# How do you accurately set adjustable reamers to a diameter?



## JAndrew (Sep 16, 2013)

HMEM,

I recently acquired an Atlas lathe with a good deal of tooling. Inlcuded with it was a set of 5 various size adjustable reamers.  It looks like the cutting blades are adjusted by threading the collars up and down the length of the tool to vary the diameter.

What I can't figure is how would someone accurately set the diameter that you're trying to achieve? You could measure across the blades with a micrometer or calipers but it wouldn't be very accurate as the blades have relief angles on them.  If you had precision hole gages you might be able to drop the reamer in but then you're relying on nothing more precise than a tight fit...?  You could ream test hole after test hole until you have it set right but that seems ridiculous.

Can these be accurately used or are they a novelty tool? Seems like fixed diameter reamers are the best way to go (although expensive to buy every size ever needed).

Thanks in advance!


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## canadianhorsepower (Sep 16, 2013)

JAndrew said:


> HMEM,
> 
> You could ream test hole after test hole until you have it set right but that seems ridiculous.
> 
> ...


 
*some time what look ridiculous is the way it's done* 

I have the complete set from 9/32 to 1.75 and like them allot
and like any tool in the machine shop
it's precise to the operator patience


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## Mechanicboy (Sep 16, 2013)

I has a set of adjustable reamers. To use the reamer: The hole must be undersize after the hole is drilled/turned, then ream up the hole until the surface is smooth and measure with inside micrometer or try to fit the shaft. If too little size, ream up in next step (adjusted with the collars) and measure/try to fit to shaft. It is a elaborate to use the adjustable ream, but it will give a precision size unlike the reamer with fixed size who can have a problem with exact size due worned cutting edge.


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## abby (Sep 16, 2013)

Adjustable reamers are not intended for use in machines , they are best used by hand with adjustment during trial and error fitting.
A typical application would be reaming vehicle king-pin bushes when fitting new pins.
For most model engineering work you won't need many reamers and if you buy them individually when required the cost isn't too great. Learn how to make your own from silver steel (drill rod) it is not difficult.


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## Mechanicboy (Sep 16, 2013)

abby said:


> Learn how to make your own from silver steel (drill rod) it is not difficult.


 
This is socalled "toolmaker's reamer"


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## JAndrew (Sep 17, 2013)

Thanks all for the replies.

It looks like Abby is right that these reamers were intended for hand use as they all have a square section on the shank end for a tap handle. I'll test them out this weekend on a test piece.

It seems like you'd have trouble keeping these aligned perpendicular to the work by hand unless the hole is deep or the material is harder.

I will read more about how to make reamers from drill rod. I need to know more about how to create a relief angle without ruining the tool diameter.

Thanks again,
-J.Andrew


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## ShopShoe (Sep 17, 2013)

I keep seeing adjustable reamers advertised by tool vendors, either in a print catalog or online, and there is usually a disclaimer in the description that basically says that the adjustable feature is to allow resetting after sharpening, not to provide a replacement for a range of fixed-size reamers.

Can someone explain further: I have been tempted to buy adjustable reamers to meet multiple hole-size needs. I have not bought any because of the caveat mentioned above. Reamers are something I buy as needed in the size needed to avoid the cost of buying a whole set of them for unknown future uses.

--ShopShoe


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## hi speed scrap (Sep 17, 2013)

Interestingly, I see no mention of the reamer guides so far.
I use adj reamers regularly, up to 2" dia, and never use them
without the pilot guides. 
I find them easy to use and great for sneaking up to an odd
size. Some of my reamers (about 30) have been rebladed, I 
don't bother resharpening them, just as cheap to buy new blades.
They are a great tool, but do need a little bit of skill to use.
I should add that some are about 25 years old and are Sutton
and P & N brand, ozzie made. 
Dave


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## canadianhorsepower (Sep 17, 2013)

ShopShoe said:


> I
> 
> Can someone explain further: I have been tempted to buy adjustable reamers to meet multiple hole-size needs. I have not bought any because of the caveat mentioned above. Reamers are something I buy as needed in the size needed to avoid the cost of buying a whole set of them for unknown future uses.
> 
> --ShopShoe


 
ShopShoe-------- adjustable reamer are like inch to 3inch long cutting tool.
the good thing is you can have a perfect fit,,, If you take time to measure
like you do when you use regular cutting tool on your lathe.  Here is a few pictures of mine used for a cylinder bore.
It's manual operation only
I also use the boring gage to check the fitness


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## portlandron (Sep 17, 2013)

I takes time to slowly creep up on the finish size you want. Work best when you can make the part to fit the reamed hole not when you need to ream a hole to fit a part.


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## jwcnc1911 (Sep 17, 2013)

In my opinion, and experience, adjustable reamers are more trouble than they're worth.  It requires patience which I have but the time to use such patience I do not have.  Also, they are useless for reaming a blind hole to depth as most of them have a great deal of wasted threads on the end.

Look how much Luc's stick out of that cylinder.

Mad respect for taking the time to use those Luc!


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## canadianhorsepower (Sep 17, 2013)

portlandron said:


> I takes time to slowly creep up on the finish size you want. Work best when you can make the part to fit the reamed hole not when you need to ream a hole to fit a part.


 
I don't think that in this hobby time is crucial
it's all about precision .Thm:Thm:

I know many machinist that are fast
they are the one with the biggest scrap been:wall::wall:


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## napoleonb (Sep 17, 2013)

ShopShoe said:


> I keep seeing adjustable reamers advertised by tool vendors, either in a print catalog or online, and there is usually a disclaimer in the description that basically says that the adjustable feature is to allow resetting after sharpening, not to provide a replacement for a range of fixed-size reamers.
> 
> Can someone explain further: I have been tempted to buy adjustable reamers to meet multiple hole-size needs. I have not bought any because of the caveat mentioned above. Reamers are something I buy as needed in the size needed to avoid the cost of buying a whole set of them for unknown future uses.
> 
> --ShopShoe


 
There are two types of adjustable reamers, the one which is discussed and pictured in this thread. This type of reamer can be adjusted a few mm in hole size. 

The other one is meant for adjusting tenths of hundreds of mm. It works by pushing a conical wedge into the reamer up front.


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## ShopShoe (Sep 18, 2013)

Thank You canadianhorsepower and napoleanb.

It looks like what I have been seeing is the second type. 

--ShopShoe


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## Boot (Sep 20, 2013)

I worked in a machine shop for many years and adjusted reamers by using regular o.d. mics.  Make sure the mics are calibrated and loosen the lock nut on the reamer , turn up the adjustable nut and set it like never a problem. Mic off the highest part of the blades.   Did thousands of holes this way with all kind of adj. reamers.  Drill your hole .015 undersize and ream away. No other way of setting them accurately. You could use gage blocks and other instruments but why would you?  Just my .02 cents.   Boot


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## Krutch (Sep 25, 2013)

There is a third type of adjustable reamer than previously discussed here.
It looks like a normal chucking reamer with an adjusting screw in the business end. That type is used until dull or undersize holes are produced, adjusted oversize and sharpened back to the required diameter. I believe it is a production tool designed to be used and resized several times before its' useful life ends. The range of adjustment is small and not for opening holes to an oversize condition, as the blade type or expanding types are.


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## Wizard69 (Sep 25, 2013)

ShopShoe said:


> I keep seeing adjustable reamers advertised by tool vendors, either in a print catalog or online, and there is usually a disclaimer in the description that basically says that the adjustable feature is to allow resetting after sharpening, not to provide a replacement for a range of fixed-size reamers.  Can someone explain further: I have been tempted to buy adjustable reamers to meet multiple hole-size needs. I have not bought any because of the caveat mentioned above. Reamers are something I buy as needed in the size needed to avoid the cost of buying a whole set of them for unknown future uses.  --ShopShoe



I'm always amazed that people will run out and buy drill bit sets with hundreds of drills in English, metric and what have you but refuse to buy a set of reamers.  I just see it as strange, yeah I know they cost a bit in a set but so do decent drill bits.   It seems like a condition that only applies to reamers as people will buy drill bits, end mills, center drills, taps and what have you in sets with no second thought.   

The thing is how do you know ahead of time what reamer may be needed for a project at hand?    I suppose with model engineering that is easier to figure out as the builds are well known often with good plans or kits.    I just find it funny that this mentality seems to be so focused on reamers.


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## Hopper (Sep 26, 2013)

One thing to watch out for when measuring adjustable reamers with a micrometer, is that the first third or so of the blades is tapered to "lead in" to the hole. So be sure to measure across the blades at the handle end of the reamer where they run parallel.


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## JAndrew (Sep 26, 2013)

Wizard69,

I think I'd have to agree that reamer sets might not be as big of an expense as thought. 

Here's a link for 25 reamers (from 1/8"-1/2" by 64ths) for only $160:  http://www.victornet.com/subdepartments/Reamer-Sets/1775.html

That's not so bad considering individual reamers will run you $10-25. And they have over/under sets also for slightly more.

Thanks,
-J.Andrew


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## weez (Sep 26, 2013)

I just got a 29 pc. reamer set from cdcotools.com for $95.  So far they seem OK.


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## wildun (Sep 26, 2013)

Wizard69 said:


> I'm always amazed that people will run out and buy drill bit sets with hundreds of drills in English, metric and what have you but refuse to buy a set of reamers.



I have found that the holes produced by drills can be highly inaccurate, caused by a multitude of cutting conditions like lubrication, materials, cutting speeds, feeds, and of course the big one - sharpening, how many people can sharpen a drill accurately? - not many!
Always drill undersize and use a reamer (if possible) when accuracy is required.
Yes, the adjustable reamer is very good at taking out a whisker at a time only, but it needs to be set squarely to the hole to be reamed and the best way to do this I found to do this was, when possible (not always possible of course) put the work in the chuck and line up the reamer with the tailstock centre and turn the reamer by a spanner or tap handle, following up with the tailstock all the time.
Once I became more bold, I actually did it successfully many times with the chuck turning and holding the reamer in a drill chuck! - however, one day I got ahead of my capabilities and wound the reamer up till it broke! 
This is definitely *not* the way to do it!


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## dman (Sep 26, 2013)

ive used adjustable reamers (the kind that is meant for being adjusted, with the 6 tapered blades) they work but it's all, mic it undersized, ream, measure hole, find the error, adjust ream again. it if you need them infrequently then maybe home made D-bit would do the trick


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