Re: [Harp-L] Flat sanding problems



By hand-sanding away .5 mm of thickness, you will inevitably spoil the flatness. 

I suggest the following:

Method 1.  Routing
Chuck a 1/4" or larger, new, sharp router bit or end mill in your drill press.  
Use maximum rpm.
Clamp the comb level in the drill press vise.
Set the bit height to remove .5 mm.
Slowly and gently push the vise around to remove the unwanted comb thickness.
Push the vise so that the blade tips of the bit move tangent to each partition and toward the thick back of the comb. 
Keep your hands away from that router bit!

"But I don't have a drill press!" you say....

...If the combs have any value, then the ones that you avoid ruining should quickly pay for a small drill press that you can also use for other purposes.  The satisfaction of doing it right has value.


Method 2. Guided Sanding
Attach the comb to the flat surface with double-sticky carpet tape.  Then glue coarse sandpaper to an "upside-down" sanding block that is both 6 inches longer and wider than the comb.  Put four (brass to avoid scratching the reference flat) screws near the corners of the block to act as legs. Adjust them to protrude downward by the desired 5.5 mm comb thickness.  A 12" x 12" granite floor tile makes a good, easily-obtained and inexpensive reference flat.  

Then have at it.  Any part of the comb that is thicker than the leg-length gets sanded away and any part thinner than the leg-length does not. Use wet sandpaper for plastic combs.

If you find a better method, I'd like to know about it. 

Vern
 
On Dec 27, 2012, at 1:24 PM, Boris Plotnikov wrote:

> Thanks guys for responce. Just for experiment I just tried to flat sand
> wood 1847 comb. The same crap, borders is thinner than center. I'll buy
> coarser sandpaper tomorrow and will try again.




This archive was generated by a fusion of Pipermail 0.09 (Mailman edition) and MHonArc 2.6.8.