How do I adjust the quill?

Is it possible to tighten the quill lock enough to prevent the drill being drawn further into the workpiece, then push against the friction of the lock until the depth readout says stop?

Alternatively, you could try the method I use with my Unimat SL. As it hasn't got a depth scale, I place a spacer on the table (in this case 0.5mm), loosely clamp the drill in the chuck, then set the height of the head such that the drill is pushed further into the chuck at the limit of the quill travel. Tightening the chuck whilst holding the quill against its limit sets the drilling depth exactly. Replace the spacer with the workpiece and drill.

Brian

No, there is no quill lock, only a depth stop that works on the pinion lever.

Subjectively, without dismantling the machine, it feels as if the quill is biased to remove all reverse backlash. In other words, it's as if the quill is heavy and rides on the rear of the pinion teeth - if the lever or the fine-feed is used to position the quill anywhere, it's quite easy the push it up by about 1mm.

In the final analysis I think it would be better, short of removing all backlash, to have forward backlash, as could be achieved with a spring to keep the quill pushed upwards, but then there could be problems when drilling through holes.

Sorry, but I thought from Ketan's post and the exploded drawing that the (M5?) cap head screw on the left above the fine feed (at 2 o'clock to the spring housing) pressed on the side of the quill in the same way as on my son's Seig mill.

Brian

Gary,

As I tried to indicate on 15-June ... I think it would be much more appropriate to adapt the machine to 'sensitive feed' [i.e. replace the backlash-ridden rack & pinion drive with a simple arrangement of pivoted levers].

I haven't schemed it out for this machine, but I can't see why it should be difficult to make a 'bolt-on' mechanism, to be used when needed.

MichaelG.

I reckon you're right MichaelG, thanks.

I've resurrected this thread because I thought it had an interesting outcome.

In the end I decided that the best thing was to replace the pinion gear, but, knowing it would be long job I put it to one side and got on with other stuff. Two days ago my conscience started nagging and I decided to dismantle the drill.

The cover opposite to the handle came off OK, but it was obvious that the handle and cover also had to be removed. The wound spring caused problems because it was riveted to the pinion spindle. I tried, and failed, to extract the spindle, so I removed the spring from the spring-seat. I still couldn't see what was retaining the spindle so I tried gently tapping it out from the other end. That did it. The spindle and gear came out as in the photo. It was when I checked the gear carefully that the problem was revealed. The gear is secured to the spindle with a little roll-pin, which didn't fit properly and allowed the gear to rotate a little.

I measured the amount of rotation as shown in the photos (sorry about the nasty angle) which turned out to be 5.3 degrees. The gear has 18 teeth and an OD of 20mm, so the 5.3 degrees translates into 0.833mm of free play on the quill rack, which matches very well with my observations that started this thread.

I haven't fixed it yet - that's the next job, then I've got to get the spring re-attached to the spring seat.

… The gear has 18 teeth and an OD of 20mm, so the 5.3 degrees translates into 0.833mm of free play on the quill rack,...

Pardon my lapse of memory but the old grey matter has decidedly slowed, would appreciate clarification on the formula / working out of the above.


George.

Pi times diameter times angular slop divided by 360.

Martin C

Thank you for the update, always good to know when a resolution is acheived.

Many thanks for the clarification Martin.

George.