Learning Curves

Short and steep!

Despite having some (limited) experience with CNC routers, I hadn’t tried parts fabrication before – cutting out one of the patterns as listed in my previous post.

The website provides next to no instruction on how to use the patterns, so I was left either watching the 98 or so minute ‘tutorial’ video that someone had made, which although useful for info, was very difficult to watch through, so I skipped about a bit to try to glean some answers.

Suck and See.

Biting the bullet is sometimes a faster learning curve, so long as nothing gets damaged in the process!

I created a path for one of the simpler dinosaurs – using a 1/4″ upcut solid carbide router bit from Toolstoday.com, created a few tabs so parts would remain in place once cut out, and sent it over to the CNC computer.

Some things to note.  When the program says something about it being outside of the soft limits, what it really means is that somewhere around the circumference of the design, you are going to ask the router to move further than it can physically achieve.  While that makes sense in hindsight, you can find yourself trying to work out why the program just wont run, quite fruitlessly.  Note to self – don’t deactivate the soft limits!

Somehow, even though I had set what the full depth of the job was meant to be, it only did one pass, rather than the two or three that would be needed to cut all the way through.  Have to look at what I missed there!  That is why we test these things to see how they work!

Where it did cut all the way through (I reset the Z height so it would achieve a full depth, and ran the program again – effectively manually causing it to cut through in two steps), the tabs I had made were no-where near large enough, and parts were coming loose and impacting the cutter.  Using an upcut bit exasperated the issue, as it was trying to lift the pieces out as well.

Four clamps on the board, one in each corner is not enough, especially as the board becomes riddled with cuts.  A vacuum table will be a significant improvement, when I get around to making one.

And a 1/4″ bit is too large a diameter for a 6mm thick design – none of the slots needed to join pieces together were cut, so I need some smaller diameter router bits for this sort of work.

Well, nothing was damaged in the process, and plenty of information was gathered to make the next attempt more successful.  No matter how sophisticated the equipment, there is always a learning curve on how to best utilise it.  Of course that is part of the fun!

Item Duplication on the Torque

There are a number of different ways of duplicating a pattern or item in woodworking.  A common method is to screw a pattern to the timber, use a jigsaw, scrollsaw or bandsaw to rough it out, then revert to a pattern copying bit on the router table.  This technique works well, but does have its difficulties, including keeping the template attached to the workpiece (or separating it afterwards, depending on just how strong the carpet tape is!)

The Torque Workcentre offers a couple of unique techniques and solutions to the problem.  The one addressed here is using a pre-cut track to follow a captive pin.  It has consistent results, and is difficult to get wrong.

Step one is to produce the desired track.  You could cut it freehand (and in some cases that would work), but here we want an exact replica of an existing component – in the case a racing kangaroo.

Mount the item to be copied to the underside of the (blank) pattern

Take the object you want to duplicate and fix it to a board.  This may be an existing item, or one you have made up for the task out of MDF for example.  Add a couple of equally thick boards on either side so the pattern has no tendency to rock.  Flip the board over so the original is to the bottom.

Mounting the router

Mount a router bit of equal diameter to the captive pin diameter (which can be seen in the first photo, already mounted in the table)

It is worth noting here the ease for removing and replacing the router, including in this case a Triton 2400W.  The mount is different to that for Makita and Hitashi, but the actual attachment method is the same.  The router plunge base is removed (which is very easy), and the router mounts directly onto the Torque by using the plunge mount shafts.  It was one of the first things that made me sit up and pay attention to the whole Torque Workcentre – using the plunge mount, and especially using the plunge lock to secure the router onto the Torque was such a simple and clever solution that I was suitably impressed (not always an easy thing), and wondered what other clever ingenious things went into the TWC.  I’m a sucker for good engineering.

The router is mounted back into the Torque, and set so the router bit is directly above the copy pin in the table, and its position fixed (there is a lock for both the X and Y axis).

Creating the track

Plunge the router lightly into the surface of the blank pattern, and by holding the original (underneath) directly up against the pin carefully create a channel all the way around.  When you have gotten around first time it gets a lot easier, as you then know where the pattern is as you rout deeper.  Repeat until you have a track that is deeper than the length of the copy pin.  This is the captive track that will allow copy after copy of the part.

Depth Setting

Once you are ready to start creating copies, attach the blank on the top side of the pattern (you can screw it down, or use clamps (I use the Walko clamps on the jig))  With the router mounted directly above the copy pin and a router bit that matches the pin diameter (and the width of the track), plunge the router (turned off) so it goes deep enough to pass all the way through the blank and just into the top of the pattern.  Set the plunge lock to this depth.

First pass

Mount the pattern onto the pin, turn on the router and lightly plunge into the blank.  Run the pattern all the way around (you can see here that I’ve take the photo before completing the kangaroo tail).  This gives you a track to be able to follow visually when you plunge the router deeper for subsequent passes.  Plunge the router deeper and run around the pattern again.  Rinse and repeat until you are almost all the way through.

Completed part copy

With the final pass, the new part can be lifted free – a perfect copy of the original.  Repeat the steps to create part after identical part.  The track can be kept so the part can be made any time in the future.  This technique can be used for all sorts of things, including furniture, inlays, and definitely toys!  You could easily set up a little production run in your workshop to create toy after toy (wooden toys are some of the best presents – how many times have you seen an antique plastic toy?! (yeah, I know I’m being a bit facetious, but you know what I mean – plastic toys just don’t last, wooden toys get handed down from generation to generation)).  Fighting back against the plastic toy generation(s)!!

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