z axis rods and bearings...

[project5k]

im considering using using some 20mm (roughly 3/4") rods and bearings for my z axis... I'm looking to have about 8 or 9 inches of z axis travel, so i was thinking about getting this 30 inch rod, cutting it inhalf, and then getting one more of these bearing blocks... whaddya think? will this be strong enough for my 3'x3' router? i'm planning on using a full size router, maby a Portercable or soemthing similar... also, i was thinking about how to mount the rods... i could mount them side by side, on either side of the router, or at a right angle to the router... hopefully the attached picture will give you some idea what i'm talking about...

http://cgi.ebay.com/ws/eBayISAPI.dll...2531&rd=1&rd=1

[wcarrothers1]

Call me crazy but I can't figure out the drawing..

But you have seen my design. I used 3/4" rods for my project..

Here is the cheepest place I found to get rods. Not the fastest shipping but they only charged me 40 bucks shipping for 2 - 60" by 1" thompson and 2 -24 (i think) 3/4" rods.. http://www.qbcbearings.com/RFQ/Defau...e=B612Main.htm

Anyway in my design I'm using 3/4" the shafts are perhaps around 20" each after being cut down (have to double check that) and have 4 bearing blocks. I have sections of 1" and blocks for those from the other assembly I got off ebay. Anyway I'm considering upping my desing to use the 1" to decrease flex. I'd be tempted to stay away from the MM sized shafts and stick with inch ones if ya can (unless ya are out of the US or something)

One other thing I WISH I saw before cutting my rods down.. One design I saw.. Had the rods extending extra length out the top and the guy built a motor mount that clamped to the extra length and between had his love joy. This second clamping section could have been made (for me) at the same time I made the main end plate for the assembly and if the rods extended longer I would have instantly had an adjustiable perfectly aligned motor mount vs having to make the box type I ended up making.

Probably hard to discribe and of course I don't have a link to the picture I saw.. Hopefully that is a good enough description anyway.

b.

[project5k]

while i agree that the actuall shafts are cheaper from there, the bearing blocks are way more expensive that what i have found on ebay.... metric or standard dosent really matter to me, just so long as they work together and are nice and accurate...
in the picture, the oval and middle circles are the router, and the little lines and spots/tiny circles are the shafts... i can see 3 ways to put my 2 shafts, and i was wondering if anyone had considered doing it any way other than just having the 2 shafts right next to each other...

[wcarrothers1]

I got my shafts from that company and I got my bearing blocks off ebay.

If I upgrade my shafts I'd have 4 blocks I'd be able to sell.hehe

Not sure if I can figure out the pictures still but not sure why you would want the shafts off set (the right most version) behind alows the router to vary it's size with out getting in the way of the shafts. Having them on either side might be the stiffest but if you later put in a monster sized router. Also might get hard to access the on off buttons and what ever else..

b.

[project5k]

well i plan to have the on/off mounted on the side of the router near the rest of the controls like the jog and things of that nature. that is if i dont go with a computer controlled spindle, which im thinking about...
ok, so i found this as well... whaddya think, it works out to about the same price, but dosent have quite the same travel... but its all done, all i gotta do is mount it and presto, no aligning rods and all that mess....
http://www.deltron.com/catalog/produ...=46&prod_id=72

[wcarrothers1]

load cap of 40lbs could be a problem..

Don't know how much your sutff weighs but my servos are 10+ lbs alone. My router is no light weight either but I'd say that at full extention that would pivot or something.. Although as I'm thinking about this you are probably thinking of doubleing them (ie one on each side)

If that is the case perhaps ok.

b.

[project5k]

well i just snagged a setup off ebay, so i'm gonna see what it looks like when it comes in and go from there....

Item number: 120041219167

[andy_ck87028]

Hi

I inherited 10mm shafts and hope that they will be adequate. If not, I'll put it down to experience.

Because the rods could be undersize, I didn't want the conventional arrangement of two rods behind the router as the weight of the router would introduce an unwanted turning moment.

The arrangement I have settled on is shown in the diagram below. I have used three rods in a triangular arrangement (dark blue) with a threaded rod (red). The router is pale blue.

I believe I will get optimal strength. It is mostly manufactured but not yet assembled. With router attached, it is very well balanced as can be seen by the pictures below. Only the side rods are attached. I have yet to attach the rear rod or the threaded rod. The slide block for the rear rod will be on the main assembly as distinct from the slide blocks for the side rods which are clearly seen on the router assembly.


Andy

[ger21]

I got my 3/4" SS shafts and bearings on Ebay. Bored my wood Z axis and popped in the bearings. Works great.
http://www.cnczone.com/forums/attach...3&d=1136858794

[wcarrothers1]

My stage plate on the back is a DSRC - 16 incase anyone was wondering (from the 4x8 pictures thread)

I'm guessing (have to look it up) the dscr-8 is a half inch or 3/4 rod supported statge? Should be very ridgid either way.. I'm pretty happy with mine after I got those supports.

Only down side is the amount of room for the ball screw. I ended up cutting out the ball screw tunnel on mine and making my own mount.

b./

[project5k]

yea i was looking at the screw tunnel on this one, and may end up having to either drill it out or cut it off and make my own, either way, im thinking that this sliding stage arrangement will be the easyest for me to set up.. all i gotta do is get it plumb, and not have to worrie about the rods being parallel, and all that... i'll just have to wait till it gets here to see how much slack there is in it, and if ic an clean the rust off that one end... anyone ever tried to clean thoes rods? to get the rust off i mean? any suggestions.. i was thinking WD40 and some 800 grit... hopefully that will get the rust off, but not dig into the rods too much and cause a slack condition when it moves over that area....

[wcarrothers1]

Not sure about cleaning the rod.. But should be real ridgid..

And if the bearings are worn out they can be replaced as well since they slide in and are held in the stage with a pin..

That was a good find though even if you need new rods. I paid 80 some bucks on ebay for my first dscr stage. Course the second one I found was a stage, 40" of 1" rod the supports for the length, a 12x48" by 1/2 plate of alum, and a 1" thick ball screw 50" long or something.

No idea what to do with half of that suff but only cost me 125 bucks..

Keep building..

I'm hoping to have my leg cross braceing in tonight (ran out of welding gas last night) then onto mounting the table..

b.