CLOSET MODEL ENGINEER WITH QUESTION

[deverett]

Hi Dave

Missed you at GEARS this summer; maybe next year?

The head was was a turning and milling job; last winter I was looking at them and decided that I just wasn't happy with the 3 bosses; so I set them up in the mill and worked them over to better match the mating components. Mixer, Muffler and push rod guide.

Lots of hand work with a Dremel and files to blend every thing in. the finish is a bead blast with very fine beads; they have darkened a bit sitting on the bench.

Hopefully I will get some time to work on them this winter. I have thought about starting a work in-progress thread; we'll see.

Best regards
Dave

Hi Dave

Yes, hoping to be over again next year. I had other commitments this year.

Thanks for the explanation on your workings. Gives the rest of us a standard to aim for. No doubt you will have it up and running by next September?

Dave
The Emerald Isle

 

[Generatorgus]

Mauser, I sure am glad I stumbled into this thread. I bought a Little Brother kit a couple of months ago, and all I new about it is that it is a Briesh model of an Associated Hired Man, it was partially machined and came without the plans. I borrowed plans for the larger scale Briesh, not knowing mine was a smaller engine. Being a bit confused, I posted the question in the Models from castings section and learned it is a Little Brother, or maybe Little Bother from what I'm reading here. I haven't done much with it yet besides looking at the pieces as I haven't got much experience. I did, however, notice the cast iron castings looked kind of sloppy, especially the head and the way it fits the block and have been wondering how the heck I going to make that look good. Comparing it to the plans I borrowed, I could not even figure out which end is up, and can now see from Idahoan Dave's post that it is entirely different.
Dave, is that the model pictured in your avatar? If so, could you post a bigger one and a few others? You did a bangup job on the castings and now I can see what I'm in for, and am encouraging you to please post the build.
I'm also curious as to the actual bore and stroke and the scale of the engine.
GUS

 

[mauser]

Hi Gus, I am a beginner but from the drawings I have borrowed it reads 3/4" bore and 1" stroke. If I have got that wrong I'm sure Dave will be along soon.

 

[idahoan]

Hi Gus

As the story goes the Little Brother started out to be a scale model of an Associated engine but due to having to move the exhaust port it became the Little Brother. This is what I remember reading on the sales brochure from Paul Briesh. You are correct the bore and stroke is 3/4 X 1" and I'm not sure what the scale is because it really isn't a scale of any engine; although it does resemble the Associated.

I'm embarrassed to admit that I have been working on these two engines for more than 10 years. Most of that time spent on the shelf while more important things are attended to. I will rally on them for a weekend and then they sit for months; things just get in the way like paying jobs, work, family, and things that just seem more fun and/or important at the time.

Here are a couple of pictures from last winter when I had both of them running; now they are completely in pieces and I have been, as you have seen working on the castings. Hopefully I will have some time this winter (after the fall outdoor work is completed) to get a little more done on them.

The magneto is a dummy and my original plan was to hide a hall sensor in them. The only problem was due to the close proximity of the spark plug wire to the hall sensor I couldn't keep the sensor from getting fried. The new plan is to hide the sensor behind the cam gear and leave the mag as is. I have modified the castings and made the hall sensor brackets; I think this will work well.

Please if you have any questions please ask; and I will try to get a build thread going on the rest of the project. Who knows maybe it will motivate me to finish the little guys up and be able to start a new project guilt free!

Dave

 

[Generatorgus]

Dave, thanks for the Little Brother history lesson and thanks for the bigger pictures, nice job, the mag is a neat add on. The pictures are giving me a better prospective as to the finished product. I'm relieved to see the head has only three bolts, as I thought the rocker bracket in my parts box was wrong, being way to large for a four bolt pattern. What is the machined area below the big B in the casting for?
I currently have the engine base mounted on a steel plate and have milled the base flat. It's been sitting there in the mill for several weeks waiting for me to drill some mounting holes. I'm reluctant to take the next step without the plans. I wasn't ready to start working on a casting kit yet, don't know if I have enough experience yet. I was thinking of doing another scratch built as I managed to build a half scale Henry Ford engine, without plans, that actually ran for a while, until it lost compression, seems to be the valves. But..., every time I walk past my mill my Little Brother seems to be beckoning me. Being you have a couple of kits, do have a spare set of plans that you could lend or sell me? Probably wouldn't take me much more than ten years or so to finish it ;. ;D

 

[mauser]

Dave, I am in the process of locating all the bits I need to make a fuel feed the same as yours, copper tube, tube bender, fittings etc. as mine has a piece of plastic tubing going from the tank. What diameter tube did you use, it looks like 1/8" or 3mm ? Also, are the elbows and all the fittings you used available online somewhere or did you make them all up yourself? How on earth do you thread copper tube ? I have some serious learning to do ! I can't even find a tube bender that will do 1/8" tube. They all seem to start at 6mm. By the way, I have the first of your two pictures as my screen saver now, so I am constantly reminded how bad mine looks in comparison. Hopefully it will give the push I need to do something about it.

