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Adjustable Reamers
- Thread starter Tomc938
- Start date
20 bucks/ton. I'll give ya 30...
Resist the urge to speed things along by powering the reamer with a drill motor! Bad things happen! 
Same goes for using them in a lathe or mill.
If you look closely at the reamer cutting edge, it has a quite long taper, often as much as a third of the blade length, before the straight portion of the reamer blade is reached. This is the actual cutting edge. If you are trying to set the reamer to a particular size, it helps to know this, as measuring off the taper is going to present you with issues!
The tapered conical bushing allow you to properly align pairs of holes or pairs of bushings, accurately. Pretty handy when you need that.
Look closely at the grooves that the blades ride in, one end will be deeper than the other, as it is a taper, to allow the size to be adjusted with the pair of nuts at either end. Back off the one in which direction (larger or smaller) you wish to adjust to, and tighten the opposite nut to slide the blades along the tapered seat they are in, to make a smaller or larger hole.
In my experience, you are far better off taking several light cuts than you are trying to take out straight to size.
Same goes for using them in a lathe or mill.If you look closely at the reamer cutting edge, it has a quite long taper, often as much as a third of the blade length, before the straight portion of the reamer blade is reached. This is the actual cutting edge. If you are trying to set the reamer to a particular size, it helps to know this, as measuring off the taper is going to present you with issues!
The tapered conical bushing allow you to properly align pairs of holes or pairs of bushings, accurately. Pretty handy when you need that.
Look closely at the grooves that the blades ride in, one end will be deeper than the other, as it is a taper, to allow the size to be adjusted with the pair of nuts at either end. Back off the one in which direction (larger or smaller) you wish to adjust to, and tighten the opposite nut to slide the blades along the tapered seat they are in, to make a smaller or larger hole.
In my experience, you are far better off taking several light cuts than you are trying to take out straight to size.
Tomc938
Ultra Member
Thanks for the guidance. I’ve never used anything like this, and with your description I think I could give it a try! I’ll need it for my steam engine cylinders in the fall.Resist the urge to speed things along by powering the reamer with a drill motor! Bad things happen!
If you look closely at the reamer cutting edge, it has a quite long taper, often as much as a third of the blade length, before the straight portion of the reamer blade is reached. This is the actual cutting edge. If you are trying to set the reamer to a particular size, it helps to know this, as measuring off the taper is going to present you with issues!
The tapered conical bushing allow you to properly align pairs of holes or pairs of bushings, accurately. Pretty handy when you need that.
Look closely at the grooves that the blades ride in, one end will be deeper than the other, as it is a taper, to allow the size to be adjusted with the pair of nuts at either end. Back off the one in which direction (larger or smaller) you wish to adjust to, and tighten the opposite nut to slide the blades along the tapered seat they are in, to make a smaller or larger hole.
In my experience, you are far better off taking several light cuts than you are trying to take out straight to size.
Tomc938
Ultra Member
Thanks! I’ve had a little luck, but the stuff is few and far between. And I’ll be sure to use some fluidVery nice score.
I've had good luck at re store at times.
Dont forget to use rapid tap or other light cutting lubricant
They are definitely a hand power only use tool! And are handy as heck to have on hand when you are sticking bushings into parts that require any level of force fit, either by cold shrinking or simple press/interference fit, which usually will change that 'perfect' sized bushing into one that the shaft or part will not fit through.
I spent an awful lot of my last eight years working, using these to open up holes which were then lined with a custom made bushing, or opening the bushings up to 'just' fit the pin that they were to have run in them, on mostly CF-18 flight control surfaces and other aircraft parts.
Tomc938
Ultra Member
If they can be used on aircraft control surfaces, they have a level of accuracy that far exceeds my skill level.
Sorry to have to say this, but folks got "Aircraft" confused in general with "High Tech". Especially in general civil aviation. The average Lycoming or Continental engine that putts around the skies has clearances you can measure with a wooden ruler, and an overhaul rate that would make a Fifties Chevy dealership slobber at the recurring income!
The CF-18 WAS pretty high tech...for a design that was essentially locked down in 1977 or 1978... Jess sayin'! LOL!
