Warco RF-20/25 Milling Machine

[Stephen OsborneParticipant @stephenosborne30223]

Quill feed problem

[Stephen OsborneParticipant @stephenosborne30223]

Warco Minor Mill RF-20/25

Vertical feed problem.

The above milling machine was bought new over 25 years ago but has had very light use.

When setting the quill height, I :

Raise lower the head to roughly the required height and lock off the 2 clamping nuts on the head/ column.

Tighten the knob on the tri-lever rapid feed.

Touch off by lowering the quill with the fine feed handle.

Set the vernier scale to zero and then apply the depth of cut and lock the quill with the ‘fixed bolt”

All seems well whilst cutting but on lowering the quill for the next pass with the fine feed wheel, the quill sometimes jumps down about 20 – 30 thou, often breaking the end mill.

Has anyone experienced this problem and could suggest a fix.

[OldironParticipant @oldiron]

I have an AJAX MD20 which I believe is the same mill. It has had a lot of use but I have never experienced that problem. Just been out to the work shop and set up a cut as per your post and looked for any play/movement and could find none. I even used a small pry bar between the head casting and quill but still no movement. The Ajax has a plate on the front of the head casting which can be removed to adjust the spindle backlash. I wonder if it is the tool holding that is the problem and not the machine as once the quill is locked there should be no movement possible.

Good luck in finding the problem.

[bill ellisParticipant @billellis45274]

Am I right in assuming that the quill jumps down as you are applying down feed with fine feed handle and not during the actual cut (with the quill locked). Could the locking bolt be binding slightly causing a hang up until gravity takes over? I'd take the two wedge shaped bits and the locking lever out and make sure there are no burrs or debris which could cause the problem. If it drops during the actual cut with the quill locked it must be as Oldiron suggests and is down to toolholding.

[dave le feuvreParticipant @davelefeuvre20236]

I am restoring a Naerok 350 mill at present and what you are describing is backlash, G. Turner did some mods, and to overcome what your describing he used tensator springs to take up the slack, you could use a spring system or pulleys and a weight. the drop you are getting means the gears are not in constant mesh, hope this helps.

[dave le feuvreParticipant @davelefeuvre20236]

I am restoring a Naerok 350 mill at present and what you are describing is backlash, G. Turner did some mods, and to overcome what your describing he used tensator springs to take up the slack, you could use a spring system or pulleys and a weight. the drop you are getting means the gears are not in constant mesh, hope this helps.

[Martin Hamilton 1Participant @martinhamilton1]

I echo what Dave has said, i have a Naerock 350 mill & the play is back lash between the rack on the back of the quill & the fine feed gear. Mine to has around 24 thou movement up & down on the quill, same as your Warco once you have taken a cut & undo the quill clamp lever the quill drops down the 24 thou pushing the cutter into the work piece. I have not broken any cutters with this happening though, i get around this by not undoing the clamp lever fully when winding the fine feed down to take the next cut. The slight clamping of the quill stops it dropping down & plunging the cutter in the work piece, but still allows the fine feed to move the quill down for the next cut before tightening the clamp lever.

[Stephen OsborneParticipant @stephenosborne30223]

Gentlemen

Thank you all for your helpful comments. On investigation, it would appear that the problem is backlash. The problem only occurs during tool feed adjustment – work & toolholding is not an issue.

I have stripped down and lubricated the quill locking system.

With the use of a dti, I can see the problem is a combination of backlash in the gears and the quill lock failing to release. Is there a way to reduce the backlash?

If I apply very slight pressure on the quill with the lock and then apply say 15 thou of down feed, the quill does not move. However on releasing the quill lock, the quill drops the 15 thou with a ‘clunk’.

It seems that the quill-lock must be completely free when applying feed via the handwheel.

I have also discovered that the vernier scale on the quill feed only has a passing relationship with the dti reading. I think for important work I will always use the dti to measure the feed rather than the vernier scale.

As an aside, I bought the machine at the ME Exibition with a reasonable discount – I have regretted it ever since as the build quality is so poor. I knew I should have bought a Bridgeport but you get what you pay for.

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