Mill Quil play before lock down

Hi,
ZAY7045-ZX45 type mill/drill.

I want to know exactly how I wind the quill down from a given point.

How do you deal with the quil play before & after you lock it down regarding the Z-Axis accuracy.

I bolt a sturdy bracket to the quil, then place dial indicator on it. I also limit the travel equal to the dial indicator travel, which now travel in reverse moving the quill down.

I can stiffen the quil play before lock down with a provided bolt, however even with this I dont get the indicator not to indicate a variation off the zero mark I set.

Now I cannot see how I can solve this as a result when fitting DRO to the Z-Axis.

How do you deal with this-?

I lower the head to put on a cut not the quill on my X3. Much like any larger knee mill where the table is raised to put on a cut keeping the quill retracted and locked for rigidity

+1

I only use the quill for drilling and boring. For all milling the quill is retracted, and locked, and Z feed put on by raising the knee.

Andrew

The ZX45-type milling machines aren't knee mills, they have a heavy head (inc. motor+gearbox) that slide on the column. I use the quill for small vertical adjustments, and lock everthing except the moving axis (and put *some* locking pressure on that one). There can be some slight judder on the head coming down, less so moving up, but it can be adjusted before starting a cut. Mine is used infrequently and I give all the slides a good oiling before using it to minimise slip-stick friction. I might make Z-axis readout using a digital caliper, to get a better sense of vertical movements; I wouldn't bother on X and Y axes.

Bill

That's is why I said "like a knee mill". Move a heavy head as I do with the X3 or move a heavy table, not much of a difference but keeping the quill protrusion to a minimum will help with rigidity and allow the DRO on the head to be used rather than fiddling about with a dti etc.

I have two of these and only recently have I noticed this problem. You cant move the head as its on a round column and when loose will revolve. I have taken to keeping the bit as close to the work as possible at start up, keeping a slight bite on the quill when lowering and then tighten it back up - not ideal I know.

Chris has a Dovertail column on his machine so no issue with the head rotating.

I have a Major mill/drill and as with yours I have to put on cut with the quill - sometimes it's easier to pull the work clear of the cutter, 'overshoot' the depth and then catch it at the right spot with the lock, on the way back up.. ..it's easier with a dro..

Although I haven't really done any 'fettling' of the machine, one thing I did do was to make a new dog-point bolt to engage the quill slot - the fitted one was awful, a p***poor fit, and hacked off at the end - a new one made the action less erratic& easier to predict.

My mill/drill is a HM-46 machine with a geared head and dovetail column and filled with a DRO. (another clone of the RF-45 made by Rong Fu and similar to the ZX45)

Raising and lowering the column with the crank lever on the column is a cause feed and I use the quill for fine adjustment.

I can lower the quill buy less than 0.1mm for fine cuts.. It does not change when I lock the quill.

Sorry, JasonB, I misread your intentions, and I didn't know that the X3 was a similar mill.

Bill

Thanks for the replies. What confused me, was the quill had a "fine adjust" which you engage specially to make that function work, that what lead me to use the quil for fine adjust face milling as experiment, I then soon realise it will be difficult to mill accurately this way.

The other way is the head dovetail use for up & down. I must say I forgot of the round column mill/drills, I had such an option(Cheaper) but for the reasons mentioned did not buy it.

I think I may have a selution then for the coarse adjustment by using the handle to crank.
-Some time ago, I gave it a thought to to add a 90 degree small gearbox in series with a car steering wheel universal joint, and maybe need a second one to extend that crank handle to the front like a knee mill.
-My choice would be a 1:1 ratio, but now on 2nd thoughts maybe another ratio for finer adjustment.
-Then instead of using the crank handle again, use a wheel to crank it.
-I will look at a wheat eater gearbox, not 90 degree, but angle I was offered for use some time ago, just did not get to it, it may be suitable or not.

Note:Another negative effect I noticed using the quill fine adjust, is if you lock it, and turn the small wheel engaged for that, the quill will not move, BUT however the quill may "fall" down a it to the turn you gave as soon as you release the lock, and ob some cutters this may cause a biting problem, more that you intended.....

-I think I am going to give this extention of the crank handle a thought again for the head adjustment, you get these small gearboxes in different ratios..

Edited By Chris Mate on 09/03/2022 23:04:57

Hi Chris,

Mine is the same mill and I always use the fine adjust knob to lower the cutter and don't have a problem. As I have said, I can do fine finishing cuts of less than 0.1mm. The fine adjust wheel has a positive feel and a slight turn will raise or lower the quill without any backlash. The quill height does not change when I lock it in position.

The RF-45 milling machines are designed by Rong Fu in Taiwan. Mine was made there but sold in Australia buy Machinery House as a HM-46. There are lots of other clones and I believe the ZX45 is made in China. I'm not sure it they are made to a different standard but I recommend the one I have.

One reason I went for the X3 is the head handle is at the front.

As for putting on a fine cut I can quite happily lower by 0.01mm so if Paul's example is anything to go by then still quite coarse.

I believe the Bridgeports as in what Andrew has also have a similar fine feed that can be engaged to lower the quill but he chooses not to use it except the autofeed for boring as do a lot of Bridgeport owners.

My memory is not as good as it used to be, and I did say less than 0.01mm, so I went to the workshop to check it.

I can lower the quill by 0.005mm increments and lock it in that position. I am using Easson scales which have a resolution of 5µm.

