Member postings for Robert van der Drift

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

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

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