Where to get Metric plans?

[Cogsy]

The thing is, if we go back the other way, 10.57mm / 25.4 = 0.41614". So either way we are at the limits of our measurement capabilities. At that scale 1 10,000th of an inch or 6 1000th's of a millimeter is irrelevant. If we can't measure that small a difference then we can't know if our 10.57mm is actually off by 6 thousandths.

I can understand issues getting materials and tooling but the argument about lack of precision is lost on me.

 

[barnesrickw]

I googled "convert standard to metric for machining" and found a few videos. Too many to watch and evaluate and send links for, but they are out there.

 

[bazmak]

Why not round it to 10.5mm ctres and same with any matching parts

 

[barnesrickw]

Page 39 of volume 2, Sterling and Steam engines you can Build. He converts one inch to 32mm. "This makes the model 20% larger, but .125in becomes 4mm. .375 becomes 12, and so on".

 

[Swifty]

Hello Swifty,

You are absolutely right, but here is an example of what I am saying:

In the Whittle plans the distance between some bolts is 0.416 in.

Ok, go to mm....0.416 x 25.4 = 10.5664 mm.

I am happy working with ine hundred of an milimiter, but this would require working in tenths of thusands of milimiters....this is going too far for me.

This is not for speaking about drilling and / or reaming holes in inches. I dont have easy access to drills and reamers in inches.´

At last but not least I don´t know how telling me how bad machinist I am for prefer working with milimiters is going to help. No, 25.4 does not solve my question, as everyone here knows how to operate a calculator.

DiegoVV, you are worried about things that you will find are easily conquered. As you know, there are 25.4 microns in a thousandth of an inch, if you drop 6 of them on a dimension, it won't make any difference to the job. If you measure some fasteners you will see that they are under nominal size, this straight away gives you extra clearance on hole alignment. When I'm trying to hit a dimension using my digital readout, if I'm .01mm either way, that's close enough. I might finish machining something on a day when the outside temperature is 40C, but start again the next morning when it's only 15C, the workpiece would have changed all by itself overnight.

I work most of the time in mm, all my drills, except for one 3/4" one, are metric, I have actually had to order a couple of imperial reamers for my current build, they come from Hong Kong, and I'm sure that they will post to most European destinations, just use eBay.

I don't believe that anyone has called you a bad machinist, that's not how this site works, everyone is always willing to offer advice, it's left up to you to accept which advice you want to consider.

Paul.

 

[oasanti]

Hello, I want to coment about two convertion methods from inch to metric.
One is to use a conversor. Its simple, fast and realiable. The other is very simple, faster and very intuitive, it is a very gross simplification, but is uselfull for this hobby, and is to set 1" = 32 mm. This scale up the model about 20% (or scale down if use in the other way) but you get round dimensions. Say: 1/32" = 1mm (real dimension: 0,79375), 1/16" = 2mm (Real dimensio: 1,5875). This idea come from "Steam And Striling Engines You can Build".
I hope it can be helpfull.
Sorry about my english but I refuse to use the language converter and dont know a simplification method !

 

[barnesrickw]

Hello, I want to coment about two convertion methods from inch to metric.

One is to use a conversor. Its simple, fast and realiable. The other is very simple, faster and very intuitive, it is a very gross simplification, but is uselfull for this hobby, and is to set 1" = 32 mm. This scale up the model about 20% (or scale down if use in the other way) but you get round dimensions. Say: 1/32" = 1mm (real dimension: 0,79375), 1/16" = 2mm (Real dimensio: 1,5875). This idea come from "Steam And Striling Engines You can Build".

I hope it can be helpfull.

Sorry about my english but I refuse to use the language converter and dont know a simplification method !

You make a very good point.

 

[barnesrickw]

Oasanti, you make a good point.