Sunday, June 2, 2013

Graphite piston size issue (builders, please note!) (4IN1)

Here's an e-mail I received from Wayne Linfield on June 1, 2013:


At Christmas I received a 4 in 1 engine kit with the Graphite & Bearings kit. I am now getting around to building the engine. I find that the graphite piston is too small. The data sheet specifies the diameter as 1.045" but the part I received is only 0.997".Having already bored the cylinder out to 1.000" it is too small to fit properly.Is it possible to send me one the correct diameter?


And my reply:



Hmmm - never noticed that before.  That must be a typo, because the data sheet for the "Duplex" engine kit shows 1.000", which is the same stock.  I'll have to fix that on the 4-in-1 kit packing slip.

Looking at page 10, it shows the cyl diameter is 1.000".

We do not offer graphite larger than 1".

Although I am not a machinist, I would think it would be wise/prudent to make your parts around any pre-manufactured parts.

Sometimes, bearings are slightly smaller by a thousandth or two from what the plans anticipate.  Once or twice a customer has also complained about that.  Of course, I have no control over manufacturers to make bearings the exact size as the plans specify.   You must allow for generally accepted mass-production size tolerances.  Not unlike 2x4 lumber is actually 1.5" x 3.5"?

Since your cyl is now oversize, I suppose you could insert a stainless steel sleeve like Dad did on his.  Then you won't have to make another cyl.

Sorry about that!

No comments:

Post a Comment