Making a steady rest

[Mayhem]

(11-03-2013, 06:29 AM)stevec Wrote:

(11-02-2013, 08:11 PM)Mayhem Wrote: Next task is to make the pins to fit the roller bearings and I can progress to welding these into place.

You're gonna weld in the pins?

Nope - but I can see where the confusion crept in there Steve!

The pins are the last thing to actually make to finish off the assemblies. These will be a firm fit and then a set screw will be used to hold the pins in place.

Once that is done, I can fit the assemblies into the steady rest frame and ensure that all the rollers line up (there is a small amount of wiggle room built into the fit). Once I am happy, the small flange on the sleeves that are welded to the bottom of the assembly tubes will be welded to the frame.

[stevec]

OK, phew! I woulda thought a nice press fit of something like a dowel pin would have been fine (and replaceable too).

[PixMan]

Press fit isn't a good idea in this application because you find yourself changing knurls as they wear out or you might need a different pitch. There's only a couple of cycles of pressing in & out before the fit isn't press any more.

All the good knurling holders I've used had one set screw to hold the pin. That applies to the carbide pins (preferred) as well as steel.

[Mayhem]

I hadn't thought of using it as a knurler! I'd have to make it travel with the carriage if that were the case. I think I'll stick with bearings at this stage.

You are obviously working too hard hard and juggling work, family and maintenance on two houses Ken I'd suggest a ride on your bike to clear your mind (before the weather turns to crap)!

[PixMan]

My, amazing what happens when you are working on 4 hours of sleep in the last two days.

I meant bearings, and got something else in my head.

The pins for the bearings might need to get changed now & then, and to get a true press fit you'd be disassembling the carriers to get the pins in & out. Or, you'd be pounding on the pins from the side and I don't know how successful that would be. Ideally you want a snug sliding fit in the bearing inner race so that it doesn't spin on the pin, and loose sliding fit in the carrier.

[Mayhem]

I picked up a 10mm chucking reamer during the week and reamed the holes for the bearing pins. I turned up a piece of scrap so it was a slide fit in the existing holes and used this to line them up in my drill press. I picked up a small pair of v-blocks whilst I was in the US for use on my drill press and they have seen a lot of use since I returned.

   

Having not used a reamer before, I followed Russ' advice and halved the speed and doubled the feed (compared to a 10mm drill) and it worked a treat. The white stuff is a spray on cutting fluid.

   

When fitting the bearing into one of the carriers, I noticed It was really difficult to press the pin in. So I pressed it in without the bearing and I noticed that the slot in not perpendicular to the holes. I'm not sure how I messed this up

   

[EdK]

Oh, that sucks Darren. Weld and redrill/ream? Hopefully it's just one that you've drilled and the others are awaiting drilling/reaming.

Ed

[DaveH]

Darren,
That's a bit of a ......
May be it can be "adjusted"

DaveH

[mattinker]

Interesting project! I've been a bit nose to the grindstone these days, haven't looked in here for a while.

I like your triple plate set up for the hinges.

That's a real shame, your out of true on the for the roller pins. The rollers running true is really critical.

All the best, Matthew

[Mayhem]

Thanks for the comments. I'm sure I'll figure something out.