David’s layout is better than mine, time to move columns in my CAD file.
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SFM RPM Chart
- Thread starter whydontu
- Start date
Do you want the Excel file?
I like yours better. You two guys are obviously not RPN fans. Inputs first, then operation. Not input, operation, input.
Doesn't really matter though. Hairy guy can't find his phone.
I am not an RPN fan as I don’t speak Tagalog
I think you’re right. I’ll split the chart into two versions. And engrave each chart on my 3x5 plate, one on each side. Photos to follow.
Dabbler
ersatz engineer
so here is my confusion. In the original chart, I ignored 'closest multiplier'.... But now since it appears on both sides, please tell me what I'm missing.
For years I've been setting speed of cutting based on how the cutter works, kind of an internalized chart. I *really love* codifying it onto a chart, but I now wonder about this multiplier thing. Is it just the nomenclature that is confusing me?
For years I've been setting speed of cutting based on how the cutter works, kind of an internalized chart. I *really love* codifying it onto a chart, but I now wonder about this multiplier thing. Is it just the nomenclature that is confusing me?
Too many ideas now.
The <Closest Multiplier> is maybe too wordy. It just the simplest factor to multiply the 100 SFM RPM value to compensate for the specific material recommended rotational speed.
But now I’m wondering if I can condense this into a more traditional material/rpm chart that would fit onto a 3x5 file card and still be legible. Tomorrow’s project 42c.
I am not an RPN fan as I don’t speak Tagalog
Lost me on that one David. What's the connection between RPN and Tagalog?
Btw, it just so happens that one of my brothers is learning Tagalog right now. Interesting language.
First hit on Google for RPN was Radio Philippines Network
Tomc938
Ultra Member
I understood the first layout, but this layout makes even a little more sense to me.
This is awesome! Thanks for putting it together and sharing with us.
@whydontu - All joking around aside, I like the combined charts just fine.
You don't really need a separate lathe and mill column for the rpm charts. Diameter, rpm, and sfm are the same regardless. One column with diameter and RPM at 100 sfm is all that is needed. Just drop the "workpiece" and "cutter" headings and make 1 chart.
I think the main confusion others have had, relates to the human tendency to use horizontal or vertical rows and columns. It is isn't intuitive that you take one number from one row/column and multiply it by a number from another row/column someplace else on the chart.
But if you go back to your previous separate charts, it's a bit easier to see.
My advice is to separate (or add a margin between) the two sections and title the two relevant columns as A and B. Then just above the statement that carbide is double, add a formula. RPM = A x B. You could also label that as TARGET RPM = A x B
If you wanted to have just one chart, you could also combine the mill and lathe chart by having 3 columns for the material chart. One for material, and one each for the B factor for the Lathe and Mill.
You don't really need a separate lathe and mill column for the rpm charts. Diameter, rpm, and sfm are the same regardless. One column with diameter and RPM at 100 sfm is all that is needed. Just drop the "workpiece" and "cutter" headings and make 1 chart.
I think the main confusion others have had, relates to the human tendency to use horizontal or vertical rows and columns. It is isn't intuitive that you take one number from one row/column and multiply it by a number from another row/column someplace else on the chart.
But if you go back to your previous separate charts, it's a bit easier to see.
My advice is to separate (or add a margin between) the two sections and title the two relevant columns as A and B. Then just above the statement that carbide is double, add a formula. RPM = A x B. You could also label that as TARGET RPM = A x B
If you wanted to have just one chart, you could also combine the mill and lathe chart by having 3 columns for the material chart. One for material, and one each for the B factor for the Lathe and Mill.
How 'bout this one? This will engrave nicely on a 3x5 file card. This is the Lathe values, I intend to engrave a 3x5 aluminum sheet with Lathe on one side and Mill on the other. The crosses are for punched holes.
I engrave 0.015" deep, then fill the lines and letters with nail polish. So I can use different colours for text, lines, and the A & B flags.
I engrave 0.015" deep, then fill the lines and letters with nail polish. So I can use different colours for text, lines, and the A & B flags.
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I like it a lot! I especially like:
* It's more intuitive now
* The math is there
* Rows/columns are separate
*** 3x5 file card *** YES!
KeeponDragon
no problems... just challenges
For my primitive reptilian brain...this one makes the most sense...
I never did well in math classes of any kind...
In the work shop side of things...it was the hands on processes that I could grasp the quickest...
book learning just isn't my forte'...
This entire thread has been informative....AND highly entertaining with the "internal thought processes" shared by David and Squatch...omg...guts hurt now
DropBox link to both charts, in multiple formats.
www.dropbox.com
Feel free to ask for modifications. The SFM values I've used are what works with my low-HP lathe and mill, if you're running a 10HP Bridgeport and a Monarch 10EE the values might be a bit conservative. I was taught "if the cutter breaks, it's running too slow, if the cutter turns blue you're running too fast", and my values might not work for your setup.
Dropbox
Feel free to ask for modifications. The SFM values I've used are what works with my low-HP lathe and mill, if you're running a 10HP Bridgeport and a Monarch 10EE the values might be a bit conservative. I was taught "if the cutter breaks, it's running too slow, if the cutter turns blue you're running too fast", and my values might not work for your setup.
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