Reaming Cast Steel Fittings without a Mill

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NP317
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Location: Northern Oregon

Re: Reaming Cast Steel Fittings without a Mill

Post by NP317 » Sat Jun 29, 2019 8:52 pm

Thanks for letting us know of your success.
~RN

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tornitore45
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Location: USA Texas, Austin

Re: Reaming Cast Steel Fittings without a Mill

Post by tornitore45 » Mon Jul 01, 2019 9:03 am

Enlarging 0.8 mm on the diameter is in the ball park of what a reamer of that size can do, and is the best option compared to all other you have tried.
The main problem is holding the part On Axis and preventing from moving and twisting. Slowest speed.
If you have a DP vise bolt it down on the table, place the part, center it by pressing down (gently) the reamer in the hole and clamp it there.
If you do not have a DP vise make a wood "cradle" with a collar on the vertical part that hold the part clamped and straight.

The wood cradle has a V cavity, and a thick board with a hole fitting on top of the tube you are reaming.

Good luck
Mauro Gaetano
in Austin TX

Mr Ron
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Re: Reaming Cast Steel Fittings without a Mill

Post by Mr Ron » Mon Jul 01, 2019 1:22 pm

Here is where a well designed jig is mandatory. It must be able to repeatedly hold the work in the exact same place every time. It must be able to hold the work without the possibility of shifting or moving while reaming. You must be able to use a slow speed and a lubricant. Since the fitting has 3 openings each to ream, you may have to make 3 jigs unless the part can be rotated to index each hole. In industry, jigs are always used. That is the basis of interchangeability. Jig making is a unique skill, but most people try to work around it with a "makeshift jig". I have done the same, but quickly learned the importance of a well made jig. I build model locomotives (pretty large) and require lots of identical parts. I will make a jig and it may take me 2 hours to make. I can then make 4,6 or 8 parts that will come out identical in 5 minutes. Let me add; although I use the term "jig", that what you need is really called a "fixture". The two terms are used interchangeably, but they are different.
Mr.Ron from South Mississippi

whateg0
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Location: Wichita, KS

Re: Reaming Cast Steel Fittings without a Mill

Post by whateg0 » Tue Jul 02, 2019 9:26 am

First, OP got it figured out.

Second, my take was that a reamer was being considered only because the other attempts had failed to that point.

Third, I know no tolerances were listed, nor end use, but I doubt extensive fixturing is needed for such a crude item. I didn't get the impression that this was a lunar rover being built. So, having a way to keep the part from spinning is really the only necessity. The drill will follow the existing hole.

Dave

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