Werowance builds a webster

[werowance]

or I am miss understanding what you are saying

 

[Cogsy]

Disregard this post - I think I fudged my math...

 

[Cogsy]

Ok, I think I have it right now. You need to be 0.250 high in the Y direction so you can mark a line at that height. Then you need to mark a line at the same angle as your sloped line, that is 0.250 above that surface as well (running parallel to the sloped line). The point at which these two lines meet is the point you need to drill your radius. I've included a horrible 'sketch' to show what I mean.

 

[werowance]

ah,ok that makes sense and I see where I am making my mistake I was going straight up not angled up. now that's going to be a little difficult to duplicate that angled line exactly. I guess I would extend the top and bottom measurement by .250 to get my intersecting points to draw the parallel angled line. Thanks so much for that explanation.

 

[TonyM]

Up and right gives a different result to two parallel lines as per Brians post.

 

[TonyM]

Thats odd. Cogsy and Werowance posts appeared as I sent mine. Bit of a duplication of effort.

 

[cheepo45]

Why don't you just lay out your lines and cut to them with a .500 end mill?
Instant .25 radius.
Scott

 

[werowance]

Cheepo45, that's a really good idea! and I also learned why my radius layout wasn't working for me either. I think ill go with Cheepo's suggestion but I am glad that I learned how to measure and drill for it as well. Thank you all VERY MUCH!

 

[werowance]

ok, got back to work on my Webster and got along with the bearing supports pretty good until my bandsaw blade snapped. I figured it would, I had put a kink in it accidently sawing some other material and got it in a bind last time I used it.
the both sides were lock tighted together and all sides milled to size and the main bearing hole reamed .4995 and the bottom mounting holes drilled and tapped together. hoping this will keep everything aligned right. then split apart to bandsaw out the unused material. got part of the way there and snap.... hopefully ill be able to pick one up today on my lunch break. the .250 hole for the camshaft rod was reamed .2495 and hope for a press fit. on the bearings, they actually measured .4999 and even with a 4.995 reamer they still slid in the hole with just light finger push in. I would liked to have seen a little tighter but I will put a drop of lock tite on them when I install.

 

[werowance]

thinking ahead a little here, but on the rod, instead of brass or bronze bushings could I substitute a roller bearing on the crankshaft end so that I could forgo that oiler cup hanging off the side? I think I may have a roll of bearings that will fit the shaft if I enlarge the rod a little on that end. just the crankshaft end not the piston end.

 

[Brian Rupnow]

A ball bearing maybe, certainly not a roller bearing. a ball bearing has a hardened inner race. A roller bearing puts the rollers in direct contact with the shaft, which would mean that your shaft has to be hardened, or it will gall very quickly.

 

[werowance]

Thanks, I did mean a ball bearing like used on the crank shaft supports. my mistake on calling it the wrong thing. I was thinking a sealed bearing, I have different assortments for rc car application and such. some came from old postage machines and sorting machines and some from ebay.

 

[Brian Rupnow]

If you use a sealed ball bearing, pry the seals out and discard them, and wash the grease out of the bearings. Either run the bearings dry or use a bit of very light machine oil on them.

 

[werowance]

got along pretty good last night, picked up a new bandsaw blade, some countersincs and got one of the bearing supports done. milling the angle made me a bit nervous as it was very close to one of the vice jaws. but all came out good I think.

 

[Brian Rupnow]

Inside corner looks good. I always drill a hole of the correct diameter and then bandsaw up to the hole, then file away the burrs. I never have a lot of luck with inside corners, that is why I bought the oscillating spindle sander to clean them up better.---Brian

 

[werowance]

Thanks Brian, I was going to do it with a drill but the angle was just difficult to scribe the second line on the angled part so I did the 1/2 inch end mill as cheepo45 suggested. and was really slow and light cuts so I didn't go to far.

 

[bill70j]

thinking ahead a little here, but on the rod, instead of brass or bronze bushings could I substitute a roller bearing on the crankshaft end so that I could forgo that oiler cup hanging off the side? I think I may have a roll of bearings that will fit the shaft if I enlarge the rod a little on that end. just the crankshaft end not the piston end.

This is probably a dumb question - but here it goes:

The crank oiler cup that Webster designed to double as a rod keeper in his plans is threaded to the crank pin. If you run the engine in reverse, that is, the flywheel running CCW when looking at it from the flywheel side, should the keeper be a left hand thread? This would apply to a threaded bearing keeper if that is the route you go.

I ask because I am just completing my Webster build, and the oiler un-threaded itself when I was playing around with it. That happened because the oiler had seated against the rod rather than against the crank pin, which I remedied with a washer. But still, seems it should be a left hand thread.

What do you think?

 

[werowance]

i really hadn't thought about that. Brian do you know? If I do a bearing I will us a washer and thread a nut up tight against the race so that it is stationary (the race) and should run in either direction without an issue that way because both races would be stationary to their corresponding parts and only the balls would be moving and I don't think their would be enough friction to in screw the nut.

 

[Brian Rupnow]

When in doubt--use a little #638 Loctite on the thread. I guarantee that it will not unthread, but if you want to disassemble it after the fact, a wrench will break the Loctite bond quite easily. I never used any left hand threads when I built my engine. If you guys are going to mess around with these little engines, then you damn near have t have a bottle of green Loctite.

 

[cheepo45]

Great progress!