[deaddave]

Some years ago I built a cnc router. Its been screaming its way through a myriad of projects since, but it's beginning to show its limitations. I've decided to build an actual mill, to a radically different spec. This one will be built on 60x4mm round epoxy granite filled tubing and 100x100x10mm H beam for the superstructure. It'll be big and heavy and primarily for metalwork. I'm still in the materials gathering phase so it'll be a while till an actual build thread is forthcoming.

One thing I badly need advise on is the spindle. I should mention, I live in Denmark, and that really narrows my options.

I want to build a cartridge spindle, belt driven, drawbar would be nice but its not a dealbreaker. I also would like something like a minimum 200mm between bearingseats.

I've seen quite a few builds on ERxx collet straight shank extension tools, but I cant find any of these over 180mm and in 30-40mm diameters I've not seen them over 150mm.

I looked at the SX3/X3 replacement spindles avaliable in littlemachineshop.com, and while absolutely usable, the final cost including shipping, import duties and tax ends up on the wrong side of 215$. Add bearings, stock for the housing and various odds and ends its just too expensive. This would be true for just about any spindle shaft costing in excess of 50$ and from outside the EU so...

I have one idea left. Attached is two pictures: one is an SK40 to MT3 drilling extension, and the other is a morse taper extension. What I basically need is a metal stick with a taper in one end, and these both qualify. I can get both of these in Germany, which is right next door. Both claim adaquate hardness and to be precision ground and both are avaliable in lengths approaching the ridiculous. Runout numbers I've seen on the tapers are also acceptable, but I can find no precise measurements on the outside diameters and surface tolerances. I'm thinking I could turn/grind down the outside taper for a pulley seat and shrinkfit on some bearings.


Any advise, insights or ideas would be greatly appreciated. I've been scouring the net for weeks and the above is the best I've come up with.

[neilw20]

The SX3 spindle (mine is R8) is quite serviceable.
Mine has run over 2000 hours at 3600 RPM, and quite hot at times, with no problems.

[deaddave]

I've heard other good things about that spindle, but the price becomes excessive for me because of all the extra costs. The 70$ price tag is quite reasonable, the +145$ I'd have to pay to get it here is not.

Do you know of any other places that sell a spindle shaft? I can find a hundred places that'll build me a complete spindle for more than I make in a year, but aside from littlemachineshop not a one who will sell me just the shaft

[davidmb]

There are some ER straight shank tool holders available, I guess this sort of thing would be availablefrom most tool suppliers, since they are designed to be held in high precision collets, the od is usuall to a good tolerance.

I only saw these after I started making my own cartridge type spindle ( they do say you live & learn - but I feel like I am bucking the trend sometimes, there are pics of my spindle in the gallery )

http://www.cutweltools.co.uk/files/w...%20Holders.pdf

C20-ER20-200M £69.23