 

[idahoan]

Gus

The machined area that is above the B was one of my plan changes. When you see the original drawings you will notice that the ignition point system that Paul designed was shall we say less than attractive. I re-designed the points to my liking but then decided to go with the dummy magneto instead.
By the way the hall sensor mounted behind the cam gear is a much cleaner way to go.

The machined pocket held a small black Delrin insulator which housed the point that connected to the coil. The ground point was mounted to the pushrod on the brass part that holds the catch blade. Notice that on the other pictures of the engine base that both that feature and the B have been filled in with Devcon.

I will send you a PM in regards to the plans.

Dave

 

[idahoan]

Hi Mauser
You are correct it is 1/8” thin wall brass tubing from the hobby shop. There was no threading involved; on one end it is soldered into the fuel mixer body and on the other end it is soldered into a tube union. The fittings all came from PM Research
To bend the brass tubing it first needs to be annealed; bring it up to a nice dull red with your propane torch and let it cool. You can quench it in water if you are in a hurry.
To be honest I can’t remember exactly how I bent the tube; I probably just formed it around a piece of round stock Once annealed the tubing forms quit easily; you can feel it if it starts to work harden and needs to be annealed again. It would not be uncommon to have to anneal the tubing 2 or three times depending on how complex that bends are.
Screen saver! Wow I feel honored; thanks.
Here is a picture of the tanks with one of the check valve assemblies removed.
Dave

 

[mauser]

Thanks Dave. Did you make those tanks or buy them in ? If they were bought, who sells them ?

 

[idahoan]

Hi Mauser

I made the tanks; they were machined from bar stock. The top of the tank is part of the original stock and the bottom has been soft soldered in.

Dave

 

[mauser]

Dave, sorry for all the questions, I will leave you alone and start work on this engine very soon. Probably a real dumb question but will ordinary 60/40 solder, applied with a flame do for the fuel copper tube fittings ?

 

[Generatorgus]

Mauser, keep up with the questions, it will help me get it done. I have a few of my own.

Dave, if you don't mind, where do you start machining on the cylinder, how do you hold it. The bore seems to be the straightest part of the casting. If it were drilled and reamed to fit a 1/2 rod to hold in the V-groove in my vise, would that serve as a starting point, or is this starting to sound like a dumb question? :-[ Did you make all of the hardware?
Thanks for the offer on the plans, can't wait to see them.
GUS

 

[idahoan]

Hi Mauser

The 60/40 should work fine; I prefer Stay-Brite solder and Stay-Clean flux the solder is 96% Tin and 4% silver. It flows nicely at 430F so it doesn't take a lot of heat to make a nice joint. For delicate work I pound it out flat and cut it into strips with scissors. You may be able to find this or an equivalent product in your local.

The flux comes as a liquid but they also make it in a paste form; I prefer the paste over the liquid as it is easier to apply and stays where you put it.

Dave

 

[idahoan]

Hi Gus

I will start with the easy question; most of the hardware on the engines I have made. I started out using scale hardware from Cole’s Power Models but I ended up changing most of it out. I prefer to use fasteners that look proper on the engine; I don't remember why I chose to make high crown bolts for the mains instead of studs and nuts but it must have seemed like a good idea at the time. Last winter I made new oval pushrod guides instead of the rectangular ones I had previously made (they look much better); also steel instead of brass. I probably will end up making new hardware for these also.

See the problem with dragging a project out this long; is your tastes change, talent and capability improves and you end up redoing a bunch of things because you are not happy with what you had done in the past.

As to machining the cylinder I can't remember the exact steps I used; that was way too long ago. If I did it today I'm sure it would be different.

This casting needs to be properly aligned when mounted to the base so it looks OK. Therefore I would probably set it up so that it would be aligned as it sits on the engine. Then take a light skim off the top of the hopper.

Then this surface could be placed against the solid jaw of your vise and on a parallel. At this point you could pick up the center line of the bore. From here you could machine all the mounting surfaces rough out the bore and drill the mounting hole pattern. I also machined the sides of the flanges so they match the width of the block.

Then all you would need to do would be to mount it on an expanding mandrill of flip it around and put it in a 4 jaw to machine the head surface. Then back to the mill to drill the bolt pattern for the head. Some of this will depend what tooling you have available.

It would be interesting to see what some of the other guys have to say about how to do this.

I hope this helps some.

Dave

 

[Generatorgus]

Dave, thanks for the advice, it is well appreciated, and I guess it was a rather complicated question to answer. Trying to find a good start point for castings is going to be a learning curve.

Mauser, good luck with the soldering project, I never could get solder to build up, I usually just end up with a pile of solder on the floor. I never could figure out how those old auto body guys did what they did with lead.
GUS