Mery 6-stroke kit.

[Jack3M]

Okay, after analysis; the depth I cut was 0.070, determined by the calcs above. That was one extreme, the min was 0.067. Will that .003" be enough? I will admit my gibs need tightened, which I can do now that the thing is over. Also, I did it in 3 different sittings, so I could have goofed somehow. Obviously the teeth are cut too deep, no flat on the top. Also, at one point early on....had to remove the cutter and get relief, and used the previous cuts to align the cutter to same tooth. Then started back over in the same place as originally, the alignment was not off at that point, but that was not a good thing to do regardless, at that point I had no other choice. The relief was necessary because of the small diameter material chosen for the tool 0.5". Considering making a new one from some 1.25" tool steel I have on hand. Hate to waste it on a 32DP 14.5. Not a common size, but still overall less expensive than the involute cutter sets.

As in part two of the video, each cutter tooth does a cut on a different part of the gear tooth.

Karl, I like the idea of the sandwich, and will combine that with some sort of arbor that will clamp over be a tolerance fit. Even wiih loctite, it loosened and had to fix that.

So many things could have been. Probably a combination (comedy) of errors? Let's see if I can screw up the mating gear today while I await a new countershaft gear.

 

[PhilL]

The next gear is the small one. You made a different cutter for that right? Make a practice one out of aluminum or something.

 

[Jack3M]

Phil, same cutter all gear counts. Second video explains between 5:30 and 6:00. Only thing that changes is the rotor table stuff and tool alignment. That is the cool thing about this cutter. It is not an involute cutter which does require different cutters for different tooth counts. This time will do full scrape with Dykem and hand turn the tool in the mill to score a full circle before cutting. Want to make arbors that clamp down first.

 

[PhilL]

Sounds like a solid plan.

 

[Jack3M]

Well that went well. No issues at all for the small gear.

 

[karlw144]

Jack, did you do a scratch cut first? Did you cut full death in one pass?

 

[Jack3M]

Jack, did you do a scratch cut first? Did you cut full death in one pass?

Yes, scratch first then the first cut I worked in to the .067", then just did all the cuts in one shot.

 

[Jack3M]

Well got the new gear blank yesterday. Not a big deal, been fishing and catching. Needed a rest today from good fishing. All prep and prelim work same as before. No telling for sure what I did wrong. But you can see in first photo that it got the scratch treatment all the way 'round, and used Karl's suggestion of sandwiching the part to stop chatter and vibration so I could make full cut each pass and it worked well. Back to fishin' tomorrow, we are even going to get a pair of days to fish and retain Sturgeon.

 

[Jack3M]

Cooler weather is allowing me to fish and work in the shop. Caught two nice Chinooks this morning and cut some keyways this afternoon. Had been fretting as the ones I did today were only 1/16 and I was not about to buy a single broach and guide for just one job. Use a cutoff blade in a holder that actually was for a MicroMark hobby lathe. I was quite surprised how the method worked. Put it in the lathe to hold both the gear and the shaft, tho each was a different setup essentially. Just several passes at 0.010" and it was over. No grief at all.

 

[Jack3M]

G'mornin' folks. Worked on the eccentrics yesterday. I found this a challenging process. Mostly because of holding, the one 'tit' sticks out wider than the part is thick.

As you can see from the photos there is a chunk that needs cut out to make them sorta round. Marked that out first, then did the holes necessary for not only bolting together the two halves but the attach point for the rod and an oiler cup.

 

[karlw144]

Jack, I’m at the same spot with the eccentrics. Wanted to bore and undercut on the lathe, can’t figure out how to hold them. Maybe on the mill in a vice and a special cutter to do the undercut.

 

[PhilL]

If I recall, I held it with a 4 jaw and some very imaginative blocking and a very light touch.

I cut flats on the outside of the bolt ears that I could use to indicate the casting center that direction then I referenced the parting line of the 2 halves for the other direction. Once I had all that set, a facing cut to reference square and you're all good!

 

[Jack3M]

Well, my plan is different, as usual. I have a boring head and an already made cutter for the undercut. If I remember correctly I need to make it a bit narrower. But. Having done this, this way, before, and it was successful, that is the plan. Once you have center it isn't too hard to accomplish with the help of the DRO. After I get some food will attack that.

 

[PhilL]

Absolutely no problem with a different plan. There's no right or wrong. It's what keeps us coming into places like this.

 

[Jack3M]

Feel like crap today, muscle spasms in neck so didn't get so much done. Piddled around with checking the gear mesh and that was great, me happy camper about that.

Also got that powder coated.

Decided to at least look at eccentric. Ended up doing one after all. Karl, photos to possibly help you now. Used a diamond cutting wheel on dremel to do this.

 

[karlw144]

Jack, do you have a picture of your “under cutting” tool?
Good progress on your engine, I’ve got too many other things going on right now, Mery progress is suffering

 

[Jack3M]

Karl, best I have is the one above which is fuzzy. I hear you on busy, fish are distracting me here

 

[Jack3M]

Karl have a photo for you that is in focus. Of note, the upper part that has been cut down is slightly slanted so as to not touch the bearing surface. Then after the 'tooth' is set to center of the strap bearing surface, just move the tool a skosh toward the cut every few passes or so, I actually turned the axle of the machine until a few passes. The tooth should be full depth of the recess in the part and no more.

 

[Jack3M]

Okay, been several days without an update. All excuses, no good reasons. This will be a rather long one I think. First, I had someone suggest I tell more about my process for a given part. I will try, that is the best I can do, but remember I am self-taught and have no formal machining education.

Karl got his eccentrics done and they look great, glad to be of a teensy bit of help Karl.

Next on the make it list was the couplers for the rods. These rods screw into the eccentrics just made and the end that is made here will be the link to hook to the rocker arms. Just so happened to have the perfect size stock in bar, so used that, was low carbon steel. First one was piece of cake, the second one made me make a third. LOL

So, first turned the round stuff on the lathe.


Drilled the through hole for the rod and threaded on the lathe. After cutoff, took that to the mill and used a slitting saw to get the two outer (inner) edges and then a 1/8 bit to cut out the rest....slowly. I neglected to say the hole for the cross pin was done before that and checked for fit with the pin. Those also got cotter pins that were made from music wire. Cross pin is stainless.


Rods were made from drill rod. Had the wrong size rod and if you ever tried to shave off .020" off drill rod you understand the futility. Learned a new trick. The rod was perfect for 8-32 thread, so threaded that. Then since the outer diameter of 6-32 is just slightly less than 8-32 bottom of thread I was then able to get the correct size using the 6-32 die. Dang it worked well too.



Last photo is with the cotter pins made from music wire. . . Like .0045" wire, using jewlers pliers to make the circle bends.


Now, this is a 'midpoint' and possibly I may make the wooden base at this point as it is tippy to the flywheel side. Plan on using ash for the skids and cross ties. Want to leave enough room for water pump, water reservoir, and fuel tank with the ignition down below, toward the back in a wooden box.

 

[karlw144]

Nice going Jack and thanks again for your help. Guess I know what parts I might be making next. Won’t be in the shop for almost a month so will likely forget by then.