Thread: Small spindle head
I have been lurking here long enough , so here is my project.
Small spindle head, un-ashamedly inspired by sherline spindles.
It probably would be cheaper, quicker and likely better to buy one, but ...
- it's not all about money
- here, in our Rip Off Britain they are slightly more expensive than in US
- I wanted to try an idea I had for bearings, different to those used in Sherline
- and of course for me, it's about making things rather than just buying lol
The rough plan (not fully detailed) is as follows:
The idea is to use for the main/front bearing double-row, angular contact ball bearing. The one I had laying around was 5204-2RS (OD 47.0 ID 20.0).
They are supposed to be good enough for 8000rpm (10000rpm with oil ?) and in design correspond to two single row angular contact ball bearings.
They can also accommodate axial loads acting in both directions.
They are supposedly C3 axial internal clearance... ?
That's theory and we shall see ...
The plan is to use this head with ER16 collets and various grinding, polishing, cut-off wheels on mandrels of various diameters, and if turns out any good maybe in future for other things as well.
I made the housing out of lump of alu I had laying around (again if it turns out OK, next one might be made in steel).
Both front and rear bearing housing have been turned in one operation, so whatever the accuracy of my lathe, they should be concentric.
And I have clocked side and bottom of the housing to make the spindle parallel to both (not needed for the particular application I have in mind for this head, but good exercise nevertheless).
I have turned the front at 46.98 and fitted the bearing by warming the housing in the oven and freezing the bearing (in plastic back) in our freezer.
It dropped in perfect and now is fixed solid and for life (I do not envisage ever having to take it out - it is sealed for life)
Rear bearing is simple 6203-2RS (OD 40.0 ID 17.0) radial deep grove ball bearing. I made the housing for it sliding fit and intend to secure it once assembled with Loctite.
Well, this is my cunning plan, and if it doesn't work, the loss will be minimal. In the meantime it is all good turning/milling exercise :whistling:
References to Loctiting rear bearing (highlighted in red in my original message) are clearly wrong and a result of my running in circles when thinking how to do the job. As rightly pointed out in the later message they rear bearing should be "floating".
Last edited by bambuko; 02-12-2009 at 05:48 PM. Reason: correction
Wish you luck with the spindle.
Keep us informed on your and its progress
thanks for paying attention
As usual it doesn't pay to cut corners when explaining things :dance:
a) I said about my sketch "... (not fully detailed)..." - I definitely plan to close it from the front (just didn't bother drawing it because I am not sure about details yet). Sorry if it has caused any confusion.
b) I also said "...It dropped in perfect and now is fixed solid and for life..."
This bearing has the housing heat shrunk on it - it is not going anywhere easily. And whilst I am planning to loctite rear bearing, I don't think I will need it for the front one.
And as for pre-loading the bearing - it is internal in the double row bearing so I don't need to (and couldn't) do anything about it. Ijust need to secure the bearing in place.
This is the experiment part of it - ie will the pre-loading inherent in the design double-row, angular contact ball bearing be good enough for this spindle?
If the double race is tight in the housing you could put a sleeve down inside so when you nutted the pulley on the top you pinched the double angular inner ring.
That'd do it.
Edit: I do have experience, here is a double angular bearing loctited on a spindle from my junk box
Last edited by Robin Hewitt; 01-12-2009 at 08:27 PM.
Sorry, I understand you now
The spindle is meant to be interference fit in the bearing as well, so this is as good as loctiting it, but I was also thinking about either a sleeve or a nut behind front bearing.
Most likely something like this:
Nice work, it will be interesing to see how you get on.
Have you seen the "Diy spindle design" thread? It might be worth a read as I seem to remember he had an initial issue with putting to much preload on it and it got very hot. If you have it adjustable then you can get the balance between removing play and to much friction.....
I'm interested to see what you are going to drive it with? I have the Er11 spindle but not tried to power it yet. I've got a 100amp esc and Rc motor but not sure wether to belt or direct drive it?
DIY Spindle design is one of my favourite threads.
Main difference is that he wanted high speed router at 20k rpm, my target is 5k rpm - my application is different.
My pre-load is not adjustable. It is set by the manufacturer of double-row, angular contact ball bearing that is used in the front.
If I was doing high speed spindle I would use the usual design of matched pair with adjustable pre-load, but I am hoping that at lower rpm I will get away with what I am proposing.
I eventually went for stretching the shaft between two singles with Belleville washers. I have become a big fan of Bellevilles since I started aiming for truly zero backlash on everything. A thrower ring on the base to keep the crut out and not overly generous with the oil.
I ran it up to 6000rpm then started winding the speed up on the digi phase controller. I was heading for 12,000 but started worrying about the belt driving it, felt pity in my heart. Probably be okay, but you do need a noise level that everyone in the shop can live with for those long cuts :whistling:
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