X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail12.syd.optusnet.com.au ([211.29.132.193] verified) by logan.com (CommuniGate Pro SMTP 5.2.12) with ESMTPS id 3458204 for flyrotary@lancaironline.net; Thu, 29 Jan 2009 04:05:33 -0500 Received-SPF: pass receiver=logan.com; client-ip=211.29.132.193; envelope-from=lendich@optusnet.com.au Received: from acer6e40e97492 (d58-108-104-247.dsl.nsw.optusnet.com.au [58.108.104.247]) by mail12.syd.optusnet.com.au (8.13.1/8.13.1) with SMTP id n0T94lda008119 for ; Thu, 29 Jan 2009 20:04:49 +1100 Message-ID: <7C3CF19793964C65858E12F9DA25E3BC@acer6e40e97492> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] reverse engineering Date: Thu, 29 Jan 2009 19:04:47 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0056_01C98244.73DDEA00" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_0056_01C98244.73DDEA00 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I am designing some parts that must fit the drive pulley hub tightly. = my question is, since I've never done this before, involves measuring = the existing pulley. can I assume that measurements are typically even = numbers, and that a hole diameter isn't 49.12mm for instance? I can fit = drill bits thru the bolt holes and drive pins to get accurate = measurements there. I discovered that, indeed, the bolt holes aren't at = 90 degrees, but appear to be at 85 and 180 degrees, which means the = reluctor wheel only fits one way. I located the holes by measuring the = distance between adjacent holes. again, can I assume an offset of an = even 5 degrees? I am using some electronic calipers from harbor = freight. do you find these accurate enough? kevin Kevin, Th Rotary is indeed built in Metric, It amazes me how some can measure = in inches, but when converted back to metric to a couple of decimel = places. Something lost in the conversion I'm sure - so stay with Metric. However, having said that there are many instances where mm are to 2 = decimel places - that goes for degrees as well, sadly. I guess nothing = can be built/planned that exactly. The e-shaft is in full mm ( for the most part) but ground for = tolerances, so I asume the pulleys are drilled in mm as well, although = haven't checked. Hope that helps, and let us know what you find. George (down under)=20 ------=_NextPart_000_0056_01C98244.73DDEA00 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
I am designing some parts that must = fit the=20 drive pulley hub tightly.  my question is, since I've never done = this=20 before, involves measuring the existing pulley.  can I assume = that=20 measurements are typically even numbers, and that a hole diameter = isn't=20 49.12mm for instance?  I can fit drill bits thru the bolt holes = and drive=20 pins to get accurate measurements there.  I discovered that, = indeed, the=20 bolt holes aren't at 90 degrees, but appear to be at 85 and 180 = degrees, which=20 means the reluctor wheel only fits one way.  I located the holes = by=20 measuring the distance between adjacent holes.  again, can I = assume=20 an offset of an even 5 degrees?  I am using some electronic = calipers from=20 harbor freight.  do you find these accurate=20 enough?      kevin

Kevin,

Th Rotary is indeed built in Metric, It = amazes me=20 how some can measure in inches, but when converted back to = metric to a=20 couple of decimel places. Something lost in the conversion I'm sure - = so stay=20 with Metric.

However, having said that there are = many instances=20 where mm are to 2 decimel places  -  that goes for = degrees=20 as well, sadly. I guess nothing can be built/planned that = exactly.

The e-shaft is in full mm ( for the = most=20 part) but ground for tolerances, so I asume the pulleys are = drilled in mm=20 as well, although haven't checked.

Hope that helps, and let us know what = you=20 find.

George (down=20 under) 

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