# Router flattening jig for small stock, is it safe?



## Plane (Sep 19, 2021)

Hello, 

Router slab jigs are commonly used to flatten, and make plane slabs too large for a planer. However I am looking to determine if it is a safe technique on much smaller stock. 

The reason? I don't have a planer, they are expensive, as well as a small basement shop next to a HVAC system really limits my options.

The boards I am dealing with are in the range of:
Thick: 1/2 inch
Width: 2 5/8 inch up to 10 inches
Length: 16 1/2 inches up to 42 inches

From an initial look at the boards it seems that I may have to take off an 1/16th or 1/8th off of both sides in the typical cases. The worst being possibly 3/16th. 

Clamping Option 1:
Screw scrap next to all 4 side to keep the board from sliding. I could also use double sided tape with this method to prevent lifting since the pieces are so light and there would not be any downward force. Just the tight fit between the boards on each side.

For such small pieces, does this seem like enough clamping to keep the pieces in place? Is lifting out a concern?

Clamping option 2:
Sacrifice some material at each end of the boards to hold down the board. Could also use side Clamping like in option 1 to prevent sideways movement. This would give a better downward hold, at the expense of material. 

Optional step for worst boards:
If thickness is a concern, I have considered flattening one face of 2 pieces, then gluing them together to get a thicker piece. This allows the process to start over again but with a thicker (and hopefully safer matterial).

Is this a safe process/operation for smaller boards? What do you think the smallest limit this technique would still be safe? 

Reminder that I recognize that a planer would be great for this, however I am trying to explore the lower limits of the router flattening jig technique because of limited resources. As far as I can tell, no one else has done boards this small. Is that because it's unsafe?

Thank you, 
Paul


----------



## epicfail48 (Mar 27, 2014)

How flat are the sides when you start? That really determines what holding methods you can safely use

If the sides are already pretty flat, workholding is easy, you can either use just double-sided tape, or use the painters tape + super glue trick, either option will hold your pieces plenty securely, so long as you arent trying to hog off 1/2" depths. Taking off a 1/16" wont be a problem

If the sides arent flat enough to get good contact from the board to the tape to the sled bottom, youll need to think outside of the box a bit. What ive done in situations like that is to lay down a lot of hot glue and press the piece firmly into it. The hot glue fills the gaps and keeps everything secure. Do that to flatten one side, flip, and use double-sided tape on the now flat side


----------



## DrRobert (Apr 27, 2015)

What are you trying to build? Thin boards like that are very hard to 1) get flat ans 2) keep flat. Depending on project, they can be flexed into position.

The problem with router planing 1/2” thick boards is flexing, seems to me you would almost have to use some type of bedding compound to fully support it.

I don’t know where you are planning to go in ww’ing, but like anything else, you need the right tools to do a good job. If you can’t afford a planer, my suggestion is buy a cheap No. 5 1/2 Stanley or similar hand plane (no, NOT Harbor Freight OR Buck Bros please, and no modern Stanleys please). Ones that needs refurbishing or ”rustoration” can be gotten pretty cheap. Take a look at some videos on flattening with a hand plane (Wood by Wright, Renaissance Woodworker).

Yes, going this route means 1) you need to learn to use a plane, 2) sharpen a plane iron, 3) use a marking gauge, 4) make some winding sticks, 5) a work bench that can hold a board face down ………but the payoff is worth it.

All that said, you’re not going to flatten a 1/2” thick board very easily no matter how you do it.


----------



## Tool Agnostic (Aug 13, 2017)

Nobody has mentioned sanding yet. Sometimes re-sawing to make a thin board doesn't yield a perfectly flat board, and I have used hand sanding to get them flat.

I have hand-sanded thin boards to make them flat. Sometimes the boards are made of very hard wood, but starting with low grits (rough sandpaper) makes it go faster. Then you have to work through the finer grits. 

I have a good friend who is very skilled with a handheld belt sander. I have seen him flatten boards with it. It takes practice, skill, and physical strength to control the belt sander. Myself - I leave gouge marks with a belt sander, so I take my time with hand sanding.


----------



## Plane (Sep 19, 2021)

This is all great feedback. 

For more background, the project I am working on is taking reclaimed 1/2inch thick boards of various lengths and width (see range above) and making a desk top. 

Planned method:

flattening each side
rip them to 1 to 1 1/2 inches wide
glue faces together to make desk
Use table/circular saw for final dimensions
Flatten/finish pass desk top with router/slab jig
The Smaller width boards are essentially flat, with a rough/non-smooth surface. Maybe some slight cuping. The glob of hot glue technique would seem to improve the hold down and make "slabbing" these 1/2 inch boards safer. 

The wider boards should be able to be ripped down the decrease the cupping seen on the wider boards.

I enjoyed watching the hand plane restoration videos, so thank you for that tip. This is a viable option, however with the number of boards I have this may end up taking a while. I will have to consider this option some more. Plus restoration time.

I have an orbital sander which may do the job for the best of the smaller boards to clean them up. However if it's between buying a router and buying a hand held belt sander, I would consider the router more versatile.

To be clear, I intend to attempt to "slab" with a router and slab jig, to flatten/plane one of the 3inch wide, 1/2 inch thick boards as a test. Using Clamping option 1, with hot glue to conform and support the piece. I will stick to 1/16inch passes. 

Please let me know If this might be completely unsafe for some reason I am glossing over? Primary safety concern is due to the small width and thickness, as the technique is popular.


----------



## firehawkmph (Apr 26, 2008)

Might want to look at a used table top jointer for boards that size. 
Mike Hawkins


----------



## woodnthings (Jan 24, 2009)

Make some "L" shaped clamping jigs like this:








You can make them using two 3/4" thick boards and glue them together.
Put sandpaper on the inside edge to grip your smaller boards better.
The vertical edges should be long or tall enough to become the rails for your router sled.
Check the depth of your best 1/2" diameter or 3/4" router bit to make certain the bit will reach your work pieces.
You can insert small wedges under the board for more support if you want to. I never needed them.
Now you have an adjustable clamp for various width and length boards.








These clamps can really grip with great strength. The redi-bolts I used are 1/2", but you could probably use 3/8".

Here's how I used them in my thickness planer as an experiment to flatten a wide board as you would use a jointer:








Planer sled on "rails"


Planer sled My version came from my "gluing frames" and thinking about a 2 rail system which simply screwed into the edges of the board to be planed. Heck, I already had a gluing frame, why not try it? The following photos are...




www.woodworkingtalk.com


----------

