Author Topic: A new attempt at making piston rings  (Read 20061 times)

Offline Brian Rupnow

  • Full Member
  • *****
  • Posts: 7575
  • Barrie, Ontario Canada
Re: A new attempt at making piston rings
« Reply #90 on: May 11, 2021, 03:52:52 PM »
I didn't "true the wheel" with a diamond dresser. I did buy a diamond dresser to true the wheel, but didn't use it this time. (I still have to cobble something up to hold the diamond dresser while I do that, just haven't got that far yet.)  Keep in mind, I haven't done this before, and mostly I wanted to try it out for "process". The rings were extra rings that I had made, but they weren't that great. I don't expect to actually use these rings, but I had to try the new fixture and grinder out for "process".  There are a couple of things I will change, but they mostly relate to the tooling. I find that when using my 3 jaw lathe chuck that if I take anything out of the chuck, it is almost impossible to put it back in the chuck and not have the outboard end wobbling.  I am going to investigate using a tailstock support for the free end to make it run true, but I have to investigate and see if I have room to do that.

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 6133
  • Switzerland
Re: A new attempt at making piston rings
« Reply #91 on: May 11, 2021, 04:55:46 PM »
I have never been able to reuse a truing fixture in the 3 jaw chuck even by marking where the jaws were. Using the 4 jaw independent is better but for the price of a dog end of steel I just make a new mandrel each time. The sizing ring is always ok (unless you change the bore size  :facepalm: )
Best regards

Roger

Offline Brian Rupnow

  • Full Member
  • *****
  • Posts: 7575
  • Barrie, Ontario Canada
Re: A new attempt at making piston rings
« Reply #92 on: May 11, 2021, 06:24:39 PM »
A part of this goose-chase is going to be building an independent support for the diamond wheel dresser. I will have to build this as an independent stand alone item, because I have nothin else that will work to hold it.

Offline jeff l

  • Full Member
  • ****
  • Posts: 234
Re: A new attempt at making piston rings
« Reply #93 on: May 11, 2021, 06:28:19 PM »
Couldn't you make a clamp that attaches to the tailstock barrel ?

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 6133
  • Switzerland
Re: A new attempt at making piston rings
« Reply #94 on: May 11, 2021, 06:36:04 PM »
Brian, you seem to be going way beyond what anyone else has done  :headscratch: If your rings don't seal I can only think that as I have said your bore isn't round or that the size isn't what you think it is. I don't have any internal measuring instruments other than a dial calliper (which is worst on internal dimensions  ::) ) so I always make plug gauges.
Best regards

Roger

Offline Brian Rupnow

  • Full Member
  • *****
  • Posts: 7575
  • Barrie, Ontario Canada
Re: A new attempt at making piston rings
« Reply #95 on: May 11, 2021, 07:04:16 PM »
Roger---I've been thinking about the reusability of a truing fixture. I just measured my lathe, and it's about 18" from the end of the chuck jaws back to the far end of the spindle tube. My spindle tube is 1.5" inside diameter.  The truing fixture is only 1.125" at it's largest diameter. I think that if I made a bushing to keep the truing fixture centered at the back end of the spindle tube, and match marked it to one of the three chuck jaws, that it should be very repeatable every time I use it. I am trying to come up with a procedure and tooling that is reusable and will give me the same results every time I use it.

Offline Brian Rupnow

  • Full Member
  • *****
  • Posts: 7575
  • Barrie, Ontario Canada
Re: A new attempt at making piston rings
« Reply #96 on: May 12, 2021, 09:26:23 PM »
And there it is---My version of "Diamonds are forever". This stand holds the diamond for truing the grinders abrasive wheel. it doesn't look like much, but there's a days work in that thing. My bandsaw really, really doesn't like cutting 1 1/2" thick plate. It's so slow that I feel like I'm going to start growing moss while I wait for it to finish a cut. I still have to make the plate that goes across under the lathe ways and the piece of 1/2" all thread rod that comes up thru the vertical plate and gets a nut on it to hold everything stable. Those of you who are sharp of eye will see that the design changed a little bit from the model I posted yesterday.--Two 1/2" threaded rods are overkill.

Offline swarfjunky

  • Full Member
  • ****
  • Posts: 6
Re: A new attempt at making piston rings
« Reply #97 on: May 13, 2021, 01:16:52 AM »
Brian, I'm one of the many quiet ones on this forum following this and other build threads with lots of interest. I purchased your plans for this engine and have the crankcase and cylinder partially done at this time and looking forward to the day I fire it up.

