Changing blueprints between metric and standard....

[Redfinger]

Hello all,

Recently I purchased a Sherline 4500 series mill w/ metric threads, I figured for most of the work I would be doing metric would be the best/easiest way to calculate measurements. But this thread isnt about what is better or worse, inch vs. metric.

Rather it is about a bit of a pickle I am in. I few days after I picked up my mill I got a great deal on a sherline lathe, the probelm is the lathe is standard, but my mill is metric. I know I can change the threads at one point to get my lathe to metric, but in the mean time I have some blue prints of a basic steam engine that I would like to build as my first project, the plans are in metric scale, and most of the machining needs to be done on a lathe.

So is it possible to just change all the etric measuements to standard? Will my tolernaces stay the same? Is just as simple as making the in calculations?

Any help is apreciated guys

Ashton

[Delw]

Get a DRO for both machines and you will be fine.

[diycnc]

just divide all the numbers by 25.4 including the tolerances. this will convert imperial to metric.

for metric to imperial multiply all by 25.4.

[skucku99]

whats standard hehehe

the rest of the world is metric

10mm === 10/25,4=0,393700787 in

jan

[RICHARD ZASTROW]

See. I told you T. Jefferson was right!!!!!!!!!! We should have listened to him in 1790 LOL

Dick Z

[RICHARD ZASTROW]

See, I told you T. Jefferson was right!!!!!!!!!! We should have listened to him in 1790 LOL

Dick Z

[garfieldsimons]

Originally Posted by Redfinger Hello all, Recently I purchased a Sherline 4500 series mill w/ metric threads, I figured for most of the work I would be doing metric would be the best/easiest way to calculate measurements. But this thread isnt about what is better or worse, inch vs. metric. Rather it is about a bit of a pickle I am in. I few days after I picked up my mill I got a great deal on a sherline lathe, the probelm is the lathe is standard, but my mill is metric. I know I can change the threads at one point to get my lathe to metric, but in the mean time I have some blue prints of a basic steam engine that I would like to build as my first project, the plans are in metric scale, and most of the machining needs to be done on a lathe. So is it possible to just change all the etric measuements to standard? Will my tolernaces stay the same? Is just as simple as making the in calculations? Any help is apreciated guys Ashton

25.4 is the magic number. Just divide mm or multiply inches. Tolerance can also be converted. No mystery or voodo. 25.4 is exact. Only problem will be if you are threading. You can always use a the close crossover thread. If you have an old calculator, just set 25.4 as your constant. Nothing to really worry about.

[Redfinger]

Thanks all for the info, I figured it was a pretty simple thing.

Thanks again!

Ashton

[juergenwt]

If you see dim's that look like 6H7 or 12m6 - those are metric DIN/ISO tolerances and you need a table. Google DIN/ISO 286. The tolerances are given in 1/1000 mm.

[easymike29]

Originally Posted by Redfinger .....So is it possible to just change all the etric measuements to standard? Will my tolernaces stay the same? Is just as simple as making the in calculations? Ashton

Ashton
Yes it is as simple as performing the conversions as has already been suggested.
However you must keep one important detail in mind. Do not use a rounded off number in a series of subsequent calculations. For instance, adding a 4 place rounded off number to another rounded 4 place number can result in an error in the 4th decimal. It sounds trivial but in a series of calculations you can be miles off in your tolerance band.

Gene

[veteq]

Originally Posted by garfieldsimons 25.4 is the magic number. Just divide mm or multiply inches. Tolerance can also be converted. No mystery or voodo. 25.4 is exact. Only problem will be if you are threading. You can always use a the close crossover thread. If you have an old calculator, just set 25.4 as your constant. Nothing to really worry about.

Think the number 25,4 is a pain or should i say 25.4 ........

LOL.,

[JerryFlyGuy]

Originally Posted by diycnc just divide all the numbers by 25.4 including the tolerances. this will convert imperial to metric. for metric to imperial multiply all by 25.4.

I think this may actually be incorrect. We need to multiply imp #'s by 25.4 to get metric and divide metric by 25.4 to get imp.

0.50" x 25.4=12.7mm

fwiw