WARCO MAJOR QUILL REMOVAL

Thanks old mart,

I have to say the project has been one of the most enjoyable bits of work I have done for a long while.

TerryT

That was a useful week's work, Terry,. ..nicely done..

Thanks Diogenes II, Now on to the Edwin White improvement...

I have fitted a laser to my mill so I can accurately measure the angular error over a six metre distance before I start drilling /tapping holes in the column.

I will back that up with some dial gauge readings on the quill and then get out my drill.

I hope to start later today. I will let you know how it goes.

The laser is bolted to the head and has a 4mm wide 'target' 6 metres away. The dial gauge is obviously reading the quill position

Both methods have already been used by people to successfully reposition the head with good accuracy. ( Thanks to them for sharing the information ) I shall use those methods to measure angular error before I drill / tap the rack and column.

The mill table is 1 degree off horizontal so that will have an effect on the laser measurement at the ' target ' but with both measuring methods working simultaneously , I thought it was worth a test to see what accuracy / repeatability I can achieve.

Please tell me what you think...?

As ever I greatly appreciate any advice and comment.

Terry T

Your tilt measuring device is not sensitive enough. I was going to suggest that you match the tilt of the line to that of the table, but a tenth of a degree would be on the coarse side.

Assuming 4mm at 6 metres and reducing that to whatever your column to spindle distance is would give an approximate movement of the spindle sideways. Say the column to spindle centre distance was 333mm, then the angle moved would be 0.0382 degrees, and the spindle would move 0.222mm. I use the reflection back to the end of the laser which would double the effective distance.

It would be nice to find a laser with a smaller diameter beam, mine is similar to yours. Estimating the centre of the beam should give better results. Make sure the lens of the laser is clean.

Your dial gauge should be 90 degrees further around the quill, either direction, so that movement in line with the X axis is measured.

Edited By old mart on 13/08/2021 20:09:23

Thanks old mart,

I agree about the size of the laser dot on the ' target ' and will be contacting a friend of mine to see if I can borrow his laser rifle sight, in the hope it is better..?

Also, thanks for your advice about the dial gauge position.

Before I do anything, I will be clamping / shimming the rack , moving the head and testing / comparing the measurements to see how accurate / compatible they are.

Only when I have the measuring 'devices' working will I use them to determine the position at which I drill/tap the rack/column.

Best Wishes

Terry Y

One way of keeping the vertical movement is a version of the aircraft suspension, using a pair of folding links with close fitting bearings. They are normally fitted at the back of the column.

Thanks old mart,

There are indeed a number of methods., some quite complex but I want to try the Edwin White method at the moment.

I am sure that the Edwin White method will give sufficient accuracy for my needs , but I must get the measuring systems right before I carry out the process.

Since my last posting I have found my surveyors distance measuring laser which emits a much more powerful laser beam .............and a friend of mine, who was trained to work with precision lasers , is searching for one of his many laser emitters that can be focussed to give a fine dot on the 'target'. More about that later.

In the light of your last response though I will try to mount the laser on the centre line of the column so that angular calculations can be more precise...

It's great fun and stirring up some long forgotten trigonometry must be good for me...

Best WIshes

Terry T

That is the biggest problem with cheap laser pointers - the red dot is quite large with fuzzy edges - or mine seems to be at any rate - which makes determining the centre quite difficult.

I have just purchased a cheap mirror £5.50, sized 500x150mm, from Ikea, (delivered for £2 which saved a trek to the store, bargain!) which I am going to mount on a true flat backing board (ie not bowed like the present target) and mount vertically so as to refect the dot back to mill and try and get it to always return to a fixed target position and see how that goes. I think the problem will lie in getting the set-up right so the mirror is truly vertical and at the correct angle to hit the target, we shall see.

Old Mart - do you have a link to the folding links similar to aircraft suspension links please?  Sounds interesting!

Chris.

Edited By ChrisH on 14/08/2021 11:03:11

Chris, the top picture shows the folding links which keep the upper and lower parts of an undercarriage lined up with each other. I have seen this applied sucessfully to a round column drill mill.

Terry, you will get better results if you shim the mill where it bolts to the stand to get the bed horizontal. If you don't have a reasonable level, a ball bearing sitting on the bed should not move.

**LINK**

Edited By old mart on 14/08/2021 19:15:02

Edited By old mart on 14/08/2021 19:15:30

Thanks Old Mart - all is clear now, picture worth a thousand words and all that!

Chris

I spent my time today ensuring that my measuring systems were as good as I can get them before attempting to carry out any of the Edwin White process.

The ( expensive ) surveyors laser measuring device only gave a marginally better 'dot'.( The top one in this picture )

When used in comparison with the dial gauge on the quill I found that I could get results which allowed me to carry on.

I positioned the head .03mm off centre on the gauge and could see the core of both lasers displaced to the left line and return to centre when I 'zeroed' the head /guage position.

The object of the exercise is to measure the lowest position of the head and fix / screw the bottom of the rack there.

Then raise the head to its highest position, use the laser and gauge measurements to restore it to a correct alignment and fix the top of the rack there.

I have chosen to use two 8mm countersunk socket headed screws 40mm apart at each location to give the strength necessary.

Then I should be able to raise and lower the head and watch the laser dots track up the twin lines and watch any displacement on the dial gauge.

My mill is not horizontal on its stand so I will first measure the true extent of that error accurately ( thanks 'old mart'. ) and then angle the lines to the same degree so that the tracking is a true measurement of the head position. The guage reading should confirm the accuracy..?

Best Wishes

Terry T

Edited By Terry Turner 2 on 15/08/2021 20:12:08

I have found that even with a large size laser dot, that it is easy to estimate the centre. Of course, a tiny dot would be nice if possible.

