Mery 6-stroke kit.

[PhilL]

Hello Jack3M!!
Great job on your Mery. Mine is the one you refered to in the beginning, http://www.teqknow.com/Shop/Mery.html. I didn't see this thread until I got todays digest in email.
There are many places where you need to plan several steps ahead but it looks like you're doing perfectly with that.
FYI: I think I painted mine 4 times, never liking the results I was getting. I haven't done powder coat on my engines but I'm watching with great interest.
Did you get a copy of the Mery Newsletters? They have some really good info for the build and runs. Also history of the process the group used building the model.

Keep up the great work!

PhilL

 

[Jack3M]

Hi Phil,
Thanks for the compliment, unsure if folks think I am a fool or know what I am doing. In reality, I am neither. I am starting to research ignition system, links appreciated (And knowledge).

My climate is so wet I need to get rustables covered as soon as possible, so as soon as I get the part where I won't mess it up in vices or can use wood to prevent chipping. Powder coat is great because you can use harsh cleaners like carb cleaner and it won't touch it. It is only expensive to get started. You need a gun better than HF sells, compressor, toaster oven or better (dedicated) and the powders. Powders from Prismatic Powders run 10-20 per pound. A pound goes a very long way. Mixing and matching solids and transparents is cool. So once set up, it is way cheaper than paint to put a thick coat on anything that can tolerate 400 degrees for a half hour. The Mery is a solid, transparent, and finally a special clear for the solid.

I have been through your site over and over, the best one I know of out there, adapting to my smaller mill.
I am not aware of the Mery Newsletters?
Jack

 

[Jack3M]

Measured out where the grooves for the woodruff keys go and cut them. May, but probably not get to soldering it a ll up today.

 

[Jack3M]

Well wife (who is on vacation this week) went off on a shopping trip so it got soldered together.

Used a pair of spacers to maintain the space between each lug and the woodruff key slot needs to be 90 degrees to the rod end.

Then of course cleanup the part which is still in process.

 

[Jack3M]

Well crud, didn't expect it to be out of line and was off .001, which when I turned it on the lathe to clean off the solder, it took metal off the shaft and screwed up my tolerance. Had to go get more drill rod. Next time I solder from the inside as that gets cut and gound off. The rod end is okay, and will try to run another shaft thru with that still attached, see just how true is still is or isn't? Grrrr.

 

[PhilL]

You don’t want to turn it from bar stock? All that heat is always going to make stuff move.
Did you get my email?

 

[Jack3M]

No I did not, and tho not done, it is straight. Fits well, turns easily. Still cleaning up and polishing to go.

 

[Jack3M]

Hope all is well with everyone. Crank finished, cleaned up and powder coated. Did the piston rings today too.
Crank turns nicely by hand, freely, getting about one full turn with a minor 'flip' on the shaft. Now, I am going to put the flywheel and the belt pulley on the same shaft which puts the long side to the right instead of left as shown in some of the plan steps. AND the keyway leads the crank by 90 degrees so it makes a difference when you assemble. Rotation looking from right side into the engine is CCW

 

[Jack3M]

POWDER COAT IS NOT IMPERVIOUS TO CARB CLEANER/LACQUER THINNER. Oops

 

[Jack3M]

Not sure how to do the flywheel at this point. Researching ways to do it on the mill as it is too big for the lathe(10.5). Several ideas for mill are feasible, just not sure which is going to work or not. Cannot use a 3 or 4 jaw chuck, none fit the flywheel that will fit on the rotary table. So thinking time, research time, trials time. Of course I could mount it to the shaft of the mill after there is a true center hole. Getting this dialed in is difficult, I can already tell there is a difference in spoke to table height for individual spokes, not much, thousandths, but enough to make a difference . Don't have any pals with larger lathe. Local shops are weeks out and they really don't want piecemeal. Just need to find the way.

 

[Jack3M]

Not having success with this. Let me back up, 5" rotory table. Centered to spindle of mill and DRO zeroed for later. I have a dial indicator in the mill spindle for the center hub of the flywheel. I have a dial indicator on the outer ring on the "up" side. Now we all know that the flywheel isn't perfect.

I can get the center hub to .0025 +/-. But the outer ring will not come into play, it is at a minimum changing height to table by .040+ . I am not able to tell if the flywheel just has a low spot or the whole thing is off to one side.

