# David Kerzel Engine - problems



## Bastelmike (Oct 10, 2012)

Hello All,

I wonder if anyone here has completed the Kerzel Engine?
I'm trying to make a 3D CAD model of it as a base for some metrification. But I must admit I don't come along well because problems in the plans.

For example Base plate:
Some counterbores have a depth so they come dangerously close to the surface. Depending on the radius You manufactured the plate with, they break the opposite surface. I wonder why those counterbores are specified much deeper than standard?

Mike


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## Bastelmike (Oct 10, 2012)

Next part Base sides:

The part I gave up CAD work for now - probably correcting this problems would change most dimensions in the drawings.

1) the point given for center of the main bore is outside the base side, and not on the parting line between base side and cap where it should be.
See which dimensions I got after correcting this

2) the threads in those sides interfere with each other. You'll see in the pics how the part would look after cutting it in two halves. 

View attachment BaseSides 3Drein.pdf


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## tel (Oct 10, 2012)

There have been at least three builds described in these august pages.

In my own case I just work around those sorts of problems as I find 'em - from memory I shifted the underside bolts outward in your problem #2

With problem#1 - the point is, in fact, on the part line, but the location is derived from the bottom and tall end of the piece. In truth, I found these pieces a bit of a headache but, in the end, I think I marked out the centre as per the drawing, then worked the angled line in to bisect the point. Been a while now, and I can't really be more exact than that.


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## Brian Rupnow (Oct 10, 2012)

There ya go my boy!!! If you are modelling in CAD I can probably send you a .XT parasolid file of the whole engine modelled in Solidworks if you want it.
http://www.homemodelenginemachinist.com/f31/brian-builds-kerzel-hit-miss-i-c-10091/


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## Bastelmike (Oct 12, 2012)

Brian Rupnow said:


> There ya go my boy!!! If you are modelling in CAD I can probably send you a .XT parasolid file of the whole engine modelled in Solidworks if you want it.
> http://www.homemodelenginemachinist.com/f31/brian-builds-kerzel-hit-miss-i-c-10091/


 
Hi Brian,

thanks for Your offer. Might be helpful - my CADs can't open Solidworks but I got a viewer for Solidworks. 

@Tel

Did You encounter some problems with the threaded holes in the Cylinder Base Side, these upper #4-40 threads'?
If I'm not mistaken, it looks this way:

Mike


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## Brian Rupnow (Oct 12, 2012)

Speaking from my own experience, now is a good time to research bottoming taps. I almost ruined a cylinder for a steam engine I was building by drilling thru into the bore to get deep enough holes to put a thread in. Luckily I was able to sleeve the cylinder and save it. With bottoming taps you can drill a very shallow hole, partially thread it with an ordinary tap untill an ordinary tap "bottoms out" in the hole, then use a "bottoming tap" to finish putting the threads in.---Brian


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## Draw-Tech (Oct 31, 2012)

Hi Mike 

Jack from Florida, Have been building same engine and I have drawn it in Autodesk Inventor.As for the holes in the Cylinder body does not mater because the cylinder liner seals it. I will be using water im my engine, but I have added two o-ring grooves in the body, and put silicine seakant on the screws,If you would like a step, iges, or dwt file which can be opened with Design Review downlosded from Autodesk.com for free. Contact me at [email protected] I also have designed a cart for the engine.

Jack

drae-tech on this site. 

View attachment H & M Assembly.pdf


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## creast (Feb 19, 2013)

This is a bit late but if anyone wants to download my version (available in SolidWorks or STEP) go to
http://grabcad.com/library/hit-and-miss-engine-kerzel-design--1


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## creast (Feb 26, 2013)

Hi Jack,
How far have you got with building the H&M engine?
Mine is almost complete and I am trying to get it to run before I finish it with the regulator bits... no luck so far :-(


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