Another Boll Aero 1.8

[Rodrigo Castellanos]

Hi guys!

yesterday went to my local steel store and got some 12L14 steel bar for my cylinders... think was hard to turn, but not, turns very nicely! i even got a 1/2" reamer, but was so long to fit my lathe, so i must finish the bore with my handmade boring tool, think the result is great! still needs to be polished and "honed".

 

[Steamchick]

Hi Rodrigo, nice bit of machining, but....
I don't know you background, skills , experience, tooling, etc. So I stand to be corrected by experts, and will learn on the way.
I am an engineer, not a fully trained machinist so may have a different perspective from machinists, but not necessarily wrong.
My ideas, based on a teenage apprenticeship in a machine shop, 43 years as an engineer in industry, including some in engine manufacture.
All machines have some mis-alignment, no matter how small, and we aim to overcome this with the "correct" set-up , wherever possible. I see you have the workpiece in the chuck, boring from the main slide. Any mis-alignment between the slide and headstock will cause a tapered bore when set-up this way. With a very accurate lathe this should not be a problem, as the taper over a short length of bore should be well within tolerance limits for the part.
But the theoretical best set-up is to describe a circle with the tool, and progress this circle through the bore. This gives better parallelism of the bore. So when proceeding to your next engine, make a cylinder mount to clamp the cylinder to a datum face, clock this from the chuck to ensure the datum face is truly perpendicular to the axis of the chuck, affix the pre-machined cylinder - which should have allowance for finish boring. Then use a boring tool (mounted in the Mainshaft taper) and progress the tool through the cylinder. This then replicates industrial Boring machines, to give a true circular bore that is parallel and only needs honing to finish.
Enjoy machining!
If anyone wants to teach me the errors of my ways, I'm ready to learn some more!
K

 

[Robsmith]

Steamchick Does what you wrote mean. Mount the cylinder on the cross slide and the tool in the chuck then wind the cylinder onto the rotating tool ??

 

[Steamchick]

Yes. If you buy a boring bar holder to fit the mainshaft taper, you'll be able to index the boring bar to engage an appropriate cut. But you will need to pre - drill the cylinder when set on a fixture on the cross-slide (a drill bit in the chuck will do, or held in a collet chuck in the Mainshaft taper).
As you have a Milling machine that will serve as a boring machine also, instead of the lathe. The set-up is probably easier on the vertical mill.
Turn a blank cylinder leaving 1/16 - 1/8th. In to finish bore. Mount vertically on the mill cross slide. Align work to tool quill. Fit boring bar holder, and bar, and index tool to just touch the drilled bore. Adjust the boring bar to apply the cut (say 0.005"). Run the motor at speed for boring the material, and index down the bore to get a true cylindrical bore. Take it out to -0.003" to -0.001" (undersize). Clean-up to size using a hone to develop the fine finish for a bore. All modern engine bores are made that way on dedicated boring bar machines, but a mill can do exactly the same process.
K

 

[Rodrigo Castellanos]

Yes. If you buy a boring bar holder to fit the mainshaft taper, you'll be able to index the boring bar to engage an appropriate cut. But you will need to pre - drill the cylinder when set on a fixture on the cross-slide (a drill bit in the chuck will do, or held in a collet chuck in the Mainshaft taper).
As you have a Milling machine that will serve as a boring machine also, instead of the lathe. The set-up is probably easier on the vertical mill.
Turn a blank cylinder leaving 1/16 - 1/8th. In to finish bore. Mount vertically on the mill cross slide. Align work to tool quill. Fit boring bar holder, and bar, and index tool to just touch the drilled bore. Adjust the boring bar to apply the cut (say 0.005"). Run the motor at speed for boring the material, and index down the bore to get a true cylindrical bore. Take it out to -0.003" to -0.001" (undersize). Clean-up to size using a hone to develop the fine finish for a bore. All modern engine bores are made that way on dedicated boring bar machines, but a mill can do exactly the same process.
K

Hi Steamchick! thanks for your knowledge! i don´t have a boring head for milling machine, will get one soon. I´m not expert about machining, just simple process, but think this kind of projects are so fun and they call us for learn a lot more!
Still learning a lot, and watching what tools really will need soon, for sure i will want a DRO for my mill, but i need to buy some other stuff before....

 

[Steamchick]

Hi Rodrigo. For a hundred years or so machinists have not had digital read-outs, so don't waste your money on those before you get all the "hard" tooling you want. Indexing Dials on the slide screws are easy when you have practiced reading them. Also, you must always "check, check, check" with your micrometers or vernier gauges, so is is very good practice to do a proper job, rather than rely on some numbers on a read-out. Machinists take years to learn their trade, so it is an "amateur's mistake" to expect to be able to do it all the right way immediately. Short cuts are only safe when you have expertise to make the judgment. First learn the full process from experts, then you'll be able to decide which process is best, and when you can use short-cuts. Digital read-outs are a bit of a short-cut in that they stop you thinking about the process, including measuring and checking, and you just think of numbers.
Money drains quickly when you buy decent tools, so prioritise, so you can do the "making" properly, and invest in tools that will serve you for a lifetime.
Enough of the sermon...
Here's an example from a UK stockist of cheap but usable tools, I guess from China, so you can see the type of boring bar holder I suggest.
Search for:
Soba 75 mm boring bar head set MT4
Also there are plenty of guides on utube...
Enjoy!

