Finger engine revisited

[Bogstandard]

I thought I would show you the backroom stuff that I do, the reason for me going quiet for a while, instead of all my pestering about. Making engines for other people does require a little more care, it is OK to have a few scratches and bumps on your own, but when it is for someone else, it has to be as near perfect as possible. Also because a lot of the parts are true custom pieces, it isn't feasible to make any extras, like if I was making a quick batch production, the time wasted could not be accountable, so if you make a mistake on one piece and rectify it, the other pieces have to be rectified in the same way to make them all the same. So the thing is, don't make mistakes.

I did a build on finger engines last year, and the basic dimensions are taken from that, but because I have free reign on the new design, I will modify the parts as needed, but still sticking to the dimensions.

http://www.homemodelenginemachinist.com/index.php?topic=862.0


I have already started on one of the major parts and turned it into a bit of a post.

http://www.homemodelenginemachinist.com/index.php?topic=1809.0


There are four basic major parts that need a good dose of looking at to give it a bit of pizazz. The flywheel, the conrod, the crank and the finger treadle. The plate work is fairly easy, just a quickie reshape and all will be OK on that score.
So here is as far as I have reached. The flywheels have been trued up perfectly and have had the centres glass bead blasted. The cranks are now shaped and built up to what I want them to look like. The rear standards are stuck together with double sided tape and are rough cut to size, I have drawn out on the plates what I want them to eventually look like.

This second picture shows the contrast produced by bead blasting the flywheels. Once all the work is completed, the flywheels will be sent back to the blasters to be chemically cleaned, just to remove any dirt from the blasted area.
None of these parts are yet polished. This is the preliminary stage where all the scratches and machine marks are removed. When polished the ali will end up looking like chrome and the brass will have a lustre that looks six inches deep.

The problem is I have only just over a week to get these engines finished. It doesn't help when a friend phoned me about an hour ago, for me to make him a new part for his classic racing motor cycle, by tomorrow midday.


John

 

[Bogstandard]

I hacked out the rear standards, and to me they looked terrible, then it just so happened, Bob put up a post about how old things had curvature and a jet age look.

So a quick recycle job on the old, and some new plates cut.

This pic shows the old (crappy) and the new together.

All six plates were stuck together with double sided tape, and over about an hour I rough profiled them to the marking on the end, just by sticking it into the miller and hacking about with a couple of different cutters.

Now they are all roughed out, they will be hand shaped, still stuck together, then separated for final clean and polish.

I might do a little bit of rework tomorrow on the base, to me it doesn't look streamlined enough. But I will have to calculate where the holding screws are going first.

John

BTW, you will notice I still have two datum faces, under the base, and on the front face of the base and the front of the circular bit, this will allow me to drill the mounting holes square before carrying on with the profiling.

 

[bretk]

John,

Have you thought about getting a small ultrasonic jewelry cleaner on ebay? I picked one up with roughly a 6 by 7 by 2" deep pan and it works great for post blasting, tumbling or degreasing chores. Best of all it was less than $40 !

-Bret

 

[Bogstandard]

Bret,

When my workshop is rebuilt in a few months time, there will be one in there, as well as the required bead blaster. I do in fact get jobs done like that for free, but I usually have to wait for 24hours to be done.

Thanks

John

 

[Divided He ad]

I like the retro touch John. For some reason the idea of streamlining something that will never travel through the air is still very appealing? ??? ;D

I can't wait to get my shop back in order and finish my finger engine... seems like ages since I started it! I've got a few new idea's that I hope will work and I think will be very original? (I'll make it and you will all probably say "been there done that!" :big: but I will have enjoyed it all the same )


Ralph.

 

[bretk]

John,

By the way, the finger engines look real sharp! I'm sure the recipients will be pleased.

-Bret

 

[BobWarfield]

I'm intrigued!

Can't wait to see the finished result.

In my shop, the swoopy curves are best accomplished on my disc sander. Eventually I will build a nice belt sander, which offers even more flexibility. The disc gets in the way sometimes.

Cheers,

BW

 

[Bogstandard]

No such luxury for me Bob, I do it by hand.

Maybe I am a bit of a masochist.

John

 

[Bogstandard]

BLESSED ARE THE CRACKED, FOR THEY ARE THE ONES WHO LET IN THE LIGHT!

