Tuesday, May 25, 2010

Simple Ways to Reduce Snipe with Lunchbox Planers

I wrote this a long time ago and, as the article states, my lunchbox planer was installed in a machine stand at the time (the trick relies on the planer being portable).  Although I describe everything here, photos are lacking.  I've since rolled a video explaining it all here: How to Eliminate Snipe on Lunchbox Planers.

Snipe sucks.  Even starts with an "S", too.

A lot of people have tips to gently lift the piece as it enters the planer and press down as it exits or the usual "you just need to make sure the tables are coplanar" (duh).  Thing is, the lift can introduce a hump in place of the snipe and even if the tables are coplanar, most are rather flimsy and flex under the variable load of the board (variable due to the change in loading as it enters the lunchbox).

Before getting a battleship (er, sorry, PM20 planer), I had a Ridgid 12" lunchbox and honestly I highly recommend it.  To avoid the problem with snipe, I wanted more stable tables on both sides especially for the long boards I was running through (my first projects had dimensions from 4'-8' routinely... don't ask).

My solution was to build two torsion boxes and top them with strips of melamine-coated particle (MCP) board.

I made them as torsion boxes on an assembly table to ensure they were flat.  Using strips of MCP allows the stock to move smoothly (with half the friction since half the box isn't covered) and allows a place for ejected chips to go rather than lodge under the stock.

Now, I have since put my planer inside a stand so removing it for a picture is an hour affair, but the way I used these tables was to put the planer on the assembly table shown with a table on the infeed side and the other on the outfeed side.  The stack of grey wood are shims to get the tables to the correct height.  Since the assembly table is built to be flat, I can place the planer anywhere on it with the in/out-feed tables and have everything work well.  This was extraordinarily useful with longer stock.

Today, I use this planer for drawer stock or small box stock (think small thin stuff).  Since I cannot put the planer on the assembly table, I put one of the auxiliary tables inside the planer.  Written on the side is 82mm, the thickness of these tables.  I always plane in metric since fractional millimeters are easier to deal with than imperial measures.

In my case, I'm reusing the tables I already made that were about 4' long, sized conveniently to fit on my assembly table in the original orientation.  If you like this idea and want to use it, I'd suggest making a 5' box so you have at least 2' on each side (maybe even longer).  Other than applying the offset, everything is the same as before, except no lifting or feeling shame that apparently your tables aren't as coplanar as the other guy (-psst!- he likely read it on a forum :)


  • Vision Celest said...

    I laid a 1/2" slab of MIC6 aluminum jig plate, about 12.75 by 30 inches, on top of the table, using maching screws to hold it down.

    Lost 1/2" of capacity and drilling and tapping the table was a pain, but it works great.

  • HalfInchShy said...

    Love the solution! Same basic concept: eliminate the flex in the tables! I could see someone benefiting from that for a more permanent setup where you don't need to flip up the tables. You lost 1/2" of capacity whereas the boxes I was using took out 4" :)


  • Anonymous said...