Sliding bronze bushings on drillrod

I don't know if it would suit your application but have you considered nylon bushings? I have seen them used a lot in the printing and bindery trade in light duty machines. They are suprisingly tough and any wear in the assy. is usually in the bushing not the shaft.

Just a thought

Sounds reasonable to me!

Sometimes, buying Thompson ground shafts and pillow block linear bearings is overkill.

CJ

Jim Stewart wrote:

Hey that sounds vaguely familiar... you buildin' a Gingery power hacksaw with various cast aluminum addons too? ;-)

I'm going to use a 50/50 solder mixed with 10% zinc for cheezy babbit bearings. Seems to slide well on the hardware store 1/2" galvanized shaft stuff.

Tim

Ewwww.. Have you no shame?

Regards,

Robin

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Those that suggested the Thompson shafting are spot on, unless you heat treat the rod (and grind/polish afterward) sintered bronze will not slide freely on the silver steel shafts.

------------------- I second the use of Thompson rod, and mount them by drilling and tapping the ends for a cap screw to hold the rods in place which would allow a slight adjustment. It is difficult to line bore all 6 holes so that carriage slides smoothly. Don Warner

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Greetings Jim, Freely sliding without "stiction" and without lube is what you want. Drill rod will actually wear pretty fast if it is exposed to much dust. Once scratched the friction goes way up. You can buy, for pretty cheap, the Thomson shafting and aluminum bearings lined with plastic. One of these is RULON. These bearings and pillow blocks are available in an open design where it is possible to adjust the fit by squeezing the bearing. If you decide to go with the case hardened shafting you can get, from MSC, a 16 inch long, 1/2 dia. piece for $6.82. 24 inches for $14.57. 7 inches for $3.05. And all sorts of other sizes as well and in the same price range. And a 1/2 id 1 in long rulon sleeve bearing for $4.21. This sleeve would need to be mounted in a block that you make or buy. MSC is on the web:

Look at page 3798 for the sleeve bearings P/N 354400399 and page 3870 for the shafting P/N 35522184 for the 24 inch long shafting. That's pretty cheap for a system that will slide real well for a long time and so you can concentrate on the rest of the project. ERS

Yes, but no money nor desire to bother a store any farther away...(two points which I know are a bit at odds anyway!)

Although I still feel I should ask why... just a hardware store prejudice? ;) It's smooth and measures pretty even, .498" or so.

Tim

-- "That's for the courts to decide." - Homer Simpson Website @

Raid an old printer or typewriter for shafts and bushings.

I don't know the details of what you are doing, but assuming a low speed application, even cold drawn mild steel with plastic or bronze bushings would probably work well

That's a great idea. Cheapest yet. And they do got some good parts in 'em. I've got an old HP 820C that finally quit after about 5 or 6 years of use in the machine shop. Replaced it and put it up in the loft as potential good stuff. Now I'm gonna relax with a beer and some screwdrivers and pull it apart. Cheers, eric

If the application is small (and I think this one was), old floppy drive mechanisms can be useful. The 5 1/4" usually had a nice little taut-band arrangement, and the old 8" drives (a bit hard to find these days) had a reasonable carriage, leadscrew, and anti-backlash molded nut, running on 1/4" shafting. And with a reasonable size stepper motor.

My cupboards are full of dismantled printers, plotters, and floppy drives, just for that 'one day...' time.

Roger

Eric R Snow wrote:

I really don't have a good answer....

Regards,

Robin