Enlarging A Reamed Hole

FREDROSSE

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When building a steam boiler, I had the tubesheets made, which use 1.250 diameter boiler tubes. The tubesheets came in with the reamed holes exactly 1.250, and I had trouble inserting the boiler tubes, the holes needed to be enlarged by a few thousandths. My only reamer was 1.250 also, so I put some 0.005 brass shim stock covering only about 1/2 the diameter of the reamer, and ran the reamer thru the 1.250 holes. Fortunately this worked very well, I was able to enlarge all 96 holes quickly, and then proceed with building the boiler.

Has anyone else made a reamer to cut a slightly larger hole with this method?

TubesheetStamping.JPG
 
I would have thought that the shim stock would have been eaten up when reaming. Good solution.
 
My only reamer was 1.250 also, so I put some 0.005 brass shim stock covering only about 1/2 the diameter of the reamer, and ran the reamer thru the 1.250 holes.

Hey FREDROSSE,

Neat on-the-fly technique; I am glad it worked out for you.:encourage:

To be considered as a go-to technique, could you comment on two points:
What hole size did you end up with? (did it expand by 5 thou?, likely the reamer cut into the shims too...)
Did they remain round?
-brino
 
Cool. Glad it works. May come in handy in a pinch.
What RPM? Drill press or mill or?
I imagine that the reamer pushed against the shim while cutting, so it must have been slow yes?
How was the shim placed? above the cutting end? below?
 
do you need to put the tubes int he header and expand them to fit and seal, I have seen that in large boilers at work.
 
I've done the same thing a few times, works like a charm.

Greg
 
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