Reaming Cast Steel Fittings without a Mill

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lothian
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Reaming Cast Steel Fittings without a Mill

Post by lothian » Fri Jun 28, 2019 9:07 am

I have dilemma.
I need to enlarge the opening in a bunch of cast steel fittings by less than a millimeter. I do not own a mill, and I lack acquaintances with such. So I have to make due with my drill press and whatever seemingly suitable cutting tool I can source. This setup isn't working. I'm soliciting practical suggestions/recommendations.

Here's an image of a typical (SteelTek brand) fitting.
fitting.jpg
I need to enlarge the fitting's 29.2mm openings to 30mm (I have a LOT of these to do). I presumed removing this smidgen of material would be a breeze. Yet no HSS bit I've used (shown below in order of attempt) can cut the steel effectively under a deluge of cutting oil.
bit11.jpg
bit22.jpg
bit33.jpg
I haven't tried a chucking reamer (below) simply due to cost: These things are hurty-expensive at the diameter I need.
bit44.jpg
I suspect the cutters I've tried are not exclusively the problem. I believe my drill press is under-powered for this job--it spins down on contact and stalls constantly. Clearly I underestimated the tensile strength of cast steel fittings, and I overestimated the robustness of my shop tool to do the job. But I need to get this done.

Any suggestions?

John Hasler
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Re: Reaming Cast Steel Fittings without a Mill

Post by John Hasler » Fri Jun 28, 2019 9:36 am

Try a brake cylinder hone.

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NP317
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Re: Reaming Cast Steel Fittings without a Mill

Post by NP317 » Fri Jun 28, 2019 10:56 am

Holding the part rigidly is a requirement, regardless what cutting tool is used. A drill press is unlikely to provide that support.
And post your location in case someone on this board is close enough to assist you.
~RN

johnfreese
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Re: Reaming Cast Steel Fittings without a Mill

Post by johnfreese » Fri Jun 28, 2019 12:45 pm

The hoe cutters should do well provided you can pilot them on the existing bore. As NP317 sail rigid support is essential.

Harold_V
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Re: Reaming Cast Steel Fittings without a Mill

Post by Harold_V » Fri Jun 28, 2019 4:04 pm

John Hasler wrote:
Fri Jun 28, 2019 9:36 am
Try a brake cylinder hone.
Not a good idea. Honing is a slow process, not really intended for stock removal. And, unless a rigid type hone is employed, it will just ruin the parts (I'm making reference to the common spring loaded three stone hone).

I suspect that if the hole saw with carbide inserts was selected, it would serve adequately, but in order for the saw to perform properly a rigid setup would be required, with the part held in some kind of holding/locating device, and the spindle slowed to increase torque. This job really screams for a mill, or a mill/drill, where a boring head could be used.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

whateg0
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Re: Reaming Cast Steel Fittings without a Mill

Post by whateg0 » Fri Jun 28, 2019 4:13 pm

I'm not sure how you would use a holesaw or an annular cutter on something with an existing hole like that. What do you use for a pilot?

In my shop, I would probably use the lathe, but that's not necessarily the fastest setup. What rpm are you running your tools? At almost an inch-and-a-quarter, any HSS tool needs to spin pretty slow, around 250 rpm, if the math in my head is right. I would expect a HSS reamer to suffer the same issues as a HSS drill, though it would likely start smoother.

If you can keep it from spinning, I would think a drill press at a slow enough speed would do the job as it has an existing hole to follow.

Dave

whateg0
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Re: Reaming Cast Steel Fittings without a Mill

Post by whateg0 » Fri Jun 28, 2019 4:16 pm

lothian wrote:
Fri Jun 28, 2019 9:07 am
...I need to enlarge the fitting's 29.2mm openings to 30mm (I have a LOT of these to do). I presumed removing this smidgen of material would be a breeze. Yet no HSS bit I've used (shown below in order of attempt) can cut the steel effectively under a deluge of cutting oil.
...
How many is "a lot"? 20? 500? The quantity to be done would factor into how extensive any fixturing would be for me.

As somebody else mentioned, putting a location might open up some possibilities of either assistance or equipment.

Dave

John Hasler
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Re: Reaming Cast Steel Fittings without a Mill

Post by John Hasler » Fri Jun 28, 2019 4:46 pm

Harold_V wrote:
Fri Jun 28, 2019 4:04 pm
John Hasler wrote:
Fri Jun 28, 2019 9:36 am
Try a brake cylinder hone.
Not a good idea. Honing is a slow process, not really intended for stock removal. And, unless a rigid type hone is employed, it will just ruin the parts (I'm making reference to the common spring loaded three stone hone).

I suspect that if the hole saw with carbide inserts was selected, it would serve adequately, but in order for the saw to perform properly a rigid setup would be required, with the part held in some kind of holding/locating device, and the spindle slowed to increase torque. This job really screams for a mill, or a mill/drill, where a boring head could be used.

H
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

spro
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Re: Reaming Cast Steel Fittings without a Mill

Post by spro » Fri Jun 28, 2019 4:50 pm

I looked up these structural steel corner braces. There are things I don't know since I don't have one to see inside. I don't know if the central tube hole goes through or stops. If it goes deep enough, a pilot hole could be drilled at center axis of well fitting tube. The hole is aligned by the clamp screw to either the two other tube holes. The pilot hole would be the same diameter as the pilot drill but it would be drill blank/ smooth rod. You would need two lengths. The longer of course, for starting and aligning the outside. That would be replaced by the shorter one as it is deep cut.
These two look to be bored wider inside, so you are dealing with two internal lands which need bored or reamed, of each. It is such a small area that I think it could be done with some of the tools that you already have. Pilot support and secure attachment,

jcfx
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Re: Reaming Cast Steel Fittings without a Mill

Post by jcfx » Fri Jun 28, 2019 4:57 pm

How accurate does the hole have to be ?
Not an elegant solution but a drum sander in drill press would probably take down the .8mm
that you need.
I was going suggest a cylinder ridge reamer but they don't seem to come any smaller than 2" dia.

spro
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Re: Reaming Cast Steel Fittings without a Mill

Post by spro » Fri Jun 28, 2019 5:27 pm

Well, the OP said it. It is a reaming but not by the older adjustable reamers I have. The retaining nut at the end sticks out too far. I think I need to look at "blind hole adjustable reamers".

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Bill Shields
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Re: Reaming Cast Steel Fittings without a Mill

Post by Bill Shields » Fri Jun 28, 2019 7:24 pm

instead of opening the hole...can you turn DOWN the pipes????
Too many things going on to bother listing them.

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