Initially I was using 1/2" scrap blocks to hold the wheel up off the table as there are protrusions that must stay. So turned down a piece of 4"pipe to 1/2" and used that as a trial. It miked out to .0005 so it was really close. Same problem. It also moves as I tighten down the flywheel so just trying to get solid without deforming. That does not really seem to effect the side of the wheel in question and the drop off is very quick and also the return to the high is very quick, a good 20 thou at either end.

I need suggestions, advice, and ideas please.

 

[PhilL]

I’m trying to picture this. What are you sitting the flywheel on? The spokes? And the height of the rim is varying .02? The finished thickness should have ample to get that cleaned up.
Maybe clamp the flywheel to the mill table resting on the rim. Then take very lite cuts to get reference points on the spokes. Then use them to rest on your 4” pipe. The rim will be true then. Once it’s all done, you can take a file and blend the flats on the spokes and they go away.
Then again, I may have totally misunderstood your problem.
Maybe a picture?

 

[MrMetric]

I'm struggling with the same thing... If Jack had a lathe of sufficient swing, he would bore the shaft and then true up the wheel, right? I think he is having problems coming up with a clamping arrangement so he can hold the wheel to a rotary table. OK... the spokes will vary and there will be warpage in the wheel. I understand that. But there would be no perfect solution to that. You'd have to (effectively) clamp the wheel down such that it would be concentric on the rotary table (i.e the bore). At that point, he'd need to shim the different parts of the wheel so that he could mill them. There would be no formula for that. It would be all trial and error.... But he is right that he can't deflect the wheel when clamping it. The wheel would simple spring back when it was releasedd.

I too must be missing something. I'm quite certain that Jack is more adept than I, frankly!

 

[Jack3M]

Unfortunately I am not good at describing something like this. Though, I think I have it.
The part is clamped to the rotory table. It is supported on the spokes by the 4" diameter spacer.
The center hub (best I can get with bumps and such on the hub...tho filed) is .0025 +/- so a total of .005. I find this acceptable as a start.
The outer ring (side) is where I have this huge discrepancy. After literally hours of checking and trying I figured out it is a low spot between two spokes on one side only. Measuring from the main table to the bottom side of the outer flywheel there is only a .002 difference in a full circle. Therefore it is a low spot on the flywheel.
Currently am waiting for an ER40 chuck so I am sure the hole in the center is perfect. I do not plan on milling either side of the wheel, only the center hub and the very outer diameter of the flywheel.

Now another problem I am having is the cylinder assembly got messed up and had to recoat with the color, only now I am getting burst bubbles that are not flattening out. Had called Prismatic Powders but with holiday no good response yet. This is 3 times same problem.

 

[Jack3M]

Forgot the photo or it didn't upload apparently.

 

[MrMetric]

Though perhaps not germane to your particular issue at hand, it strikes me that one of the fundamental problems with clamping here is providing support while not flexing the part. You can do a lot of trial and error shim work or possibly go down a casting approach. Cerrobend, Roto, or even epoxy (with a release compound) may be able to fill the gaps between a steel/aluminum base and the part. Although those may be soft, with enough surface area, it might not matter much.

I'm just spit balling here; I've not tried this type of technique before because I haven't really run into the problem (novice engine maker), but using sand bags and such in metal forming isn't anything new. This is kind of a variation of the same thing.

What this would *not* do is address reference problems. It would only enhance the ability to hold the wheel to the rotary table.... Anyhow, just a thought.

 

[Jack3M]

Yes, thank you for your thoughts. By using the 4" diameter pipe piece, I am supporting under the spokes evenly and clamping as close to as perfectly over the pipe section. Thusly, I don't get any change if I push on the outer wheel at one spoke or another. ..

Still looking at it, thinking on what could be wrong and meanwhile working on the belt pulley between attempts to get the powdercoat to work on this one part, 3 recoats now with teensy bubbles at one end in a "show" spot.

 

[MrMetric]

OK. For some reason, I got it into my head that part of the problem was that you were having a difficult time clamping the wheel down due, in part, to deflection. Don't ask me where I got that.

As for the powder coating... I've never used that form of "painting" so I don't think I can add to your comments there, except for one thing... It seems to me that the bubble could be caused by impurities that result in contamination?

 

[Jack3M]

These tiny bubbles show in approximately the same area. Just not sure. At this point waiting for Prismatic Powders engineer to get back to me, customer support went to them because they didn't know what to do or why.

As I look at the drawings for the flywheel, I may have to do some milling for appearance/detail/etc. It is almost a quarter inch over thickness in width so there is plenty and hoping my crankshaft modification will compensate.

 

[Jack3M]

The belt pulley polished out well

and started on the flywheel