calling all webster or tiny builders

[Speedy]

I am going to start my next engine.
trying to decide between the webster or putputmans tiny.

need to order material but dont see a list for either, can anyone help me?
how does one go about buying metal and not being short handed or left over.

Mike

 

[Brian Rupnow]

If you are going to build the Webster, then obviously you have downloaded the free plans. Make a list of the different materials based on the minimum size of bar stock or round stock you need to make each part and add 1/4" to each length to give yourself room to square everything up in your lathe or mill or trim on your bandsaw. Most machine shops carry an inventory of the most common sizes of mild steel, cold rolled steel and aluminum and will cut the peices you require to length for a nominal fee. If you want to check out a Webster build, here is mine.---Brian---if you want to talk about it, call me---My contact information is on my web page.
http://www.homemodelenginemachinist.com/f31/anybody-want-guess-7687/

 

[mikegw1961]

Mike

I have a spreadsheet of the material required for the webster. I have just ordered some of the material ready to start after I have finished the Firefly 46

It has UK prices from M-Machines but should give you a rough idea.

Regards

Mike

View attachment Webster BoM.xlsx

 

[lensman57]

Hi Mike,

Follow Brian's instructions. The BOM could be taken from the Webster engine plans, and likewise from the putputman's tiny plans. I am just about finishing the Webster at the moment and comparing the size the tiny may need less precious metal.

Good Luck,

A.G

 

[Speedy]

any recomendations on cylinder,
says either 12L14 steel or cast iron.

whats the better pick?

I might opt for liquid cooled cylinder.

 

[Brian Rupnow]

Cast iron is the best of the best. That being said,ordinary mild steel will work just as good---thats what I used. I used a viton o-ring on mine with an aluminum piston (the specs are all in my build thread). I would stay away from 12L14 because it is a real rust magnet, and there is a lot of condensation in these small i.c. engines.

 

[Speedy]

does ordinary mild steel have a code such as 12l14?

will the viton oring be sufficient if the engine is working? I plan on turning a small stepper motor to power a miniature l.e.d light.

 

[Brian Rupnow]

Ordinary mild steel is 1018 to 1020. The formulae for 12L14 steel is entirely different. the Viton o-ring will work fine and let your engine do "real work". If you want a real "show and tell" on Webster engines, come on up to Barrie---I'll show you some of the 15 engines I have built and show you my Webster doing "real work".--Like I said, my contact info is on my website.---Brian

 

[lensman57]

Hi Brian,

I hope Micheal doesn't mind if I asked a question. I eventually finished the engine this afternoon, subsequently I sacked the piston with the cast iron rings, it just didn't seem to give enough compression. I had already turned another piston to suit the Viton O ring and this one is a hell of a tight fit in the cylinder, however no matter how I tried I don't seem to detect any movement of the intake valve, I know it is atmospheric pressure operated but how can I make sure that it is doing what it is supposed to as there doesn't seem to be any apparent fuel flow in to the Traxasx carb from the tank, and of course there is no ignition. The electronic ignition is doing its job and I get a very good spark about 15 Deg before TDC.

Many thanks and regards,

A.G

 

[Brian Rupnow]

Lensman--You won't see any movement of the intake valve if you are turning it over by hand. Put your variable speed electric drill on the output shaft and turn it at about 1/3 the drills full speed. Then you will definitly see the intake valve move---IF---your rings are sealing----if the spring on the intake valve isn't too stiff-----if your head gasket is sealing properly----if its not sucking air around the valve stem----if your exhaust valve is really sealing and its not sucking air back thru the exhaust side. There are about a dozen more ifs. ---Brian

 

[Speedy]

no worries A.G.

Brian do you think its necessary for me to fly cut faces? I couldnt get exact thickness at the metal mart but they are close.
I dont think the base cares all that much but maybe the sides?

 

[Brian Rupnow]

This will fly directly in the face of what I have heard from other engine builders, but I don't fly cut anything. Its a lot more work for VERY little gain. If its a critical mating surface that simply must be perfectly flat, then yes, either a flycutter or a 1" dia. endmill, but for 99% of what you will do, you don't need to flycut.