A "Different" Different Opposed Piston Engine

[Tennessee Whiskey]

I'm with the rest on the great info on the boring bar, laps, and paste. Now, if I can borrow your credit card that will make it perfect . I've been watching and enjoying every bit of it. Can't wait for the first sputter, pop, and run

Whiskey

[GailinNM]

Busy weekend, but I did manage to make up the simple parts of the base and bearing mounts. They are just shaped plates with holes in the the right places I hope.  Changes from Brian's that you can see are:
*Reduced the number of mounting holes for the uprights.
*Increased the length and width of the base so I could radius the corners and edges.
*Changed bearing holes to use flanged ball bearings.  You can see the recesses for the flange.
*Not visible is the increased base thickness because I had a piece of stock about the right size.
Gail in NM

[steamer]

Looks good Gail.  What's next on this beasty?

Dave

[Jo]

Looks like you are using steel for this build , much nicer material to work in. 

Jo

[b.lindsey]

Nice to see this update Gail and thanks for all the links and the write up on boring and honing. MSC can be a good source for many of us here in the US, but as you say, Enco, Amazon, and HF can save some money on less critical items. I am enjoying the build!

Bill

[steamer]

Thanks for following along.  Nothing like interest to speed things along.

I should have provided more details about my bore finishing operations so will do so now.

For boring I used a solid carbide micrograin boring bar. Several people make them and since I have been using the same one for 15 years or so I am not sure whose I am using.  But the specs are 0.320 inch minimum bore with 1.25 maximum depth and a 0.365 inch shank.  It is the equivalent of this one but a lot less money back when I bought it.

http://www.mscdirect.com/browse/Turning-Boring/Boring-Bars-Grooving-Tools/Boring-Bars?navid=12105888+4288237782+4288232280+4288237789+4288232279+4288215366

The Flexhone is this one.  They can generally be had on Ebay for about 1/2 as much money.

http://www.mscdirect.com/browse/?navid=12100209+4288246421+4288168592+4288225324

The URL that Roger gave for ACRO laps is a good one, but note that their price list is 7 years old and prices have about doubled since then. They also make metric sizes which are not generally cataloged by USA suppliers but they do sell direct. If you are going to be using more than one grit of abrasive for lapping buy an extra barrel for each grit.  After using itl, put it in a plastic bag with a label and always use it with that grit.  Never mix grits on the same barrel and you can not tell by looking at it which grit it was used with. Here is a link to the one I used on the MSC website.

http://www.mscdirect.com/browse/Abrasives/Laps-Hones/Through-Hole-Laps?navid=12100079+4288090273

For abrasives I use diamond compound. Don't be put off by the seeming small amount in a 6 gram tube.  I have used about 2 grams over the last 10-15 years.  It does not take much. Since I bought mine Shars has started carrying it at about 1/4 the price of other suppliers.  I have not tried the material from Shars, but it should work OK.  Here are links to both Shars and Enco for suitable compounds.

http://www.shars.com/products/view/5291/USBS_9_Diamond_Polishing_Compound

http://www.use-enco.com/CGI/INSRIT?PMAKA=619-0158&PMPXNO=16717886&PARTPG=INLMK32

Very important is cleaning the bore after lapping.  It does not make any difference if you are using aluminum oxide , silicon carbide or diamond compounds you must SCRUB the bore before ever inserting any hard into the bore. No pistons, plug gages or anything hard.  If you do residual abrasive can be forced into the bore and will never come out with cleaning.  I use test tube brushes, dish washing detergent and hot water.  Nylon tube brushes are available at many stores but Amazon has them as well as Harbour Freight. The Harbour Freight assortment only has one or two useful ones for me, but if lyou are visiting their store they are cheap enough to pick up a package.  Amazon's has a variety and if you are ordering other things and qualify for free freight they are cheap enough.

http://www.harborfreight.com/9-piece-tube-pipe-nylon-brush-set-90631.html

http://www.amazon.com/Test-Tube-Brush-Pack-10/dp/B003LRVR4W/ref=sr_1_8?ie=UTF8&qid=1390050562&sr=8-8&keywords=tube+brush

Some general information on what I am trying to accomplish which is plateau honing.  The Flexhone leaves a relatively rough finish with grooves on the order of .0005 deep.  When lapping this only the tops (plateau) is removed leaving these grooves with very smooth tops.  These grooves act as oil retaining areas and reduces the sliding area reducing friction while still maintaining a very good seal.  For more information do a search on "Plateau honing".  It is being used quite a bit on high performance automotive engines. I don't know if l am accomplishing this or now but it makes a good story. I do know that this procedure works for me.

