Reaming Cast Steel Fittings without a Mill

[spro]

So I spent some time looking at reamers which expanded from the back. McCrosky is one. You need a range of whatever. This is all bogus because nobody puts a selfie like that. I was thinking about eye protection and gloves or no gloves, Tee bars until it dawned on me that we are being played. It has been an interesting ride. I still hope the project goes well sir.

[Rich_Carlstedt]

Without the proper power tools, it becomes a difficult job.
First suggestion - easiest without power tools
Tapped the holes 30mm , and cut threads on the pipe. It would not be a full thread, but who cares.
Second suggestion
The reason for the "Stalls" is you are taking too much stock , which is known as feed rate (FR)
You have to slow the FR down , and one way to do that is to fill the cavity with another substance . Maybe wooden plugs ?
That way a drill will have much greater resistance and not "Plunge" into the cavity.
Third suggestion
Clamp A vise to your drill press table. Mount castings in the vise and use a 29.2 mm rod in the chuck to accurately center the part.
Remove the rod and replace with the carbide core drill you pictured. Do not use the core drill centering drillbit as you do not want to drill through the casting, so insert a dowel pin in the coredrill and leave it loose. Place a 29.2mm plug ( 3 to 4mm thick) in the hole and have it centerdrilled with a hole matching the dowel, so you use the dowel for holding the cutter for the start of the job. Set the "stop" for the drill press so the coredrill just hits the part. start the drill press, bring down the quill and use the quill stop as a way of controlling down feed. Put a needle nose vise grip on the stop and you should have the ability to slowly advance the cutter downward.
Not pretty, but effective.
Rich

[John Hasler]

instead of opening the hole...can you turn DOWN the pipes????

That's the best idea yet.

[Harold_V]

I was thinking of a rigid hone, but it seems that they are as pricey as reamers. I did find this, though:

https://www.ebay.com/i/302458935622?chn ... gIsXPD_BwE

Even with a rigid hone, progress would be dreadfully slow.
In regards to the link, they would be of no use unless the hole in the object shown are through, and I suspect they are not. Hand reamers have a long taper, which does the cutting, while a chucking reamer cuts at the very end, at the chamfer. With a hand reamer, you might enlarge the hole to some degree, but with a taper.

H

[Steggy]

If accuracy truly matters, I don't see how it can be done with anything but a reamer. The real problem to be solved is how to hold the piece so the bore being enlarged is exactly concentric to the drill press spindle and stays that way under the considerable torque that will be applied as the reamer "digs in."

Also, a 30mm (1.18") diameter reamer has to be turned at 150-180 RPM to achieve optimal results in most cast steels without overheating and damaging the cutting edges. You likely would need a geared drill press for the job. Even though belt-driven drill presses capable of such low spindle speeds exist, most will have belt slippage problems in producing the torque needed to drive a reamer of that size.

[Harold_V]

If accuracy truly matters, I don't see how it can be done with anything but a reamer.

Holding the part would be the biggest problem, but that could easily be handled with a simple shop aid fixture with a pair of telescoping and locking members located @ 90° and parallel with the base. The part would be indexed three times. With the piece in place, the telescoping and locking members alone should hold the piece in proper orientation and be rigid enough to permit a cut with a boring head. A reamer would work, assuming one was available, but a boring head would be an acceptable approach. For that matter, so would the hole saw mentioned, assuming spindle speed wasn't an issue. This could be done on a larger drill press, but not as easily as with a mill.

The fixture in question would require bushings for the enlarged holes, so holding size would be a good idea.

Given the fact that there's a number of pieces, one hole in each part would be machined, then a second operation for all parts, then a third.

H

[Mr Ron]

Would a step drill work?

[NP317]

I find the silence of the O.P. to be interesting.
~RN

[liveaboard]

I find the silence of the O.P. to be interesting.
~RN

Yeah, I also had an idea but can't be bothered to type it out.

[John Hasler]

Harold writes:
Even with a rigid hone, progress would be dreadfully slow.

Without the right tools, that's the way it's going to be.

Looking closely at the photo I see a bit of a lip on the holes. He may not need to ream any deeper than 6 mm or so. The reamer I linked to might work, depending on how deep the hole actually is. If not he could grind down the reamer.

[Steggy]

What happened to the OP? You'd think he/she would be periodically getting into the "conversation."

[lothian]

Thanks for the replies and offers of suggestions to my dilemma.

Sooo...
It turns out my problem was incorrect spindle speed. I took the advice to look up the cutter diameter and set drill RPM accordingly. I lowered the drill press speed and gave it another try using the carbide cutter. The bit cut right through the fitting with comparative ease. I feel like an imbecile for not considering so simple a solution sooner. It just never occurred to me. Yeesh.