K

 

[Tim Wescott]

...
Money drains quickly when you buy decent tools, so prioritise, so you can do the "making" properly, and invest in tools that will serve you for a lifetime.
...

Yea verily. In a production shop, if you're doing a job all the time, it's cost effective to use the very best tool for that job -- because it'll pay for itself over time.

Even in a production shop, though, if you only do a job once in a while (or just once ever) and you can do that job with time and smarts and basic tooling, that's the better way to go.

That Boll Aero is designed to be built with a minimal lathe, and a minimal amount of tooling -- I think that if you find yourself needing every little specialized gizmo on earth to do the job, you may want to reassess what you need vs. what you want, or what you think you need.

 

[Rodrigo Castellanos]

Hi Guys!

some more work done and finally it starts to look like an engine, anyway, a lot of work is missing.

today i made a template to drill my head, using a screw to hold the head, and 2 holes at 90 degrees and a pin. seems to work ok... sadly my measurements were wrong and i need to made a new head... the good thing is that mistake obligate me to work on my carrier stop (think is more like a real brake)

 

[Rodrigo Castellanos]

Hi Guys!

Well, my first head went bad, as holes were out of measure, so after starting another, i decided to make a carrier stop, and it worked well, now i can make grooves or parting with confidence...

so. having 2 heads, i decided to try some anodize, as had trouble with reds in the past, decided to try again (blues and greens seems to be a lot easier to use).

tomorrow will try another gig for make the holes in my new head....

 

[lathe nut]

Thanks for the show and tell, that is a cute little engine, are the plans available for us guys in the US and is there what is called power coating, shows you how much I know, thanks for you time to share, Joe

 

[stanstocker]

The red anodize looks great! As for the first head going bad, well I'm still on my first head and it doesn't seem as sharp as it used to be

 

[Steamchick]

Yea verily. In a production shop, if you're doing a job all the time, it's cost effective to use the very best tool for that job -- because it'll pay for itself over time.

Even in a production shop, though, if you only do a job once in a while (or just once ever) and you can do that job with time and smarts and basic tooling, that's the better way to go.

That Boll Aero is designed to be built with a minimal lathe, and a minimal amount of tooling -- I think that if you find yourself needing every little specialized gizmo on earth to do the job, you may want to reassess what you need vs. what you want, or what you think you need.

Thanks Tim,
I agree. Make do and mend is best for most one-off jobs. But with time, experience and possibly a bit of wisdom or wealth, I have found that the odd tool - like one of these boring tool holders - is just an easier life when I have the job to do. (And retirement is supposed to be a bit easier, isn't it?).
I am currently trying to re-grind the jaws of a 3-jaw chuck that has never been true... maybe time to throw it and get something new? - And my rotary table (Chinese?) seems to have castings make of rubberised iron it is so flexible... I need an old second hand steel one.... Cheap tools bought when that was all I could afford just don't "cut-it", or not where I want it cut!
K

 

[stackerjack]

Thanks for the show and tell, that is a cute little engine, are the plans available for us guys in the US and is there what is called power coating, shows you how much I know, thanks for you time to share, Joe

I do have some plans for the Boll-aero engine. They are as images. There are 25 of them. Here's all of them together, but too small to read properly.

 

[dethrow55]

here is a set of plans for boll aero 18 .

 

[stackerjack]

I do have some plans for the Boll-aero engine. They are as images. There are 25 of them. Here's all of them together, but too small to read properly.
View attachment 118822

Another variation on the Boll-Aero engine:

 

[Rodrigo Castellanos]

hi guys!

Well, i made a new head, holes are now right located but not square.... will give it another try.... some frustration, but think is part of the fun and learn.

 

[Richard Hed]

I do have some plans for the Boll-aero engine. They are as images. There are 25 of them. Here's all of them together, but too small to read properly.
View attachment 118822

A clean copy can be found in "Elmer's Engines"

 

[Tim Wescott]

If the head bolts aren't quite on a square pattern but it fits in only one position, just make a discrete witness mark and don't let anyone but really good friends reassemble the engine.

 

[Rodrigo Castellanos]

Hi Guys!
today i made my 3th head and was perfect! decided tap the gig and use the bolts as a pins, and got a lot better results!

I start to work on my cylinder, having not a lot of tools, decided to use a good eye, rulers, and blades to find the angles and highest spot over the cylinder. i´m happy with the result, so i start to polish and hone the bore... my coarse diamond past was 10 microns, so is taking some time, but hope it get done well as is the first time i do... as most of the engine

 

[Richard Hed]

Hi Guys!
today i made my 3th head and was perfect! decided tap the gig and use the bolts as a pins, and got a lot better results!

I start to work on my cylinder, having not a lot of tools, decided to use a good eye, rulers, and blades to find the angles and highest spot over the cylinder. i´m happy with the result, so i start to polish and hone the bore... my coarse diamond past was 10 microns, so is taking some time, but hope it get done well as is the first time i do... as most of the engine

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Luv ur techniques. I always sez, "Machining is making tools to make tools to make a part".