Chris, it is hard to tell exactly what you are asking about, is your quill moving a lot when you clamp it, or are you just asking about how to keep track of Z axis movement?

It is true that you need to take care not to wind down the fine feed while the quill clamp is engaged, the mental discipline comes easily once you have spoiled a couple of parts

The fine feed should have markings on the handle, same as the x and y, so in a pinch you can count those. Otherwise many of these mills have a cheap caliper type readout attached to the quill which while not as nice as a proper DRO is very useful, and despite mine having fittings which are not wholly convincing in their ridgidity, seems fairly repeatable. It looks like this one:

Another option is to improve the awful depth stop, as detailed by Stefan Gotteswinter here:
**LINK**

Stefan also later fitted a proper DRO to the quill, which can be seen in this more recent video dicussing other modifications:
**LINK**

Edited By Cabinet Enforcer on 10/03/2022 15:18:49

Hi, basicly I observe 2 types of play, and unlike the X/Y horizontal axis, you got something that wants to come down with the play involved, the return spring also play a role.(I will look further into this tention)
.
1-The play between quil rack/pinnion type gear, I can adjust this more tight, but tightness gives you a false imression of where the quil heigt may be, so if you misjudge, I believe a utter can pull it in soewhat depending on baclash left after you adjusted it stiffer-I now understand this trick.

2-The play between the fine adjust workgear mechanism. Now they have fixed pressed the round scale and it has 2x bearings. Not much I can do here, this play is in the design.-I now understand this too.

Because its vertical operation the quil/spindle will move, because you misjudge the direction of the play , and made the quil movement stiffer, then lock it down, in this case you may lock it down with unforseen play in the wrong direction, and a cutter may pull it in somewhat....I annot say I like this situation at all.

Note: I took the fine adjustment mechanism off and apart. It looks new & well made no play in bearings.
The grease was stiff not expected, so clean and regrease.

I will spend more time on this, then do a test cut with dial indicator fitted and see if I cut what I think I should have by measuring the part.(Face cutting)

Thanks for the replies. At the moment I cannot see how a DRO fitment to the quil(Z2) will be accurate here and to be trusted, I will look at SGW's version, the DRO will experience the same as my dial indictor, and yes the stop is the only real flimsy setup on this mill/drill. I did roughtly modified it(This was done few days after I fitted the mill)by letting it slip in an aliminium channell, and replaced the top switch(Removed) with a proper quality switch mounted lower portion secure to indicate the top of the quil position for tapping. This one ectually came with a broken top switch because of the flimsy stop, the stop just crashed the switch as it swivels around.

I did some thinking and going to try it out, the dial indicator will show if theres a difference or not.

I noticed compared to my 2 drill presses, that this mill I needed to help the quil back to top position a bit, I actually liked it so ignored it.

I am going to tighten the spring tention on the quil return quite a bit, so maybe it overcomes the 2x backlashes positively, and take the mistakes I can make in judging the position on fine adjustment and lockdown out of the equation, just maybe, I never thought of this before.

The quill on my mill has a fair amount of tension and If I release the lock with the fine feed dis-engaged and do not hold onto the drive levers, it flies up and bottoms out with a big thump. The strong spring tension could be why I don't have any backlash.

Ok, I think I made some progress....Play down from .1mm..........."Spongy/Leaky"........to .01mm.....more down to .......Zero movement. This is way better than  I experienced after doing the following:

1-I took the mciro-adjust assembly with wormwheel off, cleaned it thoroughly, inspect, I don't see problems with gears or play in assembly bearings.

2-I then properly greese the assembly wormwheel, and re-install this mirco-adjust assembly.

3-Now I rechecked, and found no difference, still .1+mm quil locked down.

4-Ok, now I relook at the spring.......Loosen it released.....With Quil locked at home position.
-I then crank it up to where the Quil/spindle move back to home position on its own.
- I then crank the spring further up 4x notches, stasrt to get real difficult.
-I then decided to crank it further up to the full turn, now this was not easy.

5-Ok, now I startet measuring again.

-----I saw/observe some "spongyness/Leaking" of the Dial indicator. Strange.
-------It behaved as I go down through 10mm differently at various depths down.

--------Sometimes I get .01 when I locked the quil, way better but not stable.

Result(Temporarly)=After cranking the quil up and down through the diall indicator 10mm travel, I noticed it became better and more stable.

>-------->My theory:

a)The spring tention play important role, although messing with the micro dial while quill is lock, is a risk, if you unlock the quil will jump to the setting you achived by messing with the micro dial.

b)The Grease:I think the grease I used may have caused the spongy readings initially, and as the greae was displaced on the worm gear it got better from .1mm+/- to .1mm to zero.


So some things to think about is the Spring tention of Quill as well as the Greasing of the worm gear assembly.
This worm gear assemble is all metal.
-Now I have to consider removing the grease all together in the work gear assembly, maybe the thinnest oil I can get...??

This is probably not the end of this, I must also find a way of getting rid of the play as in other mills of the drill stop mechanism, which is not good to begin with.

Edited By Chris Mate on 11/03/2022 15:33:12

Edited By Chris Mate on 11/03/2022 15:34:16

Edited By Chris Mate on 11/03/2022 15:37:22

Edited By Chris Mate on 11/03/2022 15:38:00

Hi Chris,

How old is your mill ? If its still under warranty, go back to the supplier to fix the problem.