With me, I've got floodlights as well.

This is real hard going, I am trying to get these engines finished for a deadline of next thursday, and I have a friend who has to get his racing bike finished for the same deadline. So hopefully he won't come with any more jobs and I can hack on with this.

As I said in my last post, I want to do a slight streamlined look, but I am doing it the hard way, rough trim with the miller, then finish off by hand.
I have now got the first pair to very rough finish, they still need to be flatted before final buffing. I have also introduced a bit of felt tip colour to see if it will lift the part a little and hilight the finning. The bearing will not be in the position it is in, it will be hidden on the other side. One side will have a brass spinner, and the other the flywheel, again with a spinner.

When doing something like this, because the bits are on the opposite side of the engine, and are not side by side, a few thou either way will never be noticed, so you can get away with hand shaping. As long as all the datum faces and holes are in the correct position you will have no problems.
These next couple of pics are what it will be like when mounted up.

The previously made rear standards will not be going to waste, I can make new profiled front standards out of them

Do you think the colour works?, and if it does, should the flywheel recesses have the same treatment?, or will it be too much.


John

 

[BobWarfield]

BLESSED ARE THE CRACKED, FOR THEY ARE THE ONES WHO LET IN THE LIGHT!

Do you think the colour works?, and if it does, should the flywheel recesses have the same treatment?, or will it be too much.


John

Yes and yes!

I think the red highlights are totally in keeping with the period. Moreso for a toy, which these are. I supposed if you did one and didn't like it you could sandblast the color back out.

Cheers,

BW

 

[Bernd]

Ditto what Bob said. ;D

If you don't like the way it looks you can always remove the colour.

Bernd

 

[Divided He ad]

John,

You know I am going to have to agree. The extra little bit of colour goes a long way. In the top pic' it looks like the flywheel has a little blue in it already...Or am I seeing things? (this time of the morning that is possible!) Think it's just a light trick but it should look pretty good.
What colour would you do the third engine?


Ralph.

 

[Brass_Machine]

I like the color John. It adds something to the design that fits well.

Eric

 

[cfellows]

You sure do nice work, John. Very innovative and nicely executed. :bow:

Chuck

 

[rake60]

John you always seem to be able to find a way of
making more of something.

I like the color accent!

 

[Bogstandard]

It seems like everyone thinks I am a bit of a guru over things like this.

Nothing could be further from the truth, and I have said this many, many times before, I am doing nothing that anyone else on here could do just as well, and most probably even better.

All I do is use what I see every day and put it into metal, no special machinery, just a bit of experience. A cut here, a tickle with a file there. I think where the difference is, I will try something, and if it isn't successful, I will either recycle it or modify until it looks right. I you never try it, you will never get the unique look you are after.

It looks difficult, but it isn't, all I use usually is a felt tip and a few files. Notice also the files I am using, no handles. These aren't just cheap files, they are good quality, but I grind the tangs off because I find I can use them a lot easier because say when I put a curve on something , my fingers are closer to the curve than if I used a handle, I can feel my way to a shape. The reason I use expensive files is because a lot of cheap files nowadays don't have hand safe edges (that is where one face has no teeth on, usually a narrow side) and this allows me to use finished faces to be guides for other faces I am filing.
If you looked carefully at the parts I have filed up, no two are exactly the same, as I said in my previous post, it doesn't matter, when the engine is finished, the two parts aren't close enough together to be compared. What I will do is match the best pair closest together for the engine I am working on.
The lads that are doing the team build are coming thru with flying colours on this score, I said that they would end up with more than the basic engine, because each person will put a bit of his own design into it, and that is exactly what is happening.

This sort of thing can be done on almost any engine you build, to give yourself a unique looking engine.

Just try it, pretty soon you will be way ahead of me.

Just look at my signature line, it says it all.

John

 

[Bernd]

And here's why they think your a guru. The one part of that statement says it all "I can feel my way to a shape."

Many people don't have that kind of intuition to be able to turn out work like that. Either you have it or you don't. Dosen't mean they'll turn out second rate items, it's just they don't have that third sense that you do.

Bernd

 

[Bogstandard]

The next bit to be made is the treadle, and this has caused me major headaches over the last couple of days. Either I go the way of my previous ones and make it out of ali angle, and it will look like nothing much, or go for a built up one out of brass that will take twice as long, but will hopefully match the engine a little better.

