How to stay in control of mill depth of cut? (My mill has no fine quill feed)

Thanks Jo

N

Graham,

Yes, I realise I could have fixed it to the column - the only reason I did not do this is that I didn't think of it at the time! As far as the length is concerned, once I was fixing it to the base then I needed the backing and cover, and the marginal cost of increasing the scale length is quite small.

I haven't quite worked out how rotating the column would allow you to do a longer machining run without resetting; surely that is governed by the table travel. I could still tilt the head to use as a horizontal borer without rotating the column - not that I ever have. Perhaps I've just not been as adventurous as you have been!

David

Gray you need to bear in mind that what looks a 500mm long scale will only have a usable length of about 350mm as the head does not travel all the way to the.

So I would say David has 350mm of reading length. If the scale were mounted on a clamp around the column then the head could not easily travel to the bottom of the column.

The scales are sold by their readable length not their overall length so thats  more than likely a 370mm scale with and overall length of around 21"

Edited By JasonB on 13/03/2013 10:30:28

Just getting to know my new Sieg HM-10, yet to apply power to it, but it struck me that the adjustable lock on the dovetailed vertical pillar/slide could be used as a stopper once you had determined how much you wanted to take off? The DROs I read about above sound great

I do havea problem that while I have read and understood the dog-clutch mechanism for c hanging from ordinary to fine feed the indicator wheel for fine feed is not locked in the way I have experienced with other mills I have used. The supplier is at the other end of the country so I probably need to sort it myself, or learn how to do it properly .... suggestions most appreciated

I am not familiar with the Sieg HM-10, but it looks like one of the machines which Grizzly Tools sell in the US. They have an online manual for their machine, written in in American English, rather than Chinese English. I don't know if this might help you.

Andy

The Clarke manual HERE is up to scratch too, possibly better advice on actual milling - they are obviously upgrading their manuals.

The Grizzly one has scared me off using my mill now:

Neil

Edited By Stub Mandrel on 17/03/2013 12:24:59

What about something like this that is sold for the X3 mill ?

http://www.arceurotrade.co.uk/Catalogue/Machine-Spares/X3-Small-Mill-Spares

Top item, carries a stanadr 4" vertical DRO bar.

Thankyou all, Thankyou Andy that is a good link and a more informative manual than what arrived with the mill with its hillarious use of english There are small differences but my HM-10 looks very much like that in the manual. by Grizzly Thanks.

To all.

Concerning stick-slip of the slide on the main column:

As is mostly usual in hobby machines, the adjustment gibs are provided with small dimples and rounded adjustment screws in the saddle. Upon moving the saddle up and down, you can easily feel a bit of up and down movement of the gib itself. Consequently, with the gib riding on the rounded screws, the gib tends to bind and this causes the stick-slip effect. Also it is almost impossible to adjust the gibs as we would like to.

I solved the problem by drilling a 3 mm hole at a right angle in the left hand side of the FB-2 slider and straight through, into the full depth of the gib and fitting a round silversteel 3 mm dowel into the saddle and gib. I left the dowel about 4 mm sticking out so I am always able to pull it out using a vice grips. Being a bit lazy, I didn't want to dismantle the mill, so I did the drilling by hand. I checked the drilling depth and distance of the center of gib from the left back corner of the slide. In my case the drilling depth turned out to be 18 mm so check this frequently whilst drilling. After punch marking the saddle, I used drilling steps of 2,5 / 2,9 and finally 3,0 mm. Of course the pro's would take a 3 mm reamer at the end and use that, but the end result in my case was highly satisfactory and most remarkable. No more sticking and I could adjust the slide much better with less play.

Robert

The great George Thomas was an advocate of pegging gib strips.

Neil

Robert

I too have experienced the moving gib strip problem and carried out a similar modification to yours on my lathe cross slide which made a considerable improvement.

I will now check the Z gib (same as yours) on my mill.

It totally defeats me why some people refuse to drill a hole in a machine casting on the grounds that it is then non-original, each to his own I suppose.

Ian

Gray

In the absense of a suitable strip of cast iron would brass be as good, worse or better?

Ian

Thanks Graham and Ian,

Graham, your point about the dowels' insertion direction from the back side in stead of from the side is a very good one. I didn't think about that. Also your point about the c.i. gib. Thanks. I'll start a hunt here in the Netherlands for a suitable piece of c.i. and then change "for the better". And yes, parallel to the adjustment screws. My mill is a clone and not an original one. I was stupefied by the spindle bearings. Read the thread about it. Your mill must be ok by now. I honestly admire your work. I partly solved the problem with the single ball bearing top bearing by adding an extra simple ball bearing on top of the original one and adding a few shims between the two outer rings so these bearing are now under some tension. I know, those two bearings are not angular contact bearings but I couldn't find suitable ones as the diameter of the quill is only 52 mm and I could only fit 48 mm dia. Guess I have to change these bearings in one or two years then.

