Overhead router system

Davecam48

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Since my forced retirement about 5 weeks ago I've been making considerable amounts of sawdust, and while I'm working on a concept guitar project, I built a pin rout system using my table router which I posted here, and used it to make this jig.
Wishing that I had a bit more control and accuracy the overhead router looked the way to go, so set about designing, (nothing on paper, all in the noggin) an adjustable overhead system, which I must say even surprises me with how well it works. The lifting/ lowering mechanism is made entirely out of 20mm ply and consists of two sliding rails mounted on a plate to which a block of maple is attached with a "T" nut at each end and the rails run between two ply guides. A 5/16th threaded rod through each T and a wheel on top which runs in a fixed plate and Bob's your uncle. The sliding plate is held in position by a bracket each side of the back board and a block with a router sized hole cut in half and a couple of wing nuts and it's all done.
The most difficult thing which actually took more time than building the frame and mechanism was the precision depth gauge in Imperial and Metric and, as most things, very simple in the end. An aluminium ruler with both denominations on it, the Imperial side was cut off on the bandsaw and mounted against the Metric scale. WHY ?? Because rulers all start at zero on the left hand side, well the ones I could find, and we need both zeros together so we can zero both scales with the same indicator.

To rout to a precise depth I put the template over the pin and wind down the bit until it just contacts the surface, move the scale to exactly zero on the red bar, this is your base line. Slide the rule down the required depth, say 3mm, and then while holding the job firmly switch on the router and wind down the mechanism until exactly on the zero line again and you're routing @ 3mm depth.

In actual fact a 3mm route measured 3.05 on the digital calipers sooooo!

As an exercise just to see how well it worked, today I knocked a very rough template and made the gear in the pix ( which I dedicate to Kwerk! ) and the whole exercise took about 1.5 hours using a 1/4" bit. Taught me a lesson on how you MUST make excellent templates because any errors appear in the job. I think this would cut out a solid body in about 20 mins. Doing the gear cut I only went down in 3mm increments which left some fine tooling marks but they rub out no problems and if it was a serious job more care would have been taken. Anyway Gents and Ladies I'll post a few pix for you. DC
 

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Davecam48

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Thanks Phil. Yeah I'm really pleased with it and there is zero play in the whole assembly or at the router bit which makes it so accurate. The pin is mounted in the table opening for the bottom "big" router and I have about 18" access either side of the bit so can do more than make small stuff. All I have to do now is find things to make with it. Making the gear today I had more fun than when I discovered girls and beer, well maybe not.

You have nothing to live down with the gear thing mate, it was a great and unique concept. Did you receive the prize yet?
 

Engraver-60

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I don't see your template. And yes, it looks like a manually operated Z-axis for a cnc machine. Next hook up a stepper motor to the top and you'll have a cnc (1-axis). Very cool design and nice work.
 

Bolide

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Very cool. Maybe you could replace the height adjusting wheel with that fine looking gear.

That immediately caught my eye as well, and reminded me of the story of John Harrison, the clockmaker who succesfully beat the challenge to find a satisfactory method of determining longitude.


There are large outdoor clocks (on churches and such) which Harrison built in his youth where the only metal parts are the sash weights which are still working today (with fairly remarkable accuracy), and have only been cleaned a couple of times in the last couple of centuries. He used lignum vitae for the hubs (for its self lubricating properties) and teeth (for its toughness) with a different, lighter, hardwood of higher tensile strength for the webs of his gears.

http://www.amazon.com/Longitude-Gen...=sr_1_4?s=books&ie=UTF8&qid=1314281600&sr=1-4

Yes! That is one fine looking gear :D
 

Davecam48

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Very cool. Maybe you could replace the height adjusting wheel with that fine looking gear.

Thanks Jack. The really cool thing about the mechanism is that you could turn it upside down and fit under a table and it becomes a router lift but I already have a $5 scissor jack doing that.

The gear was actually cut with the intention of using it as the top wheel with a smaller one meshed in for fine adjustment and may end up there today, but the thread on the rod takes 18 turns for an inch of travel so it is fine enough. The original wheel was just the bit left over after a hole was removed from around it.
 

Davecam48

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To follow on from Jack's suggestion, this morning I pulled off the old MDF wheel and fitted the cog. To me it looks at home there, and easier to twirl, thanks Jack.
 

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kwerk

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excellent Dave.. Reminds me of that open source project going on at the moment to make 3D printers that can replicate themselves!
 




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