Taper roller

I want to install some taper roller bearings on a shaft. My problem is that the force-bearing faces are on the outside - err, let me try and
explain that a little better:
. || || . ____|| ||____ face . | | . |/|| ||\| - bearing . | | . | | . | | . |\|| ||/| - bearing . ____ | | ____ face . || || . || ||
Normally the adjustment of TR bearings is done by nuts on the shaft which compress them together to the right preload, but in this case I need to push the bearings apart.
Can't thread the shaft and fit nuts inside as both bearings are the same size, thinking about an extendable tube on the shaft between the bearings or something, which probably won't work - help?
Thanks,
-- Peter Fairbrother
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Might sound like a dumb question.. Why do you need the bearings in this configuration.. Since the design assembly for taper roller bearings is the reverse.. Do they make taper lock taper bearings ??
Pannawonica ..

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 16 Mar 2010 00:27:07 +0000, Peter Fairbrother

I see no reason why two sleeves threaded into each other would not work. One with external thread and lock nut the other with an internal thread. What stops the shaft just sliding out of the bearings?
Richard
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
How about making a solid spacer and shortening it progressively until it fits - or making it longer 'til it fits either with shims or by remaking?
Russell
Peter Fairbrother wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 16 Mar 2010 00:27:07 +0000, Peter Fairbrother

Would it be viable to put both the bearings at one end back to back and a cylindrical or needle roller at the other end just to stop it flapping about? This would be a much more accurate design as the shaft length between bearings is minimal and so not prone to thermal expansion leading to changes in bearing load etc
Is this a quill? If so angular contact ball bearings would probably be more normal and can be obtained as a matched pair so the need for adjustment would be removed. Genreral arrangement as suggested above.
As with other Richard's query, how is the shaft located in the bearings - is there a shoulder somewhere? I presume you already have the shaft and don't want/can't chop it about much or you could do many things differently
Richard
--- ---
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If you can't push the bearings apart, can you compress their housings together?
Henry
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Dragon" wrote...

That was my first thought - a threaded cup at one end to hold the bearing outer race screwing into the housing, with a lock-ring to hold the adjustment, or if there's not enough diameter/clearance for that, threading the end of the housing and a screwed ring taking the preload to the outer race (perhaps via a thrust-washer), again with a lock-ring:
_ __| |__ _ | Z || || Z | lock-ring

(z = thread, excuse apalling ASCII art)
Rather like a bicycle bottom-bracket adjustment?
Dave H. -- (The engineer formerly known as Homeless)
"Rules are for the obedience of fools, and the guidance of wise men" - Douglas Bader
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Ancient Greek getting into the bath - I thank you all for the inspiration. Will post details later.
Unfortunately you don't get any of the money (what money???).
-- Peter Fairbrother
saving the world, of course - what else is new and worth doing?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

On the assumption that this project may be for the BCA, have you had a look at Ebay item 290409704479 ? Not for buying, the price is silly for domestic use, but to look at the high speed head on it.
Mark Rand RTFM
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Air turbine?
Dave
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Mark Rand wrote:

Well, yes and no - my original post was about the BCA spindle, which is about 2 thou out - waitaminnit, let me measure that
ok, 0.056 mm TIR - 2 thou, give or take
http://www.zenadsl6186.zen.co.uk/bcahead.png (2MB)
mostly because (hopefully) I was newbie when I made it. I'm thinking about replacing the spindle, using taper rollers etc.
The idea is to use an ER20 straight shank spindle, which is just about as long as - well, to the top of the pulley in the photo above. They only come in shortish lengths, and there isn't really much room for anything on the outside of bearing mounts (the two once-blue bits with small holes for grease nipples), and I'd like to put the bearings in between them.
But I got a idea inspired by a response to this thread which should solve a different problem (bearing arrangements for a rocket motor pump), which is a bit ... even more exciting ... :)
have you had a look at

Yes, it's on my watch list. Too expensive, as you say, but the highspeed head looks nice. Mind you, BCAs are ten grand plus new...
My highspeed head is based on a 54k 1/8" air grinder, with a little fettling to reduce endfloat:
http://www.zenadsl6186.zen.co.uk/highspeed.png (2MB)
The spindle is removed and the (red) grinder plus (ally) adapter are screwed into the bottom end (the hole in the bottom blue end is tapered, the adapter fits in the taper and the adapter nut is then tightened to hold the grinder in position).
Will probably do side-by-side spindles sometime, so I don't have to replace the spindle when changing use.
-- Peter Fairbrother
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.