Warco Minor Mill Modifications

[Robert TretheweyParticipant @roberttrethewey]

I'd like to stop my Warco Minor mill from wobbling when the milling head is lifted via its rack.

I'd like to place in the rack 2 lower and 3 upper machined grub screws and be able to allow these to locate in holes drilled into the machine main column.

Has anyone done this and if so how successful was it in allowing the head to raise and lower whilst staying in the same vertical plane.

regards Dorsetearman

[Robert TretheweyParticipant @roberttrethewey]

How to stop the milling head wobbling when being lifted by it’s rack.

[Thor 🇳🇴Participant @thor]

Hi Robert

I assume it is similar to the Sieg Mini Mill, shimming the rack to reduce the backslash has been done. I havent tried it myself, I just tightened the gib adjusting screw.

*** Link ***

Thor

 

 

Edited By Thor on 04/06/2016 16:32:07

[NJHParticipant @njh]

Robert

To clarify – are you proposing this as a way of maintaining alignment in the 'Z' axis when moving the head?

Norman

[Robert TretheweyParticipant @roberttrethewey]

Reply to Norman

Yes. By making a set of drilling jigs so that when the rack has been reassembled, after drilling and tapping the grub screw locations in the rack. Then by locking the head in the axis where it is at 90deg to the horizontal table. Then by using the drilling jigs produce a pilot bore followed by an enlarged hole which may be honed to final size. Then using grub screws with machined cylindrical tips to suit the honed holes in the main column; I should be able to ensure a fairly accurate vertical plane when I raise or lower the head using the rack. If I want to swivel the head I would merely remove the grub screws and allow the head to float as it does now before being locked in position.

regards BobT

[RobboParticipant @robbo]

Bob

A solution similar to the one you propose was used by Yves Rayssiguier (from Brest) and detailed in MEW no 50 in May 1998.

The basic premise of this was to fix the rack to the column.

I can make you a copy if you PM me with your email address. It is 4 pages so pdf is more appropriate, but cannot be attached to a PM.

[Robert TretheweyParticipant @roberttrethewey]

speech clarity (all one word no spaces) at hot mail dot com will reach me

[NJHParticipant @njh]

There was an article, some years ago, ( maybe in the "other" magazine ?) which consisted of a tapered and hardened tongue being fixed to the head. Clamped around the column was a plate carrying two ball races with a space between then. The head was clamped to the column and the plate moved up so that the ball races were tight on the taper. Work proceeded and, when tools needed changing, the head was unclamped and moved up, tools changed and the head lowered until the tongue was again tight on the taper. (I made 3/4 of this then was diverted – maybe I will complete it one day!)

Norman

[VicParticipant @vic]

I don't know why but I'm lead to believe these type of mill drills don't suffer from the same problem.

**LINK**

The head is fixed to the column which moves through the base but this on its own surely can't account for the improvement? Perhaps there are other features it has you could incorporate into you machine.

[Robert TretheweyParticipant @roberttrethewey]

Thank you Vic for your Post I don't think that this mill design suffers from the same amount of wobble that the Warco/Grizzly/Pinnacle type milling machine does. I will, however, read the article with interest.

Regards dorsetearman BobT

[NJHParticipant @njh]

Vic – that's like comparing a Lorch with a Unimat !

Norman

[duncan webster 1Participant @duncanwebster1]

A much simpler solution, which has been described elsewhere, is to fix a laser pointer to the head and draw a vertical line on the opposite wall. Then when you adjust the head up and down, just align the laser dot with the line. Put it above eye height if you can, even quite low power lasers can do your eyes no good

[JonParticipant @jon]

They will all move no matter how tight the tolerances are kept whether above Ixon or RF25. Few thou clearance on small footprint rack = loads of rotational

[Martin ConnellyParticipant @martinconnelly55370]

Jon has pointed out the problem with relying on this type of system. The ratio of the radius to the rack versus radius to the spindle is the problem. One may be seven or eight times the other. This means that the error at the rack is multiplied by this ratio at the cutter. An error 0.05mm at the rack may be 0.5mm at the cutter. You may be better off just picking up the x axis setting by some other means, you can ignore the y axis error as it will be negligible. A simple method of maintaining the x axis setting is to clamp a square to the table, mount an indicator on the head in contact with the square and set to zero. Raise the head and adjust x back to the point where the indicator reads zero and you have the spindle correctly set to carry on.

Martin

[Robert TretheweyParticipant @roberttrethewey]

Duncan and Martin

I bow to your experience and knowledge. I had not considered the difference in the ratios of the column dia to the fixed distance between the column centre and the spindle centre the difference in the ratios of both multiplying the error achieved.. Thanks to both of you for pointing out alternative thoughts and considerations.

I am currently making a new depth gauge/stop which was broken off when I bought the machine, I shall now modify my designs for this to incorporate the dial indicator suggested by Martin. The idea of a laser is useful however the machine would need to be bolted securely to the garage floor to avoid machine creep and this I did not want to do.

Regards to both of you for your ideas and suggestions.

BobT (Dorsetearman)

[VicParticipant @vic]

Posted by NJH on 04/06/2016 20:32:33:

Vic – that's like comparing a Lorch with a Unimat !

Norman

The Ixion is a German copy of the earlier Korean mills from the likes of Naerok. As said the height adjustment works differently from all the Chinese mill drills that came later. Quite why the Chinese didn't copy the design exactly I don't know but they don't work nearly as well in terms of registration even with the Naerok.

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