Hello, I am attempting to make a long reamer. I have a 13/64" HSS reamer, and I wold like to drill a hole, approx. 0.125" dia. x .5" deep, do the same with a piece of drill rod, insert a dowel between the two, and silver braze them together. I am looking at the FIREX drills in MSC; will they do the job of drilling the hole in the HSS? Does anybody have any better suggestions? What I need to end up with is a reamer long enough to go thru an 8" long thru hole; no, I can't come in from both ends. Thanks in advance.
Anytime I have done this, I just grind a weld bevel on the ream and the drill rod then braze them together. Should not need to be perfectly straight or on center since the ream will follow the pilot hole. Of course the closer you get it the better.
put the reamer in a lathe chuck and the drill rod in the tail stock in a drill chuck. Tack them together, then remove and weld it up. Another possibility would be to grind or turn down the end of the reamer and use a drill bit extension that would fit through your hole.
Thanks for the tips. So really, I could just butt them together, do the brazing/silver soldering, and it should hold together? I would have thought that it would need a better connection...
After grinding a couple of nice weld bevels (0.050" per side), you should have enough surface area in the weld zone to allow for enough strength. Mostly you will be applying torsional force here. Not much lateral force. Not that much longitudinal force either. If you try to use the assembly as a pry bar, it would likely fail. Using it as a screw driver, it will probably hold just fine. Also remember, if done properly, reaming can be done as a hand operation, up to a certain diameter.
Again, thanks for the input, all information is appreciated. I have beveled the mating ends of the pieces to be brazed, and fixtured them in two small v-blocks. A little more information as to what I am attempting to do; I have 48, 8" long parts that I have drilled thru with an aircraft drill(0.187"), my boss is not happy with the finish, therefore I am attempting to clean up the holes with a left hand spiral, right hand cut reamer measuring 0.205". I plan on doing this in my HAAS mill; hopefully it will work.
Personally I would use the smallest ream possible that still gives the finish desired. But you are probably making do with what you have on hand since you are taking time to make your own extended length ream. You might be surprised at the results you can sometimes get by using the same size ream as the drilled hole. Just a burnishing effect of the same size ream can greatly improve finish.
Not sure what your measured hole diameter is, but jumping from 0.1875" to 13/64" (0.2031") will mean you are cutting 0.0156". This is close to the maximum amount you should try to cut for this diameter ream. If possible, I would suggest starting with either a #11 (0.191") or even a #10 (0.1935") ream and check the results.
You did not say material type, but because of the diameter difference, try to feed slow and make sure you get good chip removal from coolant or air blast.
The 13/64" reamer was the smallest LHS/RHC I could find; that configuration was suggested to provide the best surface finish, and to push the chips thru the hole. I failed to mention that 24 parts are CR steel, 24 are 304 stainless.
Straight flute would probably do the job just fine. But everyone has their own experiences and suggestions based on those experiences. Good luck with your project.