coping sled plans?

[bdeditch]

As the title says, can anyone direct to some plans to build a coping sled for a router? Thanks in advance

[LRod]

Slab o' plastic (about ¼" thick-a lexan type--acrylic, I think--would be better than a brittle plastic, like polystyrene--I'm not too good on plastics). You could also use Baltic birch.

Stick o' UHMW for a fence. Screw to plastic. Make sure it is absolutely square to the side of the sled that will bear against the router table fence. You could also use Baltic birch.

Toggle clamp. De-Sta-Co is the original, I think, but there are others. Screw to UHMW.

Has to be just about the easiest accessory to build. No need for plans.

[George]

ANY square block that can ride against the router fence will do, of course. Nice thing about blocks is that they also gain the profile of the cut on the first pass, and aid in preventing chipout on subsequent. You can do the holding if you like, after adhering a bit of sandpaper to the edge of the block. Don't put it where the bit's going, obviously!

You can make full rig for a a set of hold-downs if you want, then elevate the bit to clear the base of the sled. Just make sure, on anything you make, that you allow for a replaceable backer to get best advantage.

Start here and work toward your design.

That way you'll have a miter fence, too.

[chuck]

The sled's fence needs to be perpendicular to the miter gauge slot if one is being used. Since the miter gauge slot and the router table fence are almost never used together, and since the router table fence is usually adjustable, it could be a coincidence if the fence and the slot are ever parallel.

If there is no miter slot, it might be better to guide the sled with the front edge of the router table (if it is suitable) than with the fence. Once the sled fence is made perpendicular to the table front face, it will always be so. When an adjustable fence is used, perpendicularity of the sled fence to the router table fence has to be checked/adjusted whenever the fence is adjusted.

However, if a miter gauge slot is available, it is usually much better that a coping sled be guided by it, rather than by the router table fence. The main reason is that the cutter is prevented from pushing the work away, which is often seen in coping operations.

Sorry to be so wordy.

Chuck

LRod wrote:

[LRod]

[top posted for your convenience]

You must have missed the other thread. My counsel is not to have a miter slot, and the need for the sled is based on that premise. One of the arguments against the slot is the need for parallelism between it and the fence. If there is no slot there is no parallism issue.

By counseling for the front edge as the guide you bring back the issue of parallelism. Why complicate things? If the fence is the sole guiding part of the table you never have to worry about any other guiding apparatus' relationship to it.

Your assertion of needing to "adjust" the fence must be in reference to a split, jointer type of fence (one used when a full profile is routed off the material). In reality, only a small percentage of operations need that capability and having a split fence for all the rest is a waste of engineering and time wasted on a fussy apparatus.

This is likely to start up another thread on router table design philosophy.

[chuck]

Sorry. I did miss the earlier thread. I still do not understand the need for parallelism between the miter slot and the fence. Just as with a table saw, it is most unusual to use both the fence and the miter slot simultaneously (unless the fence is used as a cutoff stop a la Unifence, rather than as a fence). Can you provide an example of where this parallelism is necessary or advisable?

If there is no slot there is no parallism issue.

And even with a slot there should be none.

Not complicated at all. The sled fence must be perpendicular to whatever guides the sled in its travel. That can be the router table fence, the miter slot, or the edge of the router table. But only two of those options will never change. And of course, the orientation of the sled fence relative to sled travel is advisedly fixed also.

Well, a split type of fence would present a problem. But many non-split router table fences can be adjusted to make various angles with respect to the sides of the router table. The angle such a fence makes with either the front of the table or the miter slot is 180 degrees only by coincidence, unless it is set that way. It is a little disturbing that my comment has been turned into advocacy for split fences!

That might be useful, unless, of course, the final words have already been spoken.

Actually, I made no recommendations with regard to router table design or fence design. My comments were directed at the OP's request for info on coping sled design, taking cognizance of the overwhelming preponderance of commercial router tables with miter slots.

Keep in mind that some of us might use coping sleds guided be either the miter slot or the front of the table, your apparent counsel to the contrary notwithstanding. In those cases, making the sled fence perpendicular to the router table fence is inappropriate advice for the reasons I have offered.

I also advised that, if available, a mitre slot-guided coping sled offers the advantage of preventing movement of the work away from the cutter. While a clamp on the sled discourages movement of the work relative to the sled's fence, it does nothing to prevent movement of the sled itself away from the router table fence. The operator must provide this function with his hands. I've found it to be far more pleasant to cope on either a shaper or a router table when the only control I had to provide was the feed rate and a slight downward force on the sled.

It can be left to the reader to judge whether that is persuasive.

Thanks,

Chuck