When I worked on them, the joke was that we would have to go to school for three years at least, so we could work on modern tractors or combines at John Deere, mostly to 'unlearn' bunch of bad habits! THAT would be High Technology!
In all seriousness, the capability to do good work, or bad, rests entirely on the user, not the tool. Practice, endeavor to do as well as you can, and endeavor to recognize how and when things did not work so well, as well as especially WHY they do not, along with some effort to not make the same mistakes repeatedly. and any work you choose to undertake, will be in good hands!
In our case, the original Maintenance manual, written to serve the US Navy's short term of service technicians, offered us only three sizes to choose from, before the flight control surface was scrapped or sent to a contractor for a major overhaul and structural repair. The Supply system did not actually hold the three specified sizes of bushings that the supposed 'kit' needed, so we made them as required. Mostly Beryllium-Copper alloy.
The Canadian Forces Techs soon figured out that using a dogs breakfast of various sized fixed and adjustable reamers, we could open up the hole that was worn, 'just' enough to make it round again, then make a custom bushing and install it, sometimes getting as many as a dozen repairs done before the hole was wallowed out to the maximum allowable size.
We played holy hob with a few OTHER supposed "Hard and Fast" rules as laid down in the aforementioned Tech manuals too. Like, we did a LOT of shrink fit bushings, using liquid Nitrogen.
The manual was VERY specific, in that it stated without any sense of doubt, that the amount of interference fit required, was ALWAYS 1.5 thou! The problem with that was, they specified the same interference fit on a five inch diameter bushing on the landing gear, as a sub-quarter inch bushing in the flight controls... People with a LOT too much faith in the Manuals, ruined a lot of parts! I was taught, and taught on, that a person had best to understand just how cold liquid Nitrogen was, and that they needed to understand how to find the coefficient of expansion (amount of size change, per degree temperature change), if they wanted to have even a slight modicum of success in shrinking bearings and getting them installed without actually doing more damage to the parts you were tasked to make serviceable for use again. For the smaller bushings, we could get away with FAR less than 1.5 thou of interference, and in reality, could not have achieved such, given the change in size, of a say, .250" OD bushing, even with LN2.
Essentially on the larger diameter bushings, you could reliably shrink the bushing enough so as to slide it into it's home without undue stress, but if you tried to use 1.5 thou on a sub-inch sized bushing, it would wedge itself in the hole, and rapidly lose all the cold you put into it with the LN2, and either ruin the part when it was removed, or worse, when the partially installed bushing was forced through the hole that it was way to large for...
Seriously. Stop doubting your capabilities. Practice. Pay attention. Try to understand why and how things worked or didn't, don't make the same mistakes too many times in a row!
Thinking your way through the process is always good. But do not allow the doubts to stand in the way of the actual attempts, or you will never 'do' anything! Failures are learning opportunities, always, as well as being opportunities to put problem solving to the test as well. "How do I fix this, now I KNOW it's Fooked?"
Proxule
Ultra Member
Thermal Expansion Calculator | Good Calculators
This thermal expansion calculator can be used for the calculation of the linear thermal expansion of any material for a specific initial length and variation in temperature
That’s been my experience as well.
As @trevj says, use a bit of science + common sense and you’ll do fine.
D
Yeah, a Thou per inch is a LOT better than the set standard of "always" 1.5 thou as spec'd in the manual!That’s been my experience as well.
As @trevj says, use a bit of science + common sense and you’ll do fine.
D
Especially in the quarter inch or so sizes that we were dealing with on such a regular basis!
I think sometimes things get lost in translation between the Engineers and the technical writers!
D
Do a quick favor! Look up a UNJ thread specification for me!
I think you will find that for all that Machinery's Handbook is good for as a reference, you will still need other sources!
Jess' sayin'.
And yeah, @Tecnico it does seem a lot closer to a Dilbert Cartoon, at times, between the Engineers. the Tech Writers, the actual Techs, and the Sales Weasels...
Tom O
Ultra Member
Here’s one wit different types of threads you can bookmark.