Radius gauge and reverse engineering

Printable View

Dec 22, 2018, 03:28 AM
tonyfoale

3 Attachment(s)

Radius gauge and reverse engineering

I recently posted about some reverse engineering that I needed to do to replicate some classic motorcycle crankcases at
http://www.homemadetools.net/forum/h...029#post120271

Continuing on from that I needed to measure some corner and other radii, there are many possibilities for such tasks, for example MichaelMoore recently posted his templates at
http://www.homemadetools.net/forum/r...348#post122031

This current post is about a set of radius gauges that I built using a digital gauge as the measuring element.

Attachment 27153 Attachment 27154 Attachment 27155

I have put the full story in a PDF which can be seen and/or downloaded from:
Tony's radius gauge
I have also written a simple bit of software to perform radius calculations and that is linked in the PDF file. I will also add a video in the next few days.
Dec 25, 2018, 01:44 AM
yves78

You did it

Thanks a lot Tony : 2 days ago, I was just thinking to build something similar in order to evaluate a radius.

That's very nice to get an idea of your solution for that.

I take also the opportunity of that reply, to thank you for your pdf explanation documents, always clears and usefuls.
Dec 25, 2018, 09:48 AM
tonyfoale

Quote:

Originally Posted by yves78

Thanks a lot Tony : 2 days ago, I was just thinking to build something similar in order to evaluate a radius.

That's very nice to get an idea of your solution for that.

I take also the opportunity of that reply, to thank you for your pdf explanation documents, always clears and usefuls.

Glad that you find it useful. If you make something like it be sure to post it here.
Dec 25, 2018, 11:52 PM
NortonDommi

Thanks, I've put this in the to do list for Winter.
Dec 26, 2018, 09:42 AM
Toolmaker51

Quote:

Originally Posted by NortonDommi

Thanks, I've put this in the to do list for Winter.

WELL it's winter here, hint hint. Weeks and weeks worth...
Dec 26, 2018, 09:44 AM
Toolmaker51

Quote:

Originally Posted by tonyfoale

I recently posted about some reverse engineering that I needed to do to replicate some classic motorcycle crankcases at
http://www.homemadetools.net/forum/h...029#post120271

Continuing on from that I needed to measure some corner and other radii, there are many possibilities for such tasks, for example MichaelMoore recently posted his templates at
http://www.homemadetools.net/forum/r...348#post122031

This current post is about a set of radius gauges that I built using a digital gauge as the measuring element.

I have put the full story in a PDF which can be seen and/or downloaded from:
Tony's radius gauge
I have also written a simple bit of software to perform radius calculations and that is linked in the PDF file. I will also add a video in the next few days.

I can't recall anything on the market or DIY anything like it. Seems Tony, you knock two thirds the competition off before they get in the pit let alone on track. Said other way; He's lapping them right inside the shop?

Further; Jon. Is there a HMT.net logo decal for Tony's machine? What an audience!
Dec 26, 2018, 03:31 PM
tonyfoale

I have just enhanced the software to allow calculation of the curve radius and centre coordinates when the XY coordinates of three points on a curve are known.
This is useful if you use the DRO on a milling machine to determine the coordinates of three points. This does not need the radius gauge described above.
The link to the software is the same as that in the PDF RadiusGauge.pdf
Dec 26, 2018, 04:46 PM
tonyfoale

I have not had time to edit the video that I promised so I have just uploaded a 3 minute unedited version of the most interesting part of the radius gauge construction.https://motochassis.com/FileDump/Rad...adiusGauge.wmv
Dec 27, 2018, 07:05 AM
DIYer


Thanks tonyfoale! We've added your Radius Gauge to our Measuring and Marking category,
as well as to your builder page: tonyfoale's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/homemade-radius-gauge-3"> <img src="/uploads/219843/homemade-radius-gauge-3.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/homemade-radius-gauge-3">Radius Gauge</a> <span> by <a href="http://www.homemadetools.net/builder/tonyfoale">tonyfoale</a></span> </div> <div class="tags">tags: <a href='http://www.homemadetools.net/tag/gauge'>gauge</a>, <a href='http://www.homemadetools.net/tag/radius'>radius</a> </div> </div> </div> </div>
Dec 28, 2018, 03:23 PM
Jon

Congratulations tonyfoale - your Radius Gauge is the Homemade Tool of the Week!

