Hi all
Yet another thread on a homemade mill spindle. But I thought that the project might be of interest for some.
I try to improve my mill spindle as the current is a bit slow, week and runs really hot. I can have about 2000 rpm with continous load without the spindle running superhot. Have not dared to test max temp but, I cant put my hand on it without buring my fingers off (that is rpm;s over 2000 with load).
So as I am anyways modernising to Mach3 i tought that I might give a new spindle a go.
The project is based on the X3 replacement spindle on Little Machine Shop. I was promised that the runout would be better than 0.01 mm, and the price almost nothing I thought I took a chance.
I did a bargain on ebay on precision spindle bearings and the only thing I had to do was to make a new shoulder for the bearings to fit on. The X3 spindle had a 30 mm and a 35 mm shoulder for the bearings, but I needed a 40 mm. The spindle had some material that I could machine away and make a new 40 mm shoulder for the bearings. This way the bearings will come closer to the tooling and thus make the spindle more rigid (right?).
To reduce the runout as much as possible on the new bearing shoulder I had it set up in the lathe with a ball bearing in the support-dock (see pic).
The new 40 mm shoulder came out some 0.005 mm too thin, that is 39.990 due to that temperature fell after I have sanded the last 0.01 of.. Grr. But I went on anyways.
I have now made the parts except for the housing. When I measured the run out I first got it within 0.004 mm. Great Success!! But I soon realised that further out on the ground axis on which I made measurements it was more like 0.02 mm.. not so good anymore. And worse, I could not repeat the 0.004 when redid the setup. Its closer to 0.02 - 0.025 mm. Crap!
Now, as a goal of the project I aimed at around 5000 rmp and perhaps higher. Do you think I might be able to remedy the problem somehow? Is here any hope or is it just the bin..
Lots of more pictures and details on my webpage:
The Spindle Project
Cheers
Per