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Elmers #25, my first engine project

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spuddevans:

--- Quote from: Brass_Machine on May 10, 2009, 09:34:12 AM ---Very nice. I will second everyone's statement... you sure you are a newbie??

--- End quote ---

Well, the last time I checked I was a newbie  :D and my progress report may just bare this out.

This afternoon I spent a total of 3 hours to mark out and bore just 1 hole  :bang: :bang: :bang:

The marking out went easy enough, and I even managed to center punch on the "x"  :headbang:  I even got it mounted in the 4 jaw and centered up within a gnats whisker.



The center drilling went well, and even the drilling with progressively larger drills until the bore was 3/8" ( this time I had an imperial drill set, so no metric convertion needed )

It was at this point I realised that the 9.5mm and 10mm reamers I thought I had as a part of a set were not there, the set only went up to 8mm and all are hand reamers, not machine reamers, and so even if the set went up to the needed size they would be useless as the bore is blind and only just over 1" deep.

So this is where the newbie-ness gets a little more obvious, instead of thinking that I could get a correctly sized and type (machine) reamer in a few days time, this numpty decided to spend 2.5 hrs trying to make one.

Sense has finally prevailed after making the bore look rather rougher than when I had just drilled it, and so I called it a day before I totally wrecked the cylinder blank.

So a total of 3hrs to bore one hole, and even that's gonna need reaming out.  :zap:

This is what it looks like,



So, that's as far as I've got.


Tim

Bernd:
Tim,

Well you tried something and it didn't work. That's fine at least you tried.

Here's what I would have done and actually had to do on one of the two I had built. I bored it out with a boring tool. It didn't quite come to size so I made the piston to fit. The bore doesn't have to be the exact size to work, you make the piston to fit the bore. If you feel you messed it up you could try and put it back in the chuck, true it up and bore it out with a boring bar tool.

Bernd

spuddevans:

--- Quote from: Bernd on May 10, 2009, 03:57:19 PM --- The bore doesn't have to be the exact size to work, you make the piston to fit the bore. If you feel you messed it up you could try and put it back in the chuck, true it up and bore it out with a boring bar tool.

--- End quote ---

Thanks Bernd,
I would've bored it with a boring bar but both my boring bar tools are too big  :doh: I need to get a smaller boring bar.

Fortunately there seems to be enough meat left on the blank to bore it out a bit more.

Oh well, one to chalk up to experience  ::)


Tim

bogstandard:
In all honesty Tim, I have all the reamers, but I still prefer to bore cylinders. They turn out much more parallel and round. Plus unless you have a floating tailstock holder, you are almost guaranteed to get an oversized hole with a machine reamer.

Never say you haven't got a boring bar the right size if you have an old drill that is smaller than the hole you are boring. You can just grind a flat face across the end, mount it into your toolpost with one of the ground flutes sitting level, then put a couple of degrees on your toolpost so that the ground tip hits the wall of the bore before the rest of the drill, and away you go.

This is a get you out of the s**t method, not a permanent replacement for a boring bar.

You can try grinding a bit of front rake if you feel up to it. It is really a bit of trial and error, but once you get the hang of it, you will never get stuck again

With regards to making mistakes, it is all in the learning process, they get fewer the more you learn, that is of course, unless you can walk on water.

Bogs

spuddevans:
Thanks Bogs, that will help me out a big load. I've just looked at the prices of machine reamers  :bugeye: :bugeye:

I was thinking that using a reamer would give me a good parallel bore, but if boring the "bore"  :lol: results in a better "bore" I'll stick with that method.

Do you know where I could get a reasonably priced boring bar from that would be usable in say 8mm and upward holes? I have one that works from 12mm and up, but I now can see the need to get something smaller.


On the subject of making mistakes, I truely believe that the man who hasn't made any mistakes hasn't made anything.


Thanks again for your help with this, truely  :mmr:

Tim

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