Another record-breaking week around here, with many excellent builds. This tool really stood out, and was especially well-documented.

Some good picks from this week:

Mini Lathe Slow Speed Feed by jjr2001
Optical Punch by Canobi
Bar Cutter by jealpaul
Multifunction Scribe by Dimitris Polychronis
Tall V Block by rossbotics
Large Drill Bit Modification by Kovanca Polock
Bandsaw Mount Modification by Steved53
2x72 Belt Grinder by DanLins
Disc Sander by Vyacheslav.Nevolya
Riving Knife by Rorschach
Simple Puller by liberal
Hand Stamp Guide by rgsparber
Turning Saw by threesixesinarow
Bevel Guide by LastingBuild
Extra Wide Chisel by Make Things
Center Punch by Frontier Forge
18650 Battery Charger by Lahis
Plumbing Spanner Wrenches by garage nut
Drain Pipe Indicator by garage nut
Engraving Chisel by Frontier Forge
Zero Clearance Insert by Rorschach
Capacitor Tester by garage nut

tonyfoale - we've added your tool entry to our All Homemade Tool of the Week winners post. And, you'll be receiving a $25 online gift card, in your choice of Amazon, PayPal, or bitcoin. Please PM me your current email address and gift card choice and I'll get it sent over right away.

This is your 9th Homemade Tool of the Week win! One more and you'll join rossbotics and mklotz as a 10-Time Homemade Tool of the Week winner. Here are all of your winning tools:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/forum/home-made-horizontal-milling-machine-55333#post81620"> <img src="/uploads/162905/homemade-horizontal-milling-machine-2.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/forum/home-made-horizontal-milling-machine-55333#post81620">Horizontal Milling Machine</a> <span> by <a href="https://www.homemadetools.net/builder/tonyfoale">tonyfoale</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/mill'>mill</a> </div> </div> </div> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/forum/grinding-machine-drum-brakes-55587#post82147"> <img src="/uploads/162657/homemade-drum-brake-grinder.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/forum/grinding-machine-drum-brakes-55587#post82147">Drum Brake Grinder</a> <span> by <a href="https://www.homemadetools.net/builder/tonyfoale">tonyfoale</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/grinder'>grinder</a>, <a href='https://www.homemadetools.net/tag/brake-drums'>brake drums</a> </div> </div> </div> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/forum/shock-dyno-shock-absorber-dynamometer-56478#post83755"> <img src="/uploads/163993/homemade-shock-absorber-dynamometer.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/forum/shock-dyno-shock-absorber-dynamometer-56478#post83755">Shock Absorber Dynamometer</a> <span> by <a href="https://www.homemadetools.net/builder/tonyfoale">tonyfoale</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/suspension'>suspension</a>, <a href='https://www.homemadetools.net/tag/measurement'>measurement</a> </div> </div> </div> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/forum/valve-holding-measuring-collet-58294#post87183"> <img src="/uploads/166061/homemade-valve-holding-collet.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/forum/valve-holding-measuring-collet-58294#post87183">Valve Holding Collet</a> <span> by <a href="https://www.homemadetools.net/builder/tonyfoale">tonyfoale</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/valve'>valve</a>, <a href='https://www.homemadetools.net/tag/holder'>holder</a>, <a href='https://www.homemadetools.net/tag/collet'>collet</a> </div> </div> </div> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/homemade-laser-aligner"> <img src="/uploads/168729/homemade-laser-aligner.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/homemade-laser-aligner">Laser Aligner</a> <span> by <a href="https://www.homemadetools.net/builder/tonyfoale">tonyfoale</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/alignment'>alignment</a>, <a href='https://www.homemadetools.net/tag/laser'>laser</a> </div> </div> </div> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/forum/double-edged-fly-cutter-63995#post100445"> <img src="/uploads/205514/homemade-double-edge-fly-cutter.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/forum/double-edged-fly-cutter-63995#post100445">Double Edge Fly Cutter</a> <span> by <a href="https://www.homemadetools.net/builder/tonyfoale">tonyfoale</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/flange'>flange</a>, <a href='https://www.homemadetools.net/tag/fly-cutter'>fly cutter</a> </div> </div> </div> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/forum/homemade-vertical-bandsaw-66678#post108045"> <img src="/uploads/211089/homemade-vertical-bandsaw-5.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/forum/homemade-vertical-bandsaw-66678#post108045">Vertical Bandsaw</a> <span> by <a href="https://www.homemadetools.net/builder/tonyfoale">tonyfoale</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/bandsaw'>bandsaw</a> </div> </div> </div> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/forum/diy-surface-grinder-67127#post109600"> <img src="/uploads/212251/homemade-surface-grinder-11.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/forum/diy-surface-grinder-67127#post109600">Surface Grinder</a> <span> by <a href="https://www.homemadetools.net/builder/tonyfoale">tonyfoale</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/grinder'>grinder</a>, <a href='https://www.homemadetools.net/tag/surface'>surface</a> </div> </div> </div> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/forum/radius-gauge-reverse-engineering-70673#post123621"> <img src="/uploads/219843/homemade-radius-gauge-3.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/forum/radius-gauge-reverse-engineering-70673#post123621">Radius Gauge</a> <span> by <a href="https://www.homemadetools.net/builder/tonyfoale">tonyfoale</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/gauge'>gauge</a>, <a href='https://www.homemadetools.net/tag/radius'>radius</a> </div> </div> </div> </div>
Dec 28, 2018, 08:36 PM
GKK

Thanks. A tool I do not have, but sure could use.
Dec 29, 2018, 05:09 AM
scrdmgl

Hi Tony:
Could you please describe the principle behind this radius gauge? I have uses for it but I need to understand its application.

Thanks

Jorge
Dec 29, 2018, 08:08 AM
tonyfoale

Quote:

Originally Posted by scrdmgl

Hi Tony:
Could you please describe the principle behind this radius gauge? I have uses for it but I need to understand its application.
Jorge

Did you read the PDF file? I think that it is explained well in that. If that doesn't answer your needs then please ask a specific question and I'll try to help.
Dec 29, 2018, 04:00 PM
Toolmaker51

Quote:

Originally Posted by scrdmgl

Hi Tony:
Could you please describe the principle behind this radius gauge? I have uses for it but I need to understand its application.

Thanks

Jorge

Not to intercept Tony, with such a well developed tool and programming:
The dial indicator reads contact, plus or minus of plane established by the outboard 'feet'. Knowing distance between outboard feet [chord], and midpoint distance found by indicator [arc] boils down to representative geometry, or calculative trigonometry. It's all around us...roadways, bridges, ballistics, architecture, navigation, astronomy, surveying, even ocean towing by chain/ wire rope.
And recreating castings from machined billets.
Dec 30, 2018, 05:08 PM
Phantom89

Awesome👍👍 such a simple idea but very useful. And the cherry on top is the wooden case. Nice touch.
Dec 30, 2018, 07:35 PM
Mr.Pete

Thanks for this nice tool. I have to make one, its soo cool !
Dec 31, 2018, 06:14 AM
prm

Alternative formula

Quote:

Originally Posted by tonyfoale

I have just enhanced the software to allow calculation of the curve radius and centre coordinates when the XY coordinates of three points on a curve are known.
This is useful if you use the DRO on a milling machine to determine the coordinates of three points. This does not need the radius gauge described above.
The link to the software is the same as that in the PDF RadiusGauge.pdf

Tony,

I always read your articles with interest. As I had not used my brain over Christmas, I decided to work out the formula for the radius before reading the appendix.
I ended up with a different and, perhaps, a simpler formula: R=(s^2 + h^2) / 2*h
(where s is half the distance between the probes, h is the value on the indicator and, ^2 means 'squared')

I hope you won't mind if I also note that there are some typos in the pdf file : in the sections were you discuss errors in the indicator reading and errors in measuring the probe spacing, the radius value are not correct.

Regards,
Paul
Dec 31, 2018, 08:52 AM
tonyfoale

Quote:

Originally Posted by prm

Tony,

I always read your articles with interest. As I had not used my brain over Christmas, I decided to work out the formula for the radius before reading the appendix.
I ended up with a different and, perhaps, a simpler formula: R=(s^2 + h^2) / 2*h
(where s is half the distance between the probes, h is the value on the indicator and, ^2 means 'squared')

Paul,

I always like to find an easier way regards of where it comes from but I just don't follow your formula. Please show the full derivation. I assume that brackets could enclose the 2*h as (2*h) for clarity and that it is not ((s^2 + h^2) / 2)*h, to remove any ambiguity. In any case I am just not getting it, sometimes we get tunnel vision.

Quote:

Originally Posted by prm

I hope you won't mind if I also note that there are some typos in the pdf file : in the sections were you discuss errors in the indicator reading and errors in measuring the probe spacing, the radius value are not correct.

I never mind it when errors are pointed out. Thanks, I'll check it out later, I am on the wrong computer at the moment.
Jan 1, 2019, 03:50 AM
prm

1 Attachment(s)

Alternative ormula

Quote:

Originally Posted by tonyfoale

Paul,

I always like to find an easier way regards of where it comes from but I just don't follow your formula. Please show the full derivation. I assume that brackets could enclose the 2*h as (2*h) for clarity and that it is not ((s^2 + h^2) / 2)*h, to remove any ambiguity. In any case I am just not getting it, sometimes we get tunnel vision.

Tony,

I have produced a document with the derivation. It is very convenient that the r^2 terms cancels out and leaves a remarkably simple formula.

Cheers,
Paul
Jan 1, 2019, 06:27 AM
tonyfoale

Quote:

Originally Posted by prm

Tony,

I have produced a document with the derivation. It is very convenient that the r^2 terms cancels out and leaves a remarkably simple formula.

Cheers,
Paul

That's much better. At first I did think about going the (r-h) route but I thought that it would end up being more complex so I did it the way that I did.
I'll amend my pdf to show your derivation.
Jan 2, 2019, 03:49 PM
tonyfoale

Quote:

Originally Posted by prm

Tony,
I hope you won't mind if I also note that there are some typos in the pdf file : in the sections were you discuss errors in the indicator reading and errors in measuring the probe spacing, the radius value are not correct.

Regards,
Paul

I found the typo in the indicator reading section. I wrote 49.97 which should have been 4.97.
I can't find the error in the probe spacing part.
Mar 16, 2019, 12:25 AM
owen moore

There is a similar gauge used in optics. I think it is called a diopter gauge and it is used to measure the curvature of a lens or a mirror. Nice tool, Tony!
Mar 19, 2019, 08:18 AM
volodar

Slopes of perpendicular lines

Quote:

Originally Posted by tonyfoale

I have just enhanced the software to allow calculation of the curve radius and centre coordinates when the XY coordinates of three points on a curve are known.
This is useful if you use the DRO on a milling machine to determine the coordinates of three points. This does not need the radius gauge described above.
The link to the software is the same as that in the PDF RadiusGauge.pdf

Tony, a typo in the pdf´s Appendix:

¨Firstly we calculate the slope of the two lines AB and BC, then we bisect lines AB and BC with normal lines (shown in red), these will meet at the centre. The slopes of these two lines are obtained by multiplying the slopes of AB and BC by -1¨.

This holds true only for slopes of 1 or -1. Perpendicular lines have slopes that are negative reciprocals of each other.

In the diagram, by inspection, line segment AB has slope of about one half. AB´s red perpendicular bisector has slope about -2.
Mar 19, 2019, 08:29 AM
tonyfoale

Quote:

Originally Posted by volodar

Tony, a typo in the pdf´s Appendix:

¨Firstly we calculate the slope of the two lines AB and BC, then we bisect lines AB and BC with normal lines (shown in red), these will meet at the centre. The slopes of these two lines are obtained by multiplying the slopes of AB and BC by -1¨.

This holds true only for slopes of 1 or -1. Perpendicular lines have slopes that are negative reciprocals of each other.

Of course, you are correct. That was a stupid mistake.

PS. File has been fixed.