Tips/Techniques Metric to Imperial machining conversion

[Susquatch]

Seems @gerritv has me going on machining practices in Europe.

I've realized almost all my carbide inserts list metric machining data right on the insert package but no imperial information. This doesn't work for me. At least not yet anyway. I didn't encounter the metric system till after university. My brain works in imperial not metric.

Doing the conversion itself is trivial with a calculator but I'd like it to be even easier. A set of three graphs covering depth of cut, surface velocity, and feed rate would make life pretty easy. I think it might also expedite automating the thought process the same way that rulers and speedometers have. I can rather instantly convert inches to centimeters and kilometers to miles. Three simple graphs would do that for machining too.

I could just print them out if they were on the internet someplace, but I can't seem to find anything like that. Yet I would have thought they would be everywhere! Best would be one graph with all three lines on it. Or perhaps even just one line with the three axis coordinates in different colors. Or even three vertical or horizontal scales with the two units on each side.

Anybody else have such a thing or know where I can find it?

What do you do?

 

[whydontu]

Do you have a photo of the data? Easy enough to fire up Excel and make new charts.

 

[Susquatch]

Do you have a photo of the data? Easy enough to fire up Excel and make new charts.

I was thinking the same thing. If I have to, that's what I'll do.

But that isn't as effective as a nice plastic graph or a quality metal or even plastic scale that you can set on top of the bench.

I was just thinking that perfection might be one of those triangular engineering rulers with metric and imperial on each side of each edge and each edge having one of the three parameters on it.

Actually it might be better to have the axis down the center of the face and metric imperial on each side.

Edit - Or even better, how about a wheel?

Hard to believe somebody hasn't already done this....

 

[whydontu]

I'm toying with the idea of trying to make a slide rule. A couple of chunks of aluminum, a dovetail cutter, and some engraving. Might take a bit to wrap my brain around how to lay out the scale ratios, but it can't be that tricky. I've got proprietary slide rules for calculating concrete pours, metric conversions, etc. so it should be just a matter of figuring out the ratios. One of these engraved and anodized would be cool.

Design And Build Your Own Circular Slide Rule

You have to really like slide rules to build your own, including the necessary artwork. Apparently [Dylan Thinnes] is a big fan, based on this project he began working on a few months back. The res…

hackaday.com

 

[Susquatch]

One of these engraved and anodized would be cool.

YES! That's exactly what my last thought visualized.

Only three scales are required on the disk. The cross hair is useful but not required.

No logs and such are needed because the conversions are all linear distances.

And yes, an anodized aluminium disk would be cool!

 

[thestelster]

The attached is info from an older Sandvik catalogue. I cropped it to show only steel, not stainless, cast-iron, nonferrous, or hardened data.

Is this the information you're looking for?

 

[Former Member]

I'm toying with the idea of trying to make a slide rule. A couple of chunks of aluminum, a dovetail cutter, and some engraving. Might take a bit to wrap my brain around how to lay out the scale ratios, but it can't be that tricky. I've got proprietary slide rules for calculating concrete pours, metric conversions, etc. so it should be just a matter of figuring out the ratios. One of these engraved and anodized would be cool.

Design And Build Your Own Circular Slide Rule

You have to really like slide rules to build your own, including the necessary artwork. Apparently [Dylan Thinnes] is a big fan, based on this project he began working on a few months back. The res…

hackaday.com

I've got a few for concrete pours, metric conversions, week lead time, etc. Circular slide rule, those are great, just gotta keep the decimal in the right place, and a slide rule or two. Do I use them anymore, nope, got Apps for it all.

 

[Susquatch]

Is this the information you're looking for?

No, it's not. I'm not looking for info. I'm looking for a pocket or workbench reference that simply converts metric insert info to Imperial info or vice versa.

It's trivial to do the math. I just want a little card or dial that has both on a single reference.

Most inserts seem to have metric info right on the box. But I don't think metric. I think imperial. It's a straight forward conversion. But I don't want to even think about stuff like that. I just want to read a recommended feed rate, glance at a card, and instantly know that 0.25mm/rev is the same as 10 thou.

Easy peasy. But couldn't find anything.

 

[DavidR8]

No, it's not. I'm not looking for info. I'm looking for a pocket or workbench reference that simply converts metric insert info to Imperial info or vice versa.

It's trivial to do the math. I just want a little card or dial that has both on a single reference.

Most inserts seem to have metric info right on the box. But I don't think metric. I think imperial. It's a straight forward conversion. But I don't want to even think about stuff like that. I just want to read a recommended feed rate, glance at a card, and instantly know that 0.25mm/rev is the same as 10 thou.

Easy peasy. But couldn't find anything.

Part of it is in the Engineer's Black Book.

https://www.amazon.ca/Black-Books-EBB3INCH-Engineers-Book/dp/0958057141/ref=sr_1_1?crid=3EZJ8H6Z8NGDK&keywords=engineers+black+book+3rd+edition&qid=1704324744&sprefix=engineers%2Caps%2C179&sr=8-1

 

[Susquatch]

Part of it is in the Engineer's Black Book.

Thanks David. That's great stuff, but that's not what I'm after either. I'm looking for a conversion graph for recommended feed rate, cutting depth, and surface speed.

 

[thestelster]

Sandvik has both metric and imperial data on their insert box.

But how about this chart: