Router thicknessing-design & ruminations

[scooter]

Gday all, I'm redesigning my router thicknessing jig and welcome input from anyone with their thoughts.

I will be using my hitachi router and would like to plane up to say 350mm wide and up to 8ft long. Accurate movement of the router would enable the jig to also be used for long grooves, trenching across the grain, etc.

Had a crack at it a while back in order to plane some redgum, used 12mm threaded rod through the fence holes and 2 skis on my hitachi router running on a melamine sheet for a base. I screwed small battens to either side of the top of the melamine, approx 1" in from the edges to stop the whole rig moving sideways.

The redgum was secured to the melamine with hotmelt glue, set depth on the router (used a bowl cutting bit from carbitool) and started planing. Started on one edge, did a pass from end to end and back again, moved the router across an inch, end to end and back, and so on.

Shortcomings? Threaded rod sagged a little from the weight of the router; and melamine on a solid door across 2 supports wasn't dead flat. These two things resulted in a small degree of inaccuracy in the final surface. Also, moving the router across a set amount for each pass would be better simplified. Solid door, sawhorses, etc. - too much mucking around to setup and pack up.

I decided to base a new jig around an unused extension ladder I have. I thought the ladder would be light but rigid enough not to sag.

Chewing over options for supporting the router above the work, design for the "carriage" that incorporates a simple system for moving the router between passes..

Maybe a couple of short lengths of angle iron for rigidity?

For the lateral movement, I was thinking something along the lines of a "fast" thread such as the height adjuster used on the Triton saw table carriage.

I was envisaging making a pass, say rotating a handle one turn, making another pass, one turn, etc. Saw a fella using a fancy levelling jig with some sort of indexing action like this at last years WW show and it looked to make the process faster and more uniform.

Any and all ideas and suggestions welcome.

BTW, have searched and checked out some other jigs (some threads linked below) for reference.

http://www.woodworkforums.ubeaut.com.au/showthread.php?t=18747

http://www.woodworkforums.ubeaut.com.au/showthread.php?t=16032

http://www.woodworkforums.ubeaut.com.au/showthread.php?s=&threadid=4234

http://www.woodworkforums.ubeaut.com.au/showthread.php?t=5312

Ianab and Mick, I think you have made jigs, if you get a chance could you supply details/piccies on yours, and anyone else - all input welcomed.


Thanks & cheers...............Sean

[ian]

Sean

How much do you want to spend?

I can think of a fairly simple MDF jig, supported on the ladder's frame — assuming the ladder isn't bent longitudinally or twisted. The MDF would be faced with laminate and lipped eitehr side. The router would be supported on an inverted U that spanned the piece being flattened. In use you would wedge the stock to be flattened so it coundn't rock and just move the router arround until it didn't cut anymore. The small ridges between passes would be cleaned up with a smoothing plane.

I can draw a sketch if you interested.

Ian

[scooter]

Gday Ian, thanks for your response.

Yeah, I have the basic concept down, the main issue I guess is wanting to index the lateral movement instead of just moving it around. If there is a fair bit to do this becomes tedious.

I have wedged the stock to prevent rocking, but heavier cuts/lighter workpieces still required some form of work holding - without the mucking about of the hotmelt glue the toolmakers clamps made by Glen Bridger in one of the threads seem the best idea, I'm wanting something that clamps lower than the cutting plane so the workpiece can be planed right to the end.


Cheers...............Sean

[Schtoo]

Got an idea for you indexed passes, dunno if it will work well or not.

Take a lump of Lexan, make up a sub-base for your router of a set diameter size, say 143mm plus a smidge. If you have a 25mm bit, put markings every 25 mm, and a marking every 25 mm on the guide fence of your sled. Match up marks, make a pass, then rotate the base against the fence and match up marks again, you moved the bit 25mm in one direction. One full turn of the router is 450mm. Not super accurate, but it is simple and should be easy to implement until a better idea comes along.

