Thread: Wide Slab Router Sled

I've made something similar in the past (1500 wide) and it was okay until the router bit hit a knot or caught the grain. If this happens and you only have the 50mm horizontal of the angle resisting the force, you can end up with the router deflecting enough that the bit gouges and makes a mess. The mess gets worse the bigger the diameter of the bit is.

You really need some lateral thickness to stop this type of deflection and twisting of the angle, so using some 19mm mdf as the verticals, or some aluminium SHS or RHS would be better.

I also found that my hitachi router didn't like rubbing against the aluminium and would jag from time to time. My list of things to try and avoid this includes:
1. using a ptfe tape (on the router plate vertical edges) - the kind used for non-marking furniture feet;
2. attaching some mdf/timber/abs edging on the rubbing surface;
3. making a thin nylon, ptfe, or uhmwpe slider to rub against the aluminium; or
4. avoiding all of that and using the router's side fence passages to pass shafts through that have a roller at each end so that you can use a c-channel instead of the angle and have nothing between the base plate and the work piece.

Each of these have their benefits and problems. With the last option, industrial rollers are available, but tend to be expensive as they have high load capabilities. There is no reason that you can't just use a sealed ball bearing on a piece of shaft/threaded bar and only pay a couple of dollars each.

Best of luck with it, I'll be interested to see what you end up doing. I'll probably be looking at this issue again in the next couple of months too.

Thanks SPF, all good thoughts. I had thought of either 19mm pine or 19mm MDF for the vertical outside of the 50 x 50 angle for controlling any sag but thought that a 50 x 3 alloy plate would have better vertical deflection. If I read your post correctly, you seem to suggest the MDF as better, am I correct there ?

For the router face bearing surface, I was thinking of silicon spray ( have some in the cupboard ) then some of the slippery tapes etc.

As always, the hasten slowly and shallow with the planing bit rules....

BFN

UPO

UPO, sorry I could have made that clearer. Vertically, the aluminium is going to be stiffer as you suggested, but it will have no stiffness horizontally. The problem I had was that when the router caught it effectively separated the two pieces of angle and the router then ricochets between them and causes them to twist.

So what I was saying was that you need to have some stiffness horizontally as well as vertically - the aluminium angle is not enough.

OK - had a second closer read of your post & I had failed with the lateral implication - now I think that would be pretty much a guaranteed weakness and as you suggest an RHS rather than a horizontal plate would probably be better - any mech engineering types out there ???

With the current sled, making it a little longer ( 40mm ) to suit the modification I made to my bench - I added another stringer to the back side to make clamping easier - still wont sort the situation if I need to go beyond about 600mm routing length as I am not changing the actual router rails / bed length.

Thanks for your clarification, appreciated

Regards

Richard

Hopefully I can attach a photo of my current sled - made from this photo which is from a post on the Lumberjocks web site - BTW, a very good web site .

The sled is very to change clearance heights for different slab thickness.

Router Sled - LumberJocks.jpg

Thanks Lumberjocks for great web site

Richard