Warco ZX15

I,m having some problems with tool chatter on my Warco ZX15 vertical mill. I,m not happy with the round column on this mill, so before I trade it for a model with a dovetail pillar, could anyone suggest a modification that I could undertake to stiffen up the round pillar. I have spent some time looking and thinking about it but not had a eureka moment yet. I would really appreciate any suggestions.

Welcome to the forum Robert.

You could try filling the column with a mixture of sand/gravel and epoxy (google it) or just dry sand to deaden vibrations.

Allegedly epoxy granite has '8 times the vibration deadening properties of cast iron'.

Neil

Robert,

You may not bother reading all of this; but it's nice to know that the clever chaps at Cranfield think along the same lines as Neil.

MichaelG.

Robert,

I have sent you a PM (Thats Personal Message) which appears in the My Friends box towards top right.

The ZX15/Chester Champ Mk1/Axminster whatever round column was quite hefty, and since the vertical course adjust leadscrew was inside the column, cement is not the best advice.

Dennis

Thanks for your suggestions chaps, but as Dennis said, the coarse up and down lead screw runs inside the column. I will have another look at my technique to eliminate the chatter problem before I splash out on a dovetail column machine.

I considered buying the Chester version of one of these (the Champion) when they first appeared, but after a close inspection at an exhibition decided not to due the design of the head elevation / column arrangement.

With the head elevated as shown in the picture above, there is very little engagement with the column.On the example I looked at, the fit between the head mounting "sleeve" and the column was very slack & the clamping arrangement weak. As the nut for the elevating screw mounts in the top of the column & the screw enters the column when the head is lowered, the column cannot be filled to stiffen it. And that would not address the problem of poor fit between the head "sleeve" and the column, the lack of engagement at higher elevations & the poor clamp. The whole design and execution appeared flimsy and lacking rigidity. Add in that there are only 4 speeds and (IIRC) the lowest was 400 rpm, I decided to pass. That this design disappeared fairly quickly suggests that, despite being cheap at the time, it was no bargain.

The base appears to be a copy of the Emco FB2 design & it may be that this head / column arrangement was added to the FB2 style base to produce a cheaper machine than the 6 speed geared head, keyed column arrangement employed in the original Emco version. Chester also had a 3 speed power table feed for this machine that appears to be a copy of the Emco - I picked one up at a Chester open day & it fitted straight onto the table of my Taiwanese FB2 clone.

I doubt it will be possible to stiffen this arrangement, but it may be possible to replace the round column with one fabricated from, say 200mm square box section steel, with square sections welded on to provide slides & a new "saddle" to mate to the rotating joint on the current head. Not an insignificant project, but not insurmountable either - largely depends on what facilities are available to you.

Sorry to be so negative.

Nigel B.

I've had a ZX15 for over ten years and found the biggest cause of poor finish was vibration from the single phase motor. Changing it to three phase/inverter made a world of difference.

Russell.

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That's interesting, Russell ... and not unexpected

[it's great when theory and practice give similar results]

Simply looking at the general layout suggests that there will be just a few rather strong resonances; and if one of these is 'in tune' with the motor vibration the structure will 'sing'.

A modal survey would be educational ... but your experience indicates a simple practical solution.

MichaelG.

Not so much negative as critical Nigel B, I,m thinking that there is no such thing as the hobby mill that will not have some downside or other. Thanks for your response.