Overhead Routing with Fence

[bainin]

Hey all - moving along on my first project and considering using the
overhead router mode to roundover some boards.

Most of the images in the manuals show a fence setup which places the fence
behind the bit with feed from left to right.

However-my boards are a bit too wide to setup this way, so I am considering putting the fence in front of the bit for more table space.

The question is - as configured in the picture, is the feed direction shown on the tape the proper feed direction ?

I've tried to indicate bit rotation as well-though its hard to see on the 2nd piece of yellow tape

Is there a better way to configure the setup for this operation ?

climbcut.jpg (71.38 KiB) Viewed 28812 times

It feels reasonable on a test board-though i haven't tried feeding from the other side.

About midway in this thread-BuckeyeDennis showed diagrams which would indicate that my setup is ok, but Ive confused myself by moving the fence to the opposite side

https://shopsmith.com/ss_forum/beginnin ... 2-s20.html



Thank you

[rjent]

Does your bit have a bearing? If so, I wouldn't use a fence. What you show there is wrong IMHO. Look into getting a router fence, or making a fence with t-nuts. I have both and use both. Lots of ways of cat skinning, but I don't like what you are showing in your picture.

JMHO

[bainin]

Thanks Dick -

Yes the bit does have a wheel bearing. Of course the wood is too thin for it to be much use unless I tape my piece onto a larger board-which I intend to do.

Are you suggesting just running it without any fence or featherboards ?

You are right though- I do need to make up a t-nut fence.

Regards

[BuckeyeDennis]

Trapping a workpiece between a router bit and a fence to make an edge cut is a risky proposition, IMHO. Even if you feed in the correct direction.

A much safer way to do it is to bury the router bit in an auxiliary fence facing. See figure 10-5 and 10-6, and the accompanying description, in the following link:

https://www.shopsmith.com/academy/routing/index.htm

Or just use the SS shaper fence, if you have one.

[bainin]

I do have a shaper fence..havent looked at it yet. Based on the link you sent, would this be the preferable configuration for a shaper fence process?

shaper-fence.JPG (61.29 KiB) Viewed 28786 times

[rjent]

Yes, absolutely! You don't want to "trap" or bind a workpiece between a fence and a cutter.
IIUC, if you want to do a roundover on the edge, put your PP and the Mark 7 in undertable mode, extend the bit to the right height and use the bearing to maintain the depth, OR, using the fence like in your image, except have the bit extending up through the table from underneath for the appropriate cut.
If you are using a MV, then your image is correct and carry on ...

I do have a shaper fence..havent looked at it yet. Based on the link you sent, would this be the preferable configuration for a shaper fence process?

shaper-fence.JPG

[bainin]

One thing i noticed scanning thru the routing and shaping sections of the link above, it seems like for most overhead routing conditions shown that require a featherboard, the featherboard is usually setup to limit horizontal displacement.

Whereas in shaping mode, the featherboards tend to be limiting vertical movement.

Does a router bit tend to cause horizontal movement and a shaper bit tend to cause vertical movement?

[BuckeyeDennis]

I’d say it depends on the shape of the bit. A straight bit will try to move the workpiece horizontally, but not vertically. A panel-raising bit will try to move it in both dimensions.

This may be just a quibble about terminology, but a featherboard’s job is not to “limit” motion ... it’s job is to eliminate motion toward the featherboard. It does this by applying a preload force, greater than whatever the cutting tool might generate, that forces the workpiece to stay in contact with a fence or table opposite the featherboard.

My shaper fence came with a handy-dandy quill-mounted featherboard, which I tend to use it even when it’s not strictly necessary. That may be why you saw the vertical featherboard so often in shaper setups. The better you can control your workpiece, the better the chance of getting a clean straight cut.

At the link below, there’s a shaper setup where I thought it wise to use both horizontal and vertical featherboards on the same setup.

http://www.shopsmith.com/ss_forum/viewt ... 67#p249267

[sehast]

I was of the same opinion about not trapping a work piece between the fence and the bit but I just recently watched a Woodsmith video that promotes that very technique. They call it ripping with a table router. Caveats are only use a straight or spiral bit and take very light cuts.
Here is the link to the video but I don't know if it is accessible to non-members.

https://www.woodsmithvideoedition.com/e ... oplay=true