Werowance attempts Upshur Vertical Single

[Brian Rupnow]

Okay--I haven't seen it done that way before, but it should work.

 

[werowance]

but I am glad you are watching and looking out for me as I will make plenty of mistakes as I go along so its much appreciated.

 

[Brian Rupnow]

Werowance--I do keep an eye on your builds, and I admire the way you go about doing things. I can see you learning with every new post. I too make mistakes, as it is all part of the learning process.---Brian

 

[Art K]

Brian,
Mine is the same way. It's just got two bored diameters inside. The piston end of the rod is round as well. The rod has the end cap mounted then the holes drilled & reamed. The rest is then turned in the lathe & the excess on the piston end is cut off. Hope that's helpful.
Art

 

[werowance]

i actually saw another engine builder use brass for the wrist pin. he says it holds up just fine for him. he was talking about it in one of his posts concerning how to hold the pin in place so as to not score the piston walls and his solution was to use brass and not worry about it. was thinking about doing the same but wanted to hear if anyone else had tried it and what their results were.

 

[Mow]

I am attempting to build this same engine. I have started but I'm not nearly along as you are. I do have a question about the gears. Would it make a difference if 14 1/2 pressure angle cutters were used instead of the 20 degree cutters? I have access to 14 1/2 degree cutters.

Hopefully I can make a little progress on the engine in the next few weeks. Thank you for posting all this information on your build. It has spurred me into building mine!

Mow

 

[werowance]

i really couldn't say for sure if the PA would matter. but in my opinion as long as the ration was 2 to 1 and the diameters were the same then it really shouldn't matter about the PA. id say give it a shot since you have the 14 1/2 cutters already. the gears he recommends if you buy them are PIC Design part numbers J1-30 and J1-60. not sure if that's a 1 or an L after the J so maybe its JL-30 and JL-60 as the plans appear to have been typed with an old timey typewriter like I had in high schools instead of a word processor or pc.

hopefully one of the more experienced ones can answer for sure on the PA question.

 

[werowance]

I am attempting to build this same engine. I have started but I'm not nearly along as you are. I do have a question about the gears. Would it make a difference if 14 1/2 pressure angle cutters were used instead of the 20 degree cutters? I have access to 14 1/2 degree cutters.

Hopefully I can make a little progress on the engine in the next few weeks. Thank you for posting all this information on your build. It has spurred me into building mine!

Mow

Also, have you posted any of your build logs yet? id like to see them if you have.

 

[Brian Rupnow]

The pressure angle doesn't matter as long as it's the same on both gears. The important thing is to have an exact 2:1 ratio between the two gears. The center to center dimension given in the plans is based on adding half the pitch diameter of the two gears together to get a perfect center to center distance. If you use different gears, then you have to adjust the center to center distance to suit the gears you use. The cam runs on the same shaft as the large gear, and probably if the cam position doesn't change too much +/- 1/16" it should still work okay.

 

[Mow]

Thanks Werowance for the information... I really just started on it but I have to figure out how to post pictures. This will be my first IC engine. I'll have to swallow my pride and be embarrassed because of my weak craftsman ship compared to other engines I see here..LOL

And thanks, Brian. Changing the pressure angle may change the pitch diameter to accommodate the required necessary 60 teeth. I think I have it now.

Looks like the best thing would be to buy the correct cutters.

Thanks for the help

 

[awake]

Changing the pressure angle may change the pitch diameter to accommodate the required necessary 60 teeth.

No, actually changing the PA does not change the pitch diameter for a given number of teeth. (Changing the DP or modulus of the gear is what will change the pitch diameter.) So if your plans call for, say, 30 and 60 tooth, 32DP, 20PA gears, you could instead use 30 and 60 tooth, 32DP, 14.5PA gears without changing anything else.

 

[Mow]

Ok, I will try with the 14 1/2 cutters and see what happens. I will post the results when done.

Thanks for all the help. I don't want to interfere with Werowance's build thread..

 

[L98fiero]

Ok, I will try with the 14 1/2 cutters and see what happens. I will post the results when done.

Thanks for all the help. I don't want to interfere with Werowance's build thread..

Larger pressure angles are for added strength and less undercut on small diameter pinions. According to Boston Gear,
"While 20°PA is generally recognized as having higher load carrying capacity, 14-1/2°PA gears have extensive use. The lower pressure angle results in less change in backlash due to center distance variation and concentricity errors. It also provides a higher contact ratio
and consequent smoother, quieter operation provided that undercut of teeth is not present."
and
"On 14-1/2°PA gears undercutting occurs where a number of teeth is less than 32 and for 20°PA less than 18. Since this condition becomes more severe as tooth numbers decrease, it is recommended that the minimum number of teeth be 16 for 14-1/2°PA and 13 for 20°PA."
https://www.bostongear.com/-/media/...ns/p-1930-bg_engineering-info-spur-gears.ashx

 

[werowance]

I am getting close to getting into the real work on making the piston rod. been milling down a piece of stock to roughly the right size. this will be my first 2 piece rod ever and I know I have seen some people making 2 piece rods out there in the past but when I do a search for 2 piece rod I'm really not getting any good hits. anyone have a post they have done with details about how to do it?

here is what I think I will try if I don't find any more information on it:

start with a piece of stock about .005 or so thicker than what I need. square the end of it. then drill the holes where the cap screw will go and tap the holes. then slice off enough of that end and square it and the cutoff piece back up. then the cutoff piece which I will call the cap from here on I will clearance drill those holes. then from there I will mount the main piece of stock in the vice laying flat, find the edge where I cut the cap off from and then bolt the cap back on and drill /ream through the cap and rod stock together. then tram over and get the hole for the wrist pin side of the rod. the rest of the procedure is no problem for me to do as its like making a single piece rod from there.

and the reason for leaving .005 extra was just incase the cap was a little offset one side or the other when bolted back together and drilled. that way I could just lay the rod on a belt sander and bring it all down to correct thickness with both parts bolted together. what do you all think about this setup? will it work? is there easier better ways? - without CNC lol

thanks in advance.

 

[awake]

weworance, I haven't made a two part rod yet, so take this with the appropriate grain of salt, but what you describes sounds like a good plan to me.

 

[Cogsy]

That's pretty much exactly how I make them.

 

[tjmatx]

I have had good luck with this process on my Upshur. I did, however, add one step; after cutting off the cap, I "folded" it over and placed it on the larger piece of the rod so the two cutoff surfaces were on the same plane. Then I milled off a few thou so the surfaces became exactly parallel (my description isn't very good here). Then I had very good matching surfaces when the cap is bolted to the rod and ready for drilling/reaming.

 

[werowance]

not sure I understand the folded over part

 

[tjmatx]

Yeah, that part I'm having trouble describing... Imagine the top surface of the rod if you lay it flat. Then, after cutting off the cap, lay the rod flat again, place the cap back where it was before cutting it off and flip the cap toward to wrist pin end of the rod so that the two, former top sides are together. (I expect there is a perfect technical name for this but it is beyond my hobby-level of expertise) The two sawn-off surfaces should now form one surface, twice as thick as the stock. Hold the two pieces in the mill in this position and mill the surfaces together to form one perfectly flat surface. Then when you flip the cap back to its permanent position you will have to very well matched surfaces to bolt together. The assumption being that milled surfaces will be better matched than sawn surfaces. If your sawn surfaces are really good, then none of this is worthwhile. (wow, the writing is very lacking here).

 

[CFLBob]

not sure I understand the folded over part

Glad you said that - this lost me several posts ago. I need a picture of what the finished one looks like. Does two part mean that it's split at the crankshaft?