Ian, I do hope you read Grahams remarks. A mill is no Swiss cheese with lots of holes. Nor Dutch cheese for that matter. So position your dowel hole at the back side of the saddle.

Robert

Hello Graham,

Thanks for answering! Concerning the clone Emco FB-2 needle roller bearing: I could order this at SKF. Bearing # : NK 30/20 TN . I payed € 24,95 ex VAT for this bearing. The top bearings, as I have them now installed are 6005/ C2 and 16005 normal. C2 stands for extra tight fitting bearing. I have the 6005/C2 at the bottom and the 16005 at the top with a brass 0,004 shim between the outer races. I couldn't use two 12 mm wide bearings that's why I had to use the 16005 which is 8 mm wide. As far as I can measure, there is about half a thou radial slack in the needle roller bearing which I think is ok for the time being. I even tried to get oversize needles but could not get them. I use SAE 140 hypoid oil, mainly to silence the gearbox noise. Also I found out, that I had to adjust the gear shift forks inside the gearbox in order to get a quieter running gearbox. It is allright now. Of course I stripped the hub/gear joint of the top tufnol gear. That was a long time ago. It was just pressed in on the lightly nurled hub. I fixed it by degreasing the hub and the gear itself and gluing it back together with epoxy glue. Cured it inside the domestic oven at about 80° centigrade for half an hour. No more trouble.

I will heed your good advice concerning the slide gib. Now the gib in the slide (thank you!) is way too flimsy. The locating slots in the other gibs are much too wide on my mill. The gibs on the X and Y have about 1 mm slack in it. I think I will hand fit the slide gib in order to get maximum rigidity.

Robert

Gray

Your knowledge of these machines is impressive. Nowadays many manufacturers (or their agents) give out their own part number freely but rarely give generic bearing numbers let alone tolerances.

Going back to the gib strips, I am tempted by your recommendation that CI versions make a big improvement. When you say fill the gib strip space, do you mean making them 1mm (or whatever the existing gap is) thicker?

From my POV making a new X axis strip would require access to another milling machine. ideally I presume they should be surface ground too?

Ian

Gray

I can easily see how fitting new gibs to an X1 mill will make a significant improvement, in fact any improvement at all to an X1 is a big improvement!

I fitted ballraces on all the leadscrews and they made a truly dramatic change, I also relocated the Z axis leadscrew so its nut was clamped directly to the moving head rather than at the end of an 'L' shaped bracket out in mid air.

Going back to the Emco gibs, could you have eliminated the last stage of machining by mounting the slitting saw on the tilting head? also, where does one purchase cast iron in long strips?

Ian

Gray

I had assumed that you did not use the FB2 to make its own X axis gib strip as its table travel is always going to be less than the gib length. My suggestion of 'tilting head' was misleading though.

Ian

Doh!!!!!

My apologies Gray, I have even managed to confuse myself. For some silly reason I got it in my mind that the gib strip was on, and therefore as long as, the moving part of the slide. I have just measured my Mentor mill and the X gib is 300mm long and the table has almost 350mm travel.

I have not measure the gib section yet but it looks very similar to your drawing.

When I make new gibs I think I will put additional adjusting screws between the existing ones. My gut feeling is that more points of contact between the back of the gib and the supporting casting will increase the rigidity of the slide.

Ian

Gray

I do not have a manual for my mill but I am now wondering whether my machine should have the push rods in the adjustment holes? Your mention of them, and the fact that the existing (M6 Allen grub) screws are quite long at 25mm make me think that it might be worth fitting them.

I presume the holes are tapped all the way through so the push rod would only be sitting on the thread crests but since no real movement takes place it should not pose a problem.

Ian

I second Gray's comments about dowels into the gib strips. As to spherical ended screws, I had to go even further with a Chinese lathe gib where the dimples weren't quite in line. The gib twisted so much during adjustment that one end of it was forced down into contact with the slide base which, combined with the twist, made adjustment impossible. I ended up gripping the strip by its top and bottom in the milling vice so it was at 30°, flat-bottoming each dimple with a 3mm slot drill (and moving the out-of-line dimples over slightly) and making up new M4 adjusting screws with flat ends, turned down to 3mm over the last 3mm of thread. With a dowel at each end, the problems with adjusting the gib were solved.

Andy