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Foam Rubber Drill Bits

More info about Foam Rubber Drill Bits


Drill Bits for Foam Rubber:  The bit that I used for the Ski-doo seat is 24 inches long and 1 inch in diameter with a 0.47-inch shank so it will fit into a -inch drill.  I can sell you this bit, or a similar bit that is 0.75-inch in diameter (with a shank just under -inch) for $100 + shipping.  A bit that bores a -inch hole (also with a -inch shank) is $50.

Drill Bits for Foam Rubber
Approximate Hole Diameter 1 inch (~ 25.4 mm) 0.75 inch (~ 19.05 mm) 0.5 inch (~ 12.7 mm)
Approximate Shank Diameter ~ 0.47 inch (~ 11.9 mm) ~ 0.47 inch (~ 11.9 mm) 0.5 inch (~ 12.7 mm)
Approximate Bit Length 24 inches (60.96 cm) 24 inches (60.96 cm) 24 inches (60.96 cm)
Price (US dollars) $100 + shipping $100 + shipping $50 + shipping
Also available:  a complete set of bits (one each of the 1", 0.75, and 0.5 inch bits) for $200 + shipping.

I can produce a 3/8" (~ 9.5 mm) or 1/4" (~ 6.35 mm) shank on request to permit use in smaller drills.

I can also make bits of other diameters and lengths to suit specific applications.

Payment:  Check or money order.

My address is:

Kevin Pezzi
6680 Traverse Road
Thompsonville MI 49683

I also sell a jig to align the bit to ensure that the holes are perfectly horizontal and perpendicular to the axis of the seat.  This jig isn't absolutely necessary (I drilled the Ski-doo seat freehand), but I recommend it for optimal results, especially if your holes are closely spaced.  Generally, with smaller hole diameters, you will drill more holes, so they will be spaced tighter together.


  • Save the cores produced by drilling.  If you drill too many holes and the seat is too soft, you can re-insert some of the cores to increase the seat firmness.  The foam rubber drill bit makes an ideal insertion tool for these cores.  Here is the process:  1) insert the core in the bit, 2) push the bit through the hole, 3) grab the end of the core (at the tip of the bit) when it is flush with the far edge of the seat, and 4) withdraw the drill bit while still holding the end of the core.  If necessary, gently tug either side of the core to make it flush with the side of the seat.  If you wish, you can apply a small amount of glue on each side to tack it in place.  Special foam rubber adhesives are available, but not required since you can bond it with silicone adhesive or caulk.
  • You can insert cores of lower density (softer) foam rubber into the holes to modify the seat characteristics.  Blocks of foam rubber of various densities are available from upholstery shops, but these are usually open-cell foam that can absorb moisture.  Most snowmobile seats are closed-cell foam that resists water absorption.  If you use open-cell foam, I recommend that you tack the core in place with silicone adhesive as described above, then smear a thin coat of the adhesive over the ends of the core to seal it.
  • You can bore different size holes in each seat.  For example, you can bore -inch holes near the top of the seat, 3/4-inch holes in the middle, and 1-inch holes toward the bottom.
  • After you remove the seat cover, sit on the seat.  It will seem softer since the seat cover is fairly occlusive and traps air.  The seal isn't perfect since air leaks out around the stitching and at the seat bottom around the staples.  In use, your seat will be stiffer than what it seems to be at rest because it takes time for air to be pushed out (during seat compression) or sucked back in (during seat expansion).  Thus, the dynamic seat stiffness is greater than the static seat stiffness.  Whomever engineers snowmobile seats evidently gives no thought to this matter, and they don't bother to tailor the seat dynamic compression and expansion (rebound) pneumatic characteristics.
  • Seat core modification can be carried out on other vehicles, such as personal watercraft.
  • Lubricate all surfaces (inside and out) of the drill bit before use, and periodically during use whenever it begins to drag more.  Properly used, it will produce beautifully round, straight holes.  Use spray silicone lubricant, and distribute it with a rag before wiping it dry.
  • For maximum safety, use a drill with an adjustable torque clutch (and set the clutch just high enough to permit drilling), or simply use a wimpy drill that doesn't put out much torque.  If you use a powerful drill without a clutch and the drill bits grabs (most likely because it is dull or had insufficient lubrication, or you're trying to drill too fast), the drill might whip out of your hands and injure your wrist or other body part.
  • The tip of the bit is very sharp, so keep it out of the reach of children, and place it in a secure location where no inadvertent contact will occur.  Depending on the number of holes you drill, the bit may need to be re-sharpened, which can be done with a file or stationary disc sander.

Organize your garage beautifully.

If you want a beautiful garage that is easy to keep organized, see the GarageScapes web site: www.GarageScapes.com.



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