Author Topic: A new attempt at making piston rings  (Read 10429 times)

Offline Art K

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Re: A new attempt at making piston rings
« Reply #165 on: June 08, 2021, 01:57:14 AM »
Brian,
That sounds like a good deal!
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #166 on: June 08, 2021, 03:54:29 PM »
That would be 1100 degrees F with a 3 hour soak time. I have tons of input on this one, and everybody is recommending something different. This is why I bought a heat treat oven. I am hoping that I can make working rings, and that I can set up a standard and repeatable process for doing so.

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #167 on: June 08, 2021, 04:14:15 PM »
A local milling machine cutter sharpening service is currently making this tool for me to groove aluminum pistons for 0.038" wide rings. Actually, his price for a tool as shown here was $60, but a lot of that must have been set-up, because he also quoted me on a double ended tool for 75$. I ordered the double ended tool and will have it sometime this week.

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #168 on: June 08, 2021, 09:44:03 PM »
I called the toolmaker this afternoon about the cutting tool he is making me and asked about side clearance.  He was out, but I left a message. He emailed me back and this is what he had to say.

"Hi Brian

Sorry I missed your call. I was driving.
I intend to put side clearance on the tool. Probably only 2-3 degrees per side. I would put more because itís aluminum but itís pretty small. I will also make the tool narrower at the base. Only by .001/.002 but it will give you a cleaner cut. Both clearances will stop the aluminum from smearing and give you a better cutting action. I should have them ready tomorrow and Iíll let you know. Thanks"


 Okay--I never claimed to be a tool designer.  This guy is good. He has sharpened cutters for me before, and I was impressed by his background and knowledge.

Offline gbritnell

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Re: A new attempt at making piston rings
« Reply #169 on: June 08, 2021, 09:56:34 PM »
Brian, I hate to say this because of all the contributions you have made and the unique engines you have built but sharpening a high speed lathe tool is kind of like machining 101. I use HS lathe tools almost exclusively on both my 6 and 11 inch lathes and must have at least 40 styles in both 1/4 and 3/8 . Making a necking tool like you show is about a 10 minute job. Just saying!
gbritnell
Talent unshared is talent wasted.

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #170 on: June 08, 2021, 10:49:20 PM »
George---I have no problem grinding an HSS cutting tool. I do however, have great problems with grinding an HSS tool with any kind of dimensional accuracy. I don't have a Quorn, nor anything like it to let me control depth of cut or angle of cut. If I thought I could grind this tool myself, I certainly would have, and saved $75.00.----Brian

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #171 on: June 09, 2021, 05:30:26 PM »
Yesterday I ordered a "fine India stone" from Norton.  They don't cost much, and I don't have a lot in the way of sharpening stones.  I bought a 1" x 4" stone. I have one big double sided stone that I inherited from my dad, and it works fine for sharpening jackknives and kitchen cutlery but isn't something you would use on material chucked in a lathe. Trimble recommends a "Fine India stone" as part of his write up on ring making.

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #172 on: June 10, 2021, 06:07:34 PM »
Today I picked up my 1 mm (0.039"0 lathe tool from Can-cut, a local sharpening service. Yes, it does have a bit of side relief on it. He made it using a surface grinder. ---Yes, I paid $75 for it, but this is still only about 1/2 of what I would pay for a carbide and toolholder out of USA.  Next step will be to machine a holder for this tool and see exactly what width of cut it actually makes in a 1" diameter piece of aluminum round stock.----And yes, I agree with the sentiment "More money than brains".

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #173 on: June 10, 2021, 08:44:54 PM »
Something very fishy is going on, and I don't know what. My new tool is setting at exactly the correct height (centerline of spindle), perfectly square to the long axis of the lathe, and the tool is ground perfectly square across the end. I made three plunge cuts, using the cross slide to advance the tool into the cut, with lots of wd40 as lubricant. My new tool is set up with very little unsupported "stick out". Then I cut the aluminum round blank on my bandsaw to expose a cross-section of the cut. All of these cuts look crooked to me. I don't think there is any way that a ring can seal against either side of the plunge cut.  My cross slide is set at 90 degrees to the long axis of the lathe.  Does anyone have an explanation of what may be going on here?

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #174 on: June 10, 2021, 08:54:46 PM »
Cancel that last question.--Investigation shows that tool was setting crooked in holder. I will make a better tool holder and try this again.

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #175 on: June 10, 2021, 09:54:10 PM »
Okay---Proper tool holder gives perfect grooves. The grooves measure 0.040" wide with my Vernier caliper, so I'd say it's good. The grooves appear at a proper 90 degrees to long axis of part. I'm happy with the new tool.


Offline Art K

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Re: A new attempt at making piston rings
« Reply #176 on: June 11, 2021, 01:58:21 AM »
Brian,
That's a good catch on that crooked cutter, glad that you tried a sample cut before ruining a piston.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #177 on: June 11, 2021, 04:46:01 PM »
I just got a quote from Caliber Industrial Supply in Ontario for one Thin-bit holder and two very narrow carbide tips (which they sell in minimum quantities of 10) for a grand total of $429.00 Canadian funds. This makes the $75 I just paid for a double ended HSS tool look pretty darned cheap by comparison.---Brian

Offline propforward

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Re: A new attempt at making piston rings
« Reply #178 on: June 11, 2021, 05:38:44 PM »
You can definitely get a holder and carbide inserts for less than that $429 - BUT certainly not for $75 without going to questionable import quality, and you can easily keep honing that HSS tool for a long while. Should last plenty long.
Stuart

Offline Brian Rupnow

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Re: A new attempt at making piston rings
« Reply #179 on: June 12, 2021, 08:56:19 PM »
This is a video I made today, 11-june-2021 of my vertical i.c. engine 2021. I have been trying to make a set of  cast iron rings for the piston, and as part of that I built a new cylinder and new piston to accept cast iron rings, but ultimately I was not successful. Finally I decided that I should put this engine back together, so I enlarged the top ring groove to .093" wide x 0.058" deep and put a Viton ring on it. This engine can now go up on the shelf with all of my other engines. I am still after cast iron rings that actually work, but will be trying them out on a different engine that is a lot simpler to take apart and access the piston.----Brian