May seem like a rambling there, I hope it makes some sense.

When you make up the base, try to avoid the trap of making it too heavy duty, which also means heavy and it will sag under it's own weight. Something you can adjust would be a good idea I would think.

Clamps below the surface, slots along the thing, sliding clamping block with a small spike in it. Clamps in from the side, and if you make them low profile enough, you can rout right over top of them without hitting them.

Just a mind dump. If it makes sense and you can use it, great. If not, I hope someone gets a laugh. ;)

[ian]

I have the basic concept down, the main issue I guess is wanting to index the lateral movement instead of just moving it around. If there is a fair bit to do this becomes tedious.

To me mucking about with a indexing arrangement seems to be more tedious than just moving the router arround.


... but heavier cuts/lighter workpieces still required some form of work holding - without the mucking about of the hotmelt glue the toolmakers clamps made by Glen Bridger in one of the threads seem the best idea, I'm wanting something that clamps lower than the cutting plane so the workpiece can be planed right to the end.

I can think of two options pinch dogs into the jig or Lee Valley "wonder dogs" teamed with ordinary bench dogs the other end/side.

Ian

[dai sensei]

...still required some form of work holding...something that clamps lower than the cutting plane so the workpiece can be planed right to the end..
As Ian says, how much do you want to spend. One way of clamping the work is vacuum clamps. I saw a good one at the working with wood show, but Gregory's also sells a similar version - http://www.gregmach.com/new_exclusive/vac_clamp.htm

[scooter]

Thanks for the input fellas.

Schtoo, happy to hear your mind dump, appreciate the ideas. Like the spike idea, I have some sail track that I could rebate into the melamine and make some small "dogs" that would slide in the track.

Ian, great idea with the wonder dogs, pics have been posted by others before on homemade jobbies that looked reasonably easy to make.

I've actually tried the random planing idea and got better results from indexing the passes. On the previous jig I'd make a pass, loosen the fence knobs, slide the router over a set amount, tighten the knobs then take another pass. Slow to explain but reasonably quick to do, just thinking on alternatives as the new sled won't be using the fence rods, and I was concerned the threaded rod would wear the fence holes.

Indexing does sounds unnecessarily complicated but in reality I'm just looking for some way to move a set amount each time without being too painstaking, doesn't have to be flash or technical.

Another reason, despite the bit I use (bowl bit 1 1/2" I think) being able to take a wide cut, I found the best results for the final pass on the redgum came with a cut of no more than 1/4". This meant a lot of passes for the best results.

Neil, trying to do it without getting too fiddly so would probably prefer mechanical clamping over the vacuum clamping. Thank you for putting it up tho' mate.

Welcoming further ideas and input.............cheers.............Sean

[Stubchain]

Hi Scooter,

You saw my basic router planer jig. I though this was a fairly inexpensive option with the versitility to do almost anything. The boards in the photo were 450 x 600 and were planed to under .5mm difference all over.

To hold the panels in place I just used some panel pins in the top of the bench. I also pinned some small peices in the sides of the boards to stop them rocking. I only had a 1/2 inch bit, so they took a while. I also toyed with trying to cut in straight lines using various bits and peices, in the end I just drew parallel lines on the board as a guide and did it by eye. It works very well. With the set up I have I can plane boards about 750 wide by an infinite length.

[Ianab]

Hi Scooter



This is my 'jig'

http://www.woodworkforums.ubeaut.com.au/showthread.php?t=17344

It's really just a simple plywood frame to mount the router on the side of my Peterson sawmill. It lets me use the rails / wheels / height adjust and side adjust of the mill to move the router.

Works well.

I could only find a flat router bit locally, and that leaves slight lines and can tearout if the grain is weird. I thing a curved edge / flat bottom bit would be better.

Without having the mill already, it would be overkill for a router jig though:o , but maybe it will give you some ideas

Cheers

Ian