my build

[jonm]

hi kip
nothing wrong with agricultural take a tractor for example ... not the lamborghini of vehicles ... but it does what its supposed to do very well ....

think you should upgrade your bed:rofl:........

now

any ideas for securing 12mm lead screw without machining the ends
would this do

[irving2008]

hi kip
nothing wrong with agricultural take a tractor for example ... not the lamborghini of vehicles ... but it does what its supposed to do very well ....

think you should upgrade your bed:rofl:........

now

any ideas for securing 12mm lead screw without machining the ends
would this do

Are you using 12mm studding or 12x3trapezoidal? A 12mm ID bearing will sort of do, but the fit will be poor. Better to machine the ends down to 8 or 10mm for a good fit on a suitable bearing and thread them for a locking bolt. have you considered how you are going to manage end-float?

[jonm]

thanks irvine

using 12 mm trapeziod .. would the 2 grub screws in the pillow block not hold the screw against any lateral movement .... can the bearing take axial load ,.. was looking for a way round this as i dont have a lathe

[jonm]

built basic gantry this morning , threaded rod will pass through gantry sides bolting it all together , will also be bolted down through carridge angle iron(bed frame)

[irving2008]

thanks irvine

using 12 mm trapeziod .. would the 2 grub screws in the pillow block not hold the screw against any lateral movement .... can the bearing take axial load ,.. was looking for a way round this as i dont have a lathe

Those type of bearings are poor at axial load, they can handle some but are not good for locating the shaft axially, which is what is needed to minimise backlash. Somewhere you need thrust bearings to take the axial load or angular contact bearings (hard to get in small diameter ID).

[jonm]

cheers kip
good idea have some spare trapezioid will give it a go
with the grinder

[irving2008]

Oh I dunno...it depends what load you're applying. For instance...I'm using pairs of common or garden 15 ID 35 OD bearings on my mini-router....zero backlash and well within their capabilities....For machining metals....AB bearings only for me. Horses for courses Irving...after all the MDF router will fall apart before the bearings reach their limit :naughty:

Its not so much the bearings Kip, its the pillow block approach.. the way the bearing locates in the block doesnt give a positive position to the shaft. I'm sure it could be made to work for light cuts, but thats a fairly big router Jon's constructing so I'd assume he's got big plans for it ...

For machining try a drill and an angle grinder equipped with a flap disc in combination with a jig.

I accept no responsibility if you get whipped :D

these are long lengths of TR12, going to need some bearing support on those just to stop the whip, and thats before you put any pressure on with the grinder...

[irving2008]

I have no bearing location on mine.....the bearings sit against Al plate as they have no radial loads....a spacer in the middle and a belleville washer and a bolt glued in....Nice glue though ;)

I can't visualise this... picture needed...

[jonm]

hi guys
thanks for input ... fixed gantry to sides today, bottom runner in , all feels pretty rigid

[John S]

or angular contact bearings (hard to get in small diameter ID).

Look for magneto bearings, they are the smaller versions of angular contact bearings

.