38 replies to this topic

[Vipernoir]

I normally ask £25 per arm including a new pin and associated bits.

[jime17]

I normally ask £25 per arm including a new pin and associated bits.

Where abouts are you?

[A-Cell]

Nice to do it with the right tool, good price from Vipernoir. Hope you can arrange something.
Anyway to the other critics of course using the service tool is best and if you use a home made reamer you do it with the needle roller in to achieve concentricity, I thought that part was obvious.

[Vipernoir]

I'm just outside Bridgwater in Somerset.

No idea how much it would be to post a stripped bare arm - will try and find a spare and weigh it.

Edited by Vipernoir, 11 January 2013 - 10:04 AM.

[jime17]

Nice to do it with the right tool, good price from Vipernoir. Hope you can arrange something.
Anyway to the other critics of course using the service tool is best and if you use a home made reamer you do it with the needle roller in to achieve concentricity, I thought that part was obvious.

Thanks. A cell. Well said.

And thanks viper.

[dklawson]

Martin and John, rebuilt arms are a viable option for you in the U.K. However, at roughly $250 (150 GBP) each plush shipping they are financially out of reach for many in the U.S. That's why I made my own piloted reamer. There is of course also (as mentioned by jime17) the satisfaction of having done the work yourself.

As for the swarf, you don't pull the reamer back out. You load it flutes with grease, manually drive it forward guided by the needle bearing, and when the cutter starts to come through the bushing, you remove it from the chuck (if power driven) and pass it the rest of the way through and out. You do not have to pull the reamer (ans swarf) back into the arm. Guiding the ream by the needle bearings is not a bodge any more than guiding it with the counterbore for the bearing is. Yes... you introduce an extra layer of tolerance since you are working off the bearing instead of its counterbore but you still end up with a shaft that will pass smoothly through the bushing with the correct clearance and be concentric with the needle bearings.

[A-Cell]

Exactly. Well said. Great description.

[MRA]

Then maybe I should start making some bushes that can work with a conventional reamer to improve your quality.... PM me for details

[dklawson]

Martin, I've posted a picture of my radius arm reamer before but here it is again.

I tack welded the cylinder onto the reamer shank then mounted the reamer on centers and turned the cylinder down until it was a tiny bit over 13/16". I purposely made the journal a tiny bit oversized so it would be snug (but not tight) in the needle bearing. It has worked well for me and those I have lent the tool too.

EDIT: I forgot to mention that I positioned the cylinder on the shank such that it was fully inside the needle bearing when the tips of the flutes were just touching the uncut bushing. That way the reamer was fully supported by the time it started to cut.

Edited by dklawson, 14 January 2013 - 01:41 AM.