Any questions -- just ask. I may not have the answers but you can ask and others may chime in with the answers.

Gail in NM

Thanks Gail!

Wot Bill said!     I missed this, but glad I found it.    I will get the brushes, I used many old rags when I did the barrel on my SB  And it seems to be doing fine so I guess I got it clean. 

the other one is Gun cleaning brushes...usually bronze wire.    May work well.

Dave

[b.lindsey]

Gail...just a quick question...is the green diamond compound the only one you use or do you keep any other grades (either coarser or finer) on hand as well?  Shars prices are significantly lower than Enco, I am wondering if the quality is the same or perhaps carries  a lesser concentration of diamond dust.

Bill

[GailinNM]

Thanks for looking in.
Dave: Next up will be bits and pieces. I am waiting on a M6x0.5 tap that I will be using to mount the valve cages to finish up the cylinder mount.  I will probably do the flywheel and spark plug.  Flywheel will be a stock design that I use and the spark plug will just be a short reach version of the one I used on my original opposed piston engine and the H-N-M tiny.

Jo:  No, the base and uprights are aluminum.  My color vision was always poor and now the AMD has robbed me of almost of it. So, I don't do any color correction on my photos. I just let the camera decide and the viewers guess. It's going to be a lot closer than what I can do. There are light colors, dark colors and every thing else.  I will try putting a reference white card in the photo outside the crop and have the computer balance on that before cropping and see if that helps any.

Bill: I keep three grades of diamond on hand.  They are 30 micron (22-36 red) that I use if I have more than a couple of "tenths" (0.0001 inch) to remove, 10 micron (8-12 green) that l mostly use for finishing, and  6 micron (4-8 orange) that I use for a final polish sometimes.  l did make a quick pass with the 6 micron on these cylinders but, while nice, it is not really necessary.  The compounds come in 3 grades according to their concentration of diamond.  Light, medium and heavy.  Light is fine for our use. My 30 micron is light and works fine. The other two are medium because that was easily available at the time. I think that the Shars' is probably light and I would not be afraid to use it.

You don't use much of it.  When it starts getting sticky on the lap I just add a little light oil on the lap and keep going. After about 3 or so times of adding oil I add a little more compound.

Since there has been quite a bit of interest in the lapping process IL tried to shoot a photo of the lapped surface through the cutout in the bottom of the cylinder.  My old USB microscope could not get in close enough to really show it so I shop a macro with my camera.  It does not show what I really wanted to show but if you look close enough you can see some of what I wanted to show.  In the lower left corner of the photo you can see a few of the diagonal scratches left by the Flexhone.  They, and many more, show up well on my bench microscope with adjustable lighting but I don't have any photo capabilities with it.  For scale, the hole in the photo is the 0.094 that the oil cup mounts in.
Gail in NM

[b.lindsey]

Many thanks for the additional info Gail!!

Bill

[Roger B]

This is the Acro price list for 2013 that they sent to me.

 

[GailinNM]

Thanks for the updated price list Roger.

While deciding what to do next I stuck some of the bits together to get more of a feel of the engine.
The spark plug is not the right plug and is too long so probably I will make the right plug next.
Gail in NM

[Brian Rupnow]

Gail--You are doing a wonderful job!!! I'm going to have a heart attack if you get yours finished and running before I do!!! I've spent this morning working on the newest "Chuck Fellows carburetor" for my engine.--Brian

[Roger B]

Excellent job  and very good descriptions of the techniques you use 

[Don1966]

I want one..........Man that looks good Gail and I am certainly getting some great information here. You certainly have been moving along guick. Just keep it coming. 
 
Don

[philjoe5]

Seems like you will have a runner before me Gail, but I think I'm close behind.  I'm enjoying your build and have learned a lot

Cheers,
Phil