[modeleng] Re: ALERT!! IMPORTANT!! and PS about Model Engineer
- From: "Dud.One" <dud.one@xxxxxxxxxxxx>
- To: <modeleng@xxxxxxxxxxxxx>
- Date: Sat, 20 Oct 2007 15:54:49 +0100
thanks Tim
the main point , that i was thinking of was more of keeping the port face
horizontal & 90 deg in regard to looking from the end face in relation to
the bore centre line , but yes i understand what you meant Tim .
Dave
----- Original Message -----
From: "Tim Kirby" <trk@xxxxxxxxxx>
To: <modeleng@xxxxxxxxxxxxx>
Sent: Saturday, October 20, 2007 3:04 PM
Subject: [modeleng] Re: ALERT!! IMPORTANT!! and PS about Model Engineer
> On 10/20/07 4:05 AM, "Dud.One" <dud.one@xxxxxxxxxxxx> wrote:
>
>> on another point , i am building a Rob Roy as my first Loco and i have
>> come to
>> the point of the castings for the cylinders , how do you get a reference
>> for
>> the steam chest centre line and the fact of making the port face
>> tangental to
>> the cylinder bore .
>
> I don't think you want to make the port face tangential, if I remember
> Rob Roy cylinders correctly :) - you want the port face and bore to be
> parallel.
>
> Exactly how you achieve this is going to depend somewhat on the tooling
> you
> have available, but in terms of machining personally, I would look to
> machining the port face first to give you a datum to work from. The
> casting
> should be pretty square, so you shouldn't be taking wildly different
> thicknesses of material when you do that work. Once you have that surface
> to
> work from you can then mount against that face and bore the cylinder; with
> a
> bore to work from you can mount the cylinder on a mandrel and square the
> ends... though, as I said, how you do this may vary depending on whether
> you
> are doing this with a traditional lathe or if you are in posession of some
> piece of multi-axis CNC machining center. I've never built with one of the
> latter; the techiques might be very different...
>
> Alternatively you could probably try and cut the bore first, then square
> the ends to the bore and use the ends as your datum and then cut the port
> face from them, but I think the former order would be easier.
>
>> may be a dead easy question for you guys , but i don't want to screw them
>> up
>
> Knowing the right way to do it isn't going to guarantee you don't screw
> them
> up, Dave :) Just remember to make sure that your castings are securely
> mounted when you machine them. There is little as distressing as having
> put
> many hours into a casting only to have it move and mangle itself...
>
> Tim
> --
> Tim Kirby trk@xxxxxxxxxx
>
>
> MODEL ENGINEERING DISCUSSION LIST.
>
> To UNSUBSCRIBE from this list, send a blank email to,
> modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject
> line.
MODEL ENGINEERING DISCUSSION LIST.
To UNSUBSCRIBE from this list, send a blank email to,
modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.
Other related posts:
