My latest project – Ruler Marking Gauges (RMG)
The idea of refining available designs to create what I call my multi-generational RMG was brought into focus by the vast quantity of YouTube videos on the subject. While almost all of those videos do lead towards the creation of a useable gauge, almost all of them have some shortcomings which I thought I might address. There are a few videos that describe how you might make one of these items that you would feel proud enough of to pass it along to your children, but even those had some weaknesses in their design.
So, my quest for the perfect RMG began. After several prototypes and failures of either design or execution, I have arrived at something I can realistically think of as still being used 100 years or more from now. Is my design perfect? Perhaps close – but I am hoping some of you might suggest ways the design can be improved.
The detailed process is fully described in a Word document I will attach so anyone with time to spare as well as interest can read through that 4 or 5 page document. Meanwhile – the images I have included will convey much of what I have included in the design. A couple of things are not really evident from the photos though…
First is the mechanism that holds the ruler in place where you want it. For that, I have included a captive disc of bronze – about 2mm thick. The thumbscrew tightens against the bronze disc and that in turn is forced against the ruler. Should last a long time I think – and the ruler is not marked at all because the bronze is softer than the steel. Not much – but enough.
The second is the insert that the thumbscrew turns into is also made from bronze. It has a lip on what I think of as the bottom and is glued in place. All of the force applied when tightening the thumbscrew solidly holds the insert tightly so it should never loosen. Thumbscrew is M6 brass.
Final point is that the channel the ruler slides in is made from brass, precision machined on my milling machine (and very closely matched to each individual ruler). I am not totally convinced that brass is ideal here and I just received my order of sheet bronze so the next one I make will use that. Bronze should outlast brass in this application by a large factor is my thought. I did make the smallest example using part of an old bronze hinge I had here for decades, but that only works with the smaller sizes of the RMGs.
I am hoping most of you will be a little forgiving because these gauges do use a lot of wood. Carefully chosen of course. But most of the project involves metal and machining of various sorts, so I thought that overall, it was of enough interest that I should post it here.
The idea of refining available designs to create what I call my multi-generational RMG was brought into focus by the vast quantity of YouTube videos on the subject. While almost all of those videos do lead towards the creation of a useable gauge, almost all of them have some shortcomings which I thought I might address. There are a few videos that describe how you might make one of these items that you would feel proud enough of to pass it along to your children, but even those had some weaknesses in their design.
So, my quest for the perfect RMG began. After several prototypes and failures of either design or execution, I have arrived at something I can realistically think of as still being used 100 years or more from now. Is my design perfect? Perhaps close – but I am hoping some of you might suggest ways the design can be improved.
The detailed process is fully described in a Word document I will attach so anyone with time to spare as well as interest can read through that 4 or 5 page document. Meanwhile – the images I have included will convey much of what I have included in the design. A couple of things are not really evident from the photos though…
First is the mechanism that holds the ruler in place where you want it. For that, I have included a captive disc of bronze – about 2mm thick. The thumbscrew tightens against the bronze disc and that in turn is forced against the ruler. Should last a long time I think – and the ruler is not marked at all because the bronze is softer than the steel. Not much – but enough.
The second is the insert that the thumbscrew turns into is also made from bronze. It has a lip on what I think of as the bottom and is glued in place. All of the force applied when tightening the thumbscrew solidly holds the insert tightly so it should never loosen. Thumbscrew is M6 brass.
Final point is that the channel the ruler slides in is made from brass, precision machined on my milling machine (and very closely matched to each individual ruler). I am not totally convinced that brass is ideal here and I just received my order of sheet bronze so the next one I make will use that. Bronze should outlast brass in this application by a large factor is my thought. I did make the smallest example using part of an old bronze hinge I had here for decades, but that only works with the smaller sizes of the RMGs.
I am hoping most of you will be a little forgiving because these gauges do use a lot of wood. Carefully chosen of course. But most of the project involves metal and machining of various sorts, so I thought that overall, it was of enough interest that I should post it here.
Attachments
-
Close up of ruler guide.JPG -
Custom plywood version of RMD .jpeg -
End view of Ebony wood version.JPG -
First prototype with commercial insert.jpeg -
Inside look at brass ruler guide.jpeg -
Small RMG showing bronze guide.jpg -
Some of the hardware used for RMGs.JPG -
Top view of Ebony wood version.JPG -
Ruler Measuring Gauge.pdf