Before I carry on to show you what I got up to today, this is a pic of a brand new BMW front under bumper(I think). I had friends call and their son thought of me when they threw this away at the main agents. It has a very slight transportation twist in it, two men and ten seconds and it would be fixed. As it was they asked if I could put it to good use. There is enough soft 4mm ali to keep me going for years. So yes, I said, I would take it off their hands, so they wouldn't have to take it home with them.

So this is what I eventually decided on, a built up treadle. A spare ali treadle from a previous engine was brought out to give me the dimensions required that my new one will be made to. The shaped brass block is 3 bits of 1/4" brass plate, soldered together, a circle scribed on one end and a couple of lines drawn to give me a teardrop shape, This was then rough cut out on the bandsaw and miller and transfered to my first secret weapon.

Not much of a secret really, a cheap and nasty set of carpenters drum sanders. I mount them so that there is a gap of about 1/32" between it and the drill table. I find I can profile all non ferrous stuff in no time, and keep the sides totally square. I usually have a bit of 1/16" plate under the part to get it away from the gap at the bottom. I have been using these for years, and this drum has never been changed yet.

Here are the three bits desoldered. I checked the circle diameters on them and there was less that 2 thou difference, so it does prove that using the drum sander does keep them very square.

Now for the next secret weapon. Screams from the purists all round. But if you look carefully, this is my four jaw self centreing chuck, with prebored soft jaws and one of the jaws removed. But if you look even more carefully, the circular part of the job is very well supported, more than 180 degrees of the circumference. I have in fact used this with two opposing jaws, and still kept within safe grip limits.
By using it this way, I was able to machine a rough depression in the fingery bit of the treadle, and finish it off with a bit of emery.

This next shot shows the finger bits finished, plus the uprights, which were made using the same principle of all parts soldered together and profiled.

Tomorrow I have to figure a way to join the two parts together, but still retain its slight eccentric looks.

John

 

[chuck foster]

john as usual you are turning out very nice work.

as you said there are lots of people on here that can make the parts and pieces that are required to get the job done.
but you have years of hands on experience and a keen eye for finish and style.

i can fabricate and machine most anything my dad can do, but his ALLWAYS looks better!!!
my parts look to big and heavy (i don,t have an eye for proportions)
i have allways been told that if a 2 x 2 will do the job i use a 6 x 6

chuck

 

[Bogstandard]

Chuck,
I have the honest belief that it isn't all in eye and feel. I think people are scared of trying to do something different, and also want an engine running as soon as possible, so don't clean the part they have done before going on to the next one. By the time it is built, it is just too much trouble to strip it all down again to finish it off.
If you notice how I do things, invariably I finish a part as far as possible before going to the next bit, so at the end it is just a quickie bling over and polish.


Now onto the problem solved bit. How to get the treadle assembled and still make it look quirky, and keeping the centre of the finger doodah on the same axis as the spindle. I thought of all ways, bits of bent rod, angle brackets, but eventually came up with a very easy solution. As always when building prototypes I always leave a bit of extra metal on in places, just in case the area will be needed. I left a bit hanging down below the spindle and decided to attach the tear drop to that.
So the method was to cut a 5/32" (4mm) half round slot into the back of the part and silver solder a bit of rod into it. This was then blended into the part using my little drum sander and given a quickie polish. The one at the back shows just how well it blended in.

Now you can see why I don't like to use flash on finished parts, all the detail is gone.
Why polish it before silver soldering? Because there are a lot of curved parts on this piece, so after assembly, I won't be able to get the right hold points and access to all the part to give it a proper going over, so after it is silver soldered, it will just need a quickie buff over. The straight bits for the upright won't have the same problem, so will be left until it is all assembled.

This is how I devised the way to get what I want, simple but effective, and the tear drops are spot on in line with the spindle.

Now stuck together permanently (I hope). A soak in pickle overnight, and an hours polishing should see them finished.

Only two major bits to go, baseplates (first) and then the conrod, plus a few little joinery uppery bits, and two days to do it in.

Will the masked man get it done?, or will he fail dismally?, all might be revealed in the next exciting episode.

Batjohn and Bandit, his faithful helper.