Adjustable Reamers

I was sitting here thinking about a tricky mold build. Well tricky for me anyway. The solution is to cut the mold, assemble it, turn the
outside round, and drop it into a sleeve a few thousandths bigger to allow for venting, but limit flashing. I am pleased as punch about figuring out the solution to the problem, but that's not the only problem. I'm looking at target diameters of .997 and 1" respectively.
I don't own a reamer that big. No big deal. I could buy one and it would get here long before the job comes up on the board. I just didn't want to spend the money for one I would use one time in one hole and never use it again. They aren't cheap. Sure I pay that much for a fancy mill from time to time, but I get a lot of hours out of it, before it goes in the recycle pot.
Yeah, I suppose I could bore it on the lathe, but the sleeve has to be machined into a rectanguloid box. I also need to be pretty close on my tolerance. If I have deeper grooves inside it could flash, and if I get it to small it could seize or just not vent well. It would be kind of a pain to setup.
I'll probably 3D machine the sleeve half in each of two pieces to around 0.990 and then assemble and ream to size.
Than I thought... hmmm maybe I can borrow one from my dad. He has some old adjustable reamers. Maybe he has one that will cover the 1" range. He has a set and he offered to just give them to me. I asked him how much he paid for them and offered to pay for them since I will use it in my business. Yeah, you can give me some money if you want, but I only paid $25 for them. Never used the larger ones.
Nice. Two problems solved today. And even the solution to the solution.
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wrote:

IIRC I have some adjustable reamers down in the shop that I picked up at a yard sale preobably 25 years ago for a couple bucks. I think perhaps they were for king pin bushhings. Seems to me they were make and model specific but right now I'm too lazy to put my shoes on to go look!
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On 4/6/2018 7:05 PM, Bob La Londe wrote:

I used an adjustable reamer up my coal chute a while back.
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I suggest you try the reamer on scrap first. Perhaps my second-hand ones aren't sharp enough or I don't know how to use them, but they tend to chatter.
This may help both of us: http://www.toolfab.com/assets/downloads/toolfab-regrind-tips.pdf
-jsw
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On 4/7/2018 3:53 AM, Jim Wilkins wrote:
> >> ...> Than I thought... hmmm maybe I can borrow one from my dad. He >> has some old adjustable reamers. Maybe he has one that will cover >> the 1" range. He has a set and he offered to just give them to me. I >> asked him how much he paid for them and offered to pay for them since >> I will use it in my business. Yeah, you can give me some money if >> you want, but I only paid $25 for them. Never used the larger ones. >> >> Nice. Two problems solved today. And even the solution to the >> solution. > > I suggest you try the reamer on scrap first. Perhaps my second-hand > ones aren't sharp enough or I don't know how to use them, but they > tend to chatter. > > This may help both of us: > http://www.toolfab.com/assets/downloads/toolfab-regrind-tips.pdf > > -jsw > >
Actually they may not be any good to me anyway. This is going to be a blind hole, and from what I understand adjustable reamers have a very long taper. That just won't work.
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You are sending me email replies from a dead address.
"Actually they may not be any good to me anyway. This is going to be a blind hole, and from what I understand adjustable reamers have a very long taper. That just won't work."
http://imajeenyus.com/workshop/20150924_d_reamer/index.shtml
I made a D reamer that opened up the shackle bolt holes in hardened truck springs, after several failed attempts to temper it hard enough to cut without chipping, since I was drilling freehand under the neighbor's kid's truck. I smeared on Ivory soap to protect the machined surfaces in the fire. Grinding the flat to sharpen it removed the temper color so I can't tell you what it was.
I've made others unhardened ones to cut aluminum, for example a tapered air nozzle. It doesn't seem to matter if the flat isn't exactly on a diameter, at least when using it on the lathe.
You could grind back relief behind the cutting bevel if it doesn't cut freely enough. -jsw
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wrote:

'Hope it works. For future reference, if you don't need to remove much metal, an expanding internal lap with emery cloth will do it.
The best expanding internal laps have a long-taper hole and a tapered madrel inside of the, threaded on the end and edjusted with a nut. I've made them out of brass with a steel mandrel.
There are several ways to get emery cloth to stay in place on the outside of the lap, but I finally settled on just glueing them on in a spiral. They will tear a bit as you open up the lap, but it doesn't seem to matter much. I used Duco cement and just washed it off with acetone.
I've come to like adjustable laps for several types of jobs. Sometimes I even use lapping powder with them, but I usually try to finagle wet/dry or emery cloth to do the job.
It's crude, but it can really make a precisely-sized hole.
--
Ed Huntress

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