Mini skill saw and lathe on my PRT

[robert_cheal]

Its been a while since I have had time to post any thing.
My low budget application worked on some cedar turnings that I needed to replicate from a porch of a Victorian era home

The lathe was a $99 laid on its side and a mounting bracket made of 3/4" BB for the 4" mini skill saw I bought at Lowes.

Here are some links on Youtube:


http://www.youtube.com/watch?v=ni4pzwX1xek&context=C3f73ce7ADOEgsToPDskLFKoEWmInhI_kDDsJ15PI-

http://www.youtube.com/watch?v=Jp7TO54XU9k&feature=youtu.be


It took more time than it was worth but I might use it again and that would on mean about 15 minutes to set it up again. The cedar was soft and fuzzy but sanded up ok. I have not tried any other woods yet but I think they would probably work better.

[ironsides]

Robert,

That is a very impressive setup.
What software program did you use to generate the cutting file?
What was the geometry of the saw tooth?

George D Kelly

[robert_cheal]

I created the part profile in AutoCad and the offsets of the tool path at .05" roughing and .025" for finishing. Then I used Vcarve to create the part file. I can't remember what the saw blade width (about .075") was but on the final pass I factored the blade with (not on center) but as the leading edge approaching and following the contour. I modified the finished path to compensate for the blade thickness other wise it would alter the final cut and not match what I had drawn. Not sure if I am explaining it very well.

[myxpykalix]

Robert,
That is very clever. I have seen guys use a circular saw on a Legacy Ornamental mill with a template to do this type of thing manually and I have seen those machine that make baseball bats and other things where they use a stationary flat type of cutter.

I guess the tricky part of your setup is to have the apex of the curve of your blade at the center of the material because it was a curved blade?

At that point it is just a matter of running a toolpath which is the profile of the shape you want right? How do you figure your offset?
Very cool:cool:

[robert_cheal]

Jack,

When doing test cuts I realized that final pass did not match the drawing of the part due to width of the blade. So I drew straight line perpendicular to profile and then offset lines one half the blade width all along the profile. Then I created and linked up a new stepped profile line than would maintain the cutting edge of the blade to follow the intended finished profile both when approaching a radius and retreating from it. I could probably explain this better but I don't seem to be doing it right now. If I can find my drawing it would be easier.

Robert

[robtown]

Definitely an A for effort, but I don't know if I'd try with harder woods. You can see the sawblade flex, circular saws aren't really made for lateral movement like that.

[robert_cheal]

When I started this little adventure I wondered how long the skill saw would hold up or if it would get me through the project. About 10 runs of what is shown in each video and 10-15 minutes per run x 20+ . Cheap skill saws and grinders even when new sound like the bearing are going out. I checked the saw for excessive heat and it seemed be holding up I am sure that I could toast it with a little persistence. The softer grain of cedar was a little frayed before sanding I might be willing to try some alder or mahogany but don't have any projects in mind at present.

I was trying to match existing details for the turnings and traced over photos of the original porch details in CAD. When it came time to build the project I had to either buy non matching stock turnings or send my drawings out and have them duplicated in cedar. Then for some crazy reason I decided to torment myself with this solution.