adjustable reamers - Yea or Nay?

[Messinger]

Many of the suppliers (MSC, Enco, etc.) sell adjustable reamers like the one pictured below. Has anyone used these, and would they be suitable for folder pivot reaming? I mean, are they precise? I have a batch of what are SUPOSE to be 3/16" pivot pins and they are 2 thou under. Using them with a 3/16" reamer makes for a sloppy fit. I was thinking about an adjustable reamer to tune in my pivot holes. I know you can buy incrementally off-size reamers, but they are expensive and you only get one shot. Being able to adjust by a few ten-thousanths at a time would be really handy. Thoughts?

-Ben

[Messinger]

I may have answered my own question. Looks like the smallest one has a range of 1/4"-9/32". Oh well.

-Ben

[Ray Rogers]

I've never seen one of those, interesting. I prefer to buy the off-sized reamers you mentioned. It really isn't as expensive as you may think. The trick is to buy your pivots 20 or 30 or more at a time. All those pivots should be the same size and it takes a long time to build that many folders (for me at least) especially if you also build fixed blade knives. Then, if you re-order pivots from the same source there's a good chance they will be the same size. If not, you'll probably find that they are the same as a pivot you got from that source on some earlier order. In other words, two or three of those off-sized reams may be all you ever need....

[Messinger]

Thanks Ray. Sounds good. I guess I was just a little dissapointed with the stuff I got. I bought 3/16" pivot pins and a recomended drill/reamer set to go with them from the same supplier. Right out of the bag the pivot pins mic out 2 thou under the reamer size and resulting fit of blade on pivot is dissapointing. Also, the pivots are anealed. Is that the norm? I would think that you would want a hardened pivot.

-Ben

[Ray Rogers]

Annealed is the norm. If you want it hardened you'll have to do it yourself. Of course, that process may change the dimensions by a thou or so also.

Rather than harden my commercially purchased pivots I just press a bearing into my blades. The bearing is softer than the pivot so it cannot wear out the pivot. In 10 years, I've never seen a bearing wear out either ....

[Mail4Tim]

Quite a number of years ago I using one of these rather often. It was somewhere in the 2.5 inch range if my memory is correct. They are great when you are trying to get a good tight fit on a non standard size shaft. The adjustments are very precise if you take your time and measure correctly. As you mentioned size is an issue. I've never seen one small enough to be considered as useful for folders.

Tim

[Kevin Wilkins]

I have a set of adjustable reamers. They are good for working on larger machines but are next to useless for something like folders with small size holes. If you buy any make sure you get them from a good company which will offer you replacement blades!

[Messinger]

Originally posted by Kevin Wilkins
I have a set of adjustable reamers. They are good for working on larger machines but are next to useless for something like folders with small size holes. If you buy any make sure you get them from a good company which will offer you replacement blades!

Yesterday I ordered one from Enco with a range of 9/32" to 5/16" to try on some of Darrel Ralph's precision pivot assemblies (pivot barrel with fitted bushing). The bushing OD is .310 and I am hoping I can use this adjustable reamer to tune in a perfect hole for that. If not I'll buy non-adjustable .310 and .311 reamers and try those (per Darrel's recomendation). If none of that works I'll relegate my cheap drill press to dedecated countersink work and go get a decent press. I'll report back on how the adjustable reamer works out.

-Ben