I have completed the Edwin White 'improvement' on my Chester Eagle round column mill.

These pictures show results I have repeated several times.

Lower the quill to its full extent. Place the dial gauge in contact with the lowest part of the quill. Zero the gauge.

Lower the head using the worm gear. ( Approx 120mm movement ) Read the gauge - 0.07mm deflection.

I can't recall what the outcome was for Edwin White but for me that is pleasing. ( rounding things for errors in my measurement...about 3 ' thou '  in old money )

What do you think ...? Worth the effort...?

The process itself is fairly straightforward but there were some real traps on the way... !

More about that later

Terry T

Edited By Terry Turner 2 on 20/08/2021 20:02:13

Edited By Terry Turner 2 on 20/08/2021 20:03:49

0.07mm is a tad under 0.003" - I have to convert to thous so that it means something to me - which is not bad at all but I have to say I had hoped you'd get better than that! Is there a possibility of being able to micro adjust it? I am looking forward to reading of the traps you experienced, that should be informative.

I have this afternoon rigged up a mirror for the laser to reflect back onto a target on the mill, but not tested it in anger yet. I set the mirror as true to vertical as I could, I have a fairly accurate level, and then set the laser beam to reflect back onto the mill, it was way off the way I had set it before. Then I put a bit of masking tape over the place where the beam came back and drew round the laser dot to create the 'target'. Then I ran out of time to do anymore, but I will report back here what I find when I do check it out.

Chris

You might be able to fine tune the rack to loose some of that error. The other thing you could do is to take measurements at several points along the head travel and make a simple error chart which would account for the error. Exaggerating the 0.07mm on the chart would make it easy to read, and also work at intermediate positions. This would also work even if the rack was not exactly straight, 12 readings would be very accurate.

It would be interesting to hear from you how the modification was carried out.

Edited By old mart on 20/08/2021 20:27:30

I would have liked a slightly better outcome but the law of ' diminishing returns ' means that I could now put more and more effort into this head alignment issue but achieve proportionally less outcome.

My machine is after all a round column mill with all its defects and for most of my engineering the level of repeatable alignment I now have is sufficient.

I may well come back to the alignment question in the future and consider some of the more sophisticated solutions out there but for the time being I want to work on fitting a 3 phase motor, inverter and speed controller.

So, with grateful thanks to all those who have helped me, not least Edwin White, I will leave the head alignment question for further thought in the future.

I'll write up the 'traps' I found tomorrow, in the hope that they help anyone who wants to try the Edwin White 'improvement'.

Best Wishes

Terry T

Edited By Terry Turner 2 on 20/08/2021 22:34:02

Edited By Terry Turner 2 on 20/08/2021 22:34:39

Edited By Terry Turner 2 on 20/08/2021 22:36:33

The Edwin White 'improvement' appears to be a straightforward process capable of producing good results and greatly improve the head alignment problem with round column mills ..but... I found several elements of the work where I could have ended up with a poor outcome...

1/. The prospect of hand drilling four holes through the rack ( 11mm) and the column ( 17mm) and ensuring that the resultant hole was an accurate tapping size, then countersinking those holes in the rack, troubled me.

I removed the rack and used the mill to pre-drill two 6.6mm holes ( smaller than recommended for 8mm threads ) top and bottom ( 40mm apart ) and countersink them.

How did I do that when there was no rack on the mill I hear you ask..? Support the spindle/head on blocks of wood on the table before removing the rack, lock the head clamps and then use the quill control to raise or lower it, ( it is heavy..! )

I then had a pre-drilled rack which also acted as a guide for the holes I needed to hand drill in the column.

I ended up with very tight threads and good countersinks.

2/. My mill stand was actually 0.6 degrees off the horizontal so I had to incline my laser 'target ' by the same amount and I used an electronic gauge to do that accurately. ( Thanks to old mart for the ' heads up' on that. )

3/. The next, crucial , stage is positioning the head before drilling/tapping holes in the column and I very nearly made a serious mistake here... !

I drilled and tapped the lower of the four holes in the column and screwed the rack into position. I put the head into its lowest position and aligned the laser on target. I then raised the head to its highest position, moved it to align the laser/ target and prepared to drill / tap the crucial top hole.

BUT... somehow ....I noticed that when I moved the head up the rack, the rack did not appear to move at all... ? I would have expected the upward movement of the head to 'shove' the rack across as it went higher and it did not...???

There was a a 1.63mm gap between the head casting and the rack, which I was able to measure using feeler gauge blades and I then used those blades to make a shim to correct the problem. I recommend that everyone does this first. Edwin white uses a shim but appears to do it last...?

More to follow later

More elements of the work that could have produced a poor outcome....

4/. There are dangers associated with 'firing' lasers , even low powered ones, across a workshop but using one with a vertical linear 'target' proved to be very worthwhile. (If the laser is shone into an eye it can cause immediate, irreversible damage and when I was walking across my workshop I forced myself to look at the ground.)

I used the laser/ target to determine the rack positions and when I had screwed the rack to the column I used the worm drive/ handle to raise the head.

When I raised and lowered the head I expected the laser dot to track along the middle of the vertical target but in the middle of the movement the laser was wavering all over everywhere ?

I found that even when held top and bottom by two 8mm counter sunk screws the rack was simply not rigid/ strong enough and it was visibly flexing !

Fixing the rack with another 8mm counter sunk screw in the middle of the toothed section would leave too little metal so I decided to use a 6mm screw with the normal socket head which I turned down to a tight fit on a 8mm hole, which I drilled free hand. That stopped the rack flexing and corrected the error.

In the future I may consider using one of the other column mill head alignment projects that can be found on the internet but for the time being I shall stick with what I have.

Best Wishes

Terry T