Having a few years experience operating a cylindrical grinder in the past I would like to make a suggestion on the positioning of your diamond dresser. It's recommended that the dresser be tilted down (in the direction of wheel rotation) 10 to 15 degrees and periodically rotated 1/8 turn to maintain a sharp point. This practice creates facets so to speak. Positioning the dresser horizontally eventually dulls the diamond by creating a flat spot on the face of the diamond. For best results it is also important that the dresser contact the wheel at the point where the circumference of the work touches the circumference of the wheel, referred to as the work/wheel contact. Hope this information is useful to you.

Am looking forward to your success in this ring making process.

Rog

Offline Brian Rupnow

  • Full Member
  • *****
  • Posts: 7575
  • Barrie, Ontario Canada
Re: A new attempt at making piston rings
« Reply #98 on: May 13, 2021, 04:12:55 PM »
The diamond support tower is finished. It all goes together nicely and locks securely in place. Now I am getting posts that say the diamond support shaft should be tilted down 15 degrees. That is not a major problem, just a bit more work. Are we agreed that the diamond itself should still be on the same centerline as the grinder shaft?

Offline swarfjunky

  • Full Member
  • ****
  • Posts: 6
Re: A new attempt at making piston rings
« Reply #99 on: May 13, 2021, 04:56:55 PM »
Are we agreed that the diamond itself should still be on the same centerline as the grinder shaft?

Yes, the optimum set-up would be the grinder shaft centerline, lathe spindle centerline and diamond should all be on the same plane.

Rog

Offline Brian Rupnow

  • Full Member
  • *****
  • Posts: 7575
  • Barrie, Ontario Canada
Re: A new attempt at making piston rings
« Reply #100 on: May 13, 2021, 09:11:33 PM »
One more time with feeling---This time the diamond support is set at an angle of 15 degrees with the center of the diamond on centerline of grinder spindle and chuck all in the horizontal plane. It isn't quite as pretty as the first time around, but form follows function.


Offline Laurentic

  • Full Member
  • ****
  • Posts: 310
  • Nr Yeovil, Somerset, England
Re: A new attempt at making piston rings
« Reply #101 on: May 13, 2021, 09:49:18 PM »
I thought it was suposed to be tilted down 15 degrees - Brian yours look like it is tilted up 15 degrees!

Offline Brian Rupnow

  • Full Member
  • *****
  • Posts: 7575
  • Barrie, Ontario Canada
Re: A new attempt at making piston rings
« Reply #102 on: May 13, 2021, 10:44:19 PM »
It is tilted up 15 degrees. If it was tilted down, the wheel would pull the diamond out of it's holder. Ahhhh Jeez---Now I'm being told that the diamond tool should be 15 degrees opposite to what I made it.---that it should be angled down at the front where it contacts the wheel.
« Last Edit: May 13, 2021, 11:20:33 PM by Brian Rupnow »

Offline john mills

  • Full Member
  • ****
  • Posts: 417
Re: A new attempt at making piston rings
« Reply #103 on: May 14, 2021, 01:34:13 AM »
referring to my grinding book mc phersons  they where an austrailan manufactor and agent of machine tools
years ago when things wear made hear  it says it is good practice set the diamond at or just below centre at an angle of about 15 degrees  the drawing shows it angled downwards at 10 to 15 degrees.  the diamond should be rotated after every few dressings  which has the effect of keeping the diamond sharp. the company has long gone
but i have had the book from when i was an apprentice  .i know that work after mar than 50 years in machine shops .   John

Offline Brian Rupnow

  • Full Member
  • *****
  • Posts: 7575
  • Barrie, Ontario Canada
Re: A new attempt at making piston rings
« Reply #104 on: May 14, 2021, 01:54:59 AM »
Third times a charm!!!--We're setting at 10 degrees angle and diamond is at or just below spindle centerline. And the moral to this story is Research-Research-Research. I spent two minutes on Google and found all kinds of information about what I am doing here, even drawings. Luckily, I didn't have to make any new fixtures---Just relocated the hole for the shaft which holds the diamond. Anything from 5 degrees to 15 degrees is suitable, so I'm good with this. Arrrrggghhh!!--Let that be a lesson to me.


 

SimplePortal 2.3.5 © 2008-2012, SimplePortal