Thread: Using 3 1/2 inch raised panel bits

Hi Chook,
Looks like you're up early like me.............that goodness for light beer! (I had to drive home last night anyway)

The speed of the bit is the first consideration. Slow the router right down so that the tips of a wide cutter like that aren't going too fast. The wider the cutter, the slower the speed. (there's been lots of discussion in here about router bit speeds and a search will find some of those threads)

Make the gap between the original fences wide enough for the bit to pass through, then make a new fence from some mdf which you can simply screw or clamp on to the face of existing fence. Make it in one piece, going right across both of the Triton supplied fences and have it flush with the table top. Turn on the router and slowly move the fence out over the panel cutter so that it cuts a slot in the mdf. That way, you have the new fence completely surrounding the cutter, except of course where it has cut through. The fence will be immediatetly above the tip of the cutter and so your work-piece will be fully supported as it passes over the cutter.
When cutting your door, do this in small increments, adjusting the fence backwards to expose more of the cutter each pass. Don't attempt to take the full width off in one pass.
I think, by having the work-piece completely supported by the mdf fence, you should be working safely. The bit will be under the panel as it cuts. Have a go with some scrap timber first !

I hope this makes sense...........it's difficult to describe.

I had the same problem with a big router bit in the Triton.

I removed the insert and filed off some of the table so the bit would spin without fouling, turning the bit by hand of course!! :eek:
The bit has to be inserted above the table for this to work.
One concern I had at the time was, what would happen if the router decided to drop down, there would be carbide and steel sprayed everywhere.

Al

Originally Posted by ozwinner

One concern I had at the time was, what would happen if the router decided to drop down, there would be carbide and steel sprayed everywhere.

Al

That will give me something comforting :eek: to think about when I try to get to sleep tonight!


Gumby,
I will try it. As for being up early, ever since I was a boy I have beaten the sun up. I cannot train my neighbors to get used to the sound of a thicknesser at 4.45 am otherwise I could really have some fun in the mornings.

Hi Chook,Gumby has covered all the salient points that really should be adhered to,however you did not state whether you had a variable speed router but we assume that you have and if so then Gumby's advice is pertinant.

If however you have a fixed speed router then I would in no way attempt using a 3 1/2" horizontal router bit.

Do a search in the forums using the search string "router speed" and I think you'll find it will relate to about 8000-10,000rpm on you router to employ that bit.

Another alternative if worried about metal shear if your router should drop(unlikely if you have all precautions)is to use a verticle panel raising bit able to be used with higher speed as well as a (minimum 12") fence for support.
I use a piece of pine 12" board as a support fence.

Good luck & take care.
Cheers

I will be using a triton router at about 8 to 10 thousand rpm.

It has been suggested that I make a false fence from MDF and push this fence through the router to provide some level of protection. Then to avoid taking to much off in one pass I am then to move the fence back taking away more material each time. Now I can see how that will work on the current set of doors which I am going to make. They are rectangular.

BUT...

The cutter has a pilot bearing so that I can make raised panels in arched doors. In this case I assume that this method will not work.

Also the cutter I have has a back cutter to cut the raised panel on one side and a rebate on the back of the panel also, in a single pass.

I am very cautious when using machinery, and especially so here.

HI i have used them cutters before and had the same problems. In regards to the hole in the table being to small i just raised the bit just above the table and made a false bottom with a piece of mdf. And the fence, I just cut the hole for the cutter as close as i could with the jigsaw and a file.I made a full sized door so my panels required at least 3 passes on a triton router running on the slowest rpms it also pays to make the last past a small as possible to get the best finish.Also be prepared for the amount of shavings and dust as my vac could not keep up and i had to unhook it.

Instead of cutting in increments by moving the false fence back a step at a time, a better technique, particularly with bearing bits, is to raise the bit a step at a time. With my table router set up (and I guess, most others) the hole is big enough so this is no problem. In your case what are your options?

I am personally quite uncomfortable for safety reasons with the idea of a router bit, bigger then the hole, spinning above the table. In any case, this forces you to cut full depth and more, which is probably not what you want. And let's say the bit is (just) 1 mm above the table ... how does this 1mm of timber thickness get cut?

My recommendation, assuming you can't cut a bigger hole for the bit to pass through, is this: (will depend on how far above the table the bit can extend).

Make a false floor to your table (as well as a false fence).

1) Get a piece of melamine-coated MDF the same dimensions as your table and thick enough to house the full thickness of the cutter. Drill a 15mm diameter hole in it for the bearing to pass through.

2) Initially clamp this false floor above the table (using some spacers) and raise the bit through the MDF. You now have a zero clearance hole through wich to work.

3) Lower the bit. Clamp the MDF flush onto your table positioned over the hole you just made.

4) Make a new fence the way Gumby described but you won't be able to attach it to your existing fence (and you don't need to because it doesn't need to move). Clamp it also to your table (you might need some square blocks to screw and clamp to) . The fence stays fixed, aligned with the bearing on your panel-raising bit.

5) Start work --- raising the bit in small increments, until the panel edge is the right thickness. With this technique, I often raise a little of the panel on the back side too (or first).

I don't like the term "false" fence or "false" floor -- I have lots of different fences and floors that I make and attach to my router table for special purposes - particularly if I'm working with really small pieces ... then I call them "zero-clearance" fences/Floor or maybe the term could be sub-fence if they are attached to your main fence.

Hope this helps

Qw