

If you don't lock it down you wont know you have movement.
Everything I do I have to really lock the things down and there is substantial play in the quil casting worn oval through use.

OP the uprights do flex with the heavy head but can also dampen vibration a little. Unfortunately its a case of diy machines made to a budget, theyre all like it even 2 1/2 times dearer and something have to put up with.

Yes power elevation will lift or raise the head when gibs tightly locked down, careful knackered my transfer box 7 yrs ago doing that and £244 for a replacement when machine cost £930 new in 2004. Also have almost 2 revs backlash on leadscrew elevation, surprised still works.
All being well only has to get me in to August, paid for itself in a year semi pro.

Did look at means of reducing the weight of head about 11 years ago and substantially upping max speed which is intolerable at 1250rpm, not worth it due to cost and remachining casting for better spec durable bearings and down time.

Have used 4 Lux in total over the years and they all have same flexy bouncy bobbing head though cant see visually like you can a Wabeco, RF25 and everything else in between.

Can check the three nuts meant for angling the head but doubt it. Of course the 4 bolts clamping the upright column.
Also bed tilt towards ends of travel, convinced could detect a bow in mine, oh and lock bed down along with Y axis, makes a big difference.

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