[corrie]

Hello all been away for a while but got a ?I recently recieved eighteen free bearings from thompson through a neighbour .They are 3/4" i.d. and 1.25 o.d.They call them super 12.Also I got two lengths of 60 case shaft 12"-two lengthes 24" and two lengthes 4'.what would be the best way to make a pillow block.I took the two 4' lengthes and layed them across the two ends of my machine but found out that there was too much flex and I dont want to cut them down,any suggestions.

[jeffs555]

Unless the bearings are the open style where you can provide a continuous support for the rod, 4ft is way too long for a 3/4" rod. With simple end supports, it will sag almost .02" just from its own weight. and each additional pound of weight will add around .005" deflection. If you build rigid cantilever supports for both ends, it will cut the deflection to about a quarter of the above values but is still an awful lot of deflection.

[Hobbiest]

Are you building your machine out of MDF, steel, or aly? If MDF, you could build your pillow blocks out of laminated layers of the MDF, with a 1.250 bore through for the bearing. If steel, have a machine shop (or friend, or if you have the tools) ream a piece of 1.250 pipe to remove the weld from the inside, then weld a piece of channel to the outside of the pipe for a flat mounting surface. A couple of holes drilled and tapped for set screws to hold the bearings in place, and a couple of threaded holes in the channel, and presto-chango alakazam, garbage has now becom a pillow block!

[corrie]

Thanks for your input gentlemen realy appreciate it but it seems i got lucky and won 14 star precision pilow block bearings on ebay that are the open type and are 3/4 in ., yahoo.They cost me 107.00 but worth it i think.It will make lining up things a little easer and I,ll be able to support the x-axes.The machine is about 42"long 24" wide and the z-shaft is 12".As I get back to re-configuring the machine I,ll post some pics.For any of you in or near Toronto, I,ve found two places for linear shaft and bearings and also lead screws.The first place is called metal market and the other is called oshawa bearings.Cheers to all and thanks to all.

[DR-Motion]

Hobbiest, I like the way you think... you don't make a hole... you find an existing hole and adapt it to your needs... lots less work.

Gary

[corrie]

Dr.Motion thanks.I tried the route of many home brewers ie: bearings on angle brackets,bushings with some kind of E.M.T pipe holders and just found that it was not adiquate enough.I understand about budget believe me,but after spending money on such things as what I mentioned and the time it took to put it all together ,I could have saved just a little more and done it right,but hey I think by trying those ideas just brings the mechanics of such a machine to a whole new perspective. I agree with symplicity but as I see it those that started out with the home brew ideas seem to have ended up where i am now.For anyone who reads this please dont get me wrong,you have no idea how great those home brew ideas have helped me along, but for me at this stage I just wanna rock&roll and get to the heart of the matter.Simply put cnc is what I,m shooting for and you gotta do what it takes .I still have a billion other questions and I haven,t even got to the electrical ,but hey one step at a time.Cheers Corrie.