BTS-002 - CMT Bowl and Tray Kit
Owner’s Manual
Thank you for purchasing the CMT Bowl and Tray Kit. With this kit you can make platters and bowls up to 70mm deep. Bowls and platters
make great gifts, and they’re a great way to use up scrap wood. There’s no end to the different combinations of wood and shapes you can
create with this kit. Please read all the instructions thoroughly before using the BTS-002 kit.
Tool Requirements
- 1300 watt or larger plunge router with variable speed
- Forstner bit, 35mm or larger
- 12,7mm radius roundover bit (CMT #938.880.11 w/ 12mm shank, or,
#938.380.11, w/8mm shank)
- Drill Press (Note: The bowl can be excavated with a router only.
It just takes longer and puts more wear and tear on your router and bit.)
- Soft disc sanding pads designed for bowl turning for sanding bowl interior.
(Available where turning supplies are sold.)
- Compass
Get Started
Unpack the CMT Bowl and Tray Kit,
which includes a Bowl and Tray
bit, collet extension and two bowl
templates.
Glue up a bowl blank. Make an 460x460mm blank to use with the round bowl template
and a 380x590mm blank for the oval template. Thick stock works best, but you can stack-
laminate thinner boards to build the blank to the desired depth.
Note:
A 70mm deep bowl is about the max for most routers.
You can mix woods in your bowl blank. A layer of contrasting wood at the top is a nice
touch. Like bowl turners, you can have a lot of fun experimenting with different woods and
different glue-up patterns to achieve stunning results. It’s important to align your boards
perfectly flush in the clamps to avoid unnecessary sanding to flatten out the blank. This is
especially true if you are going to stack-laminate or add an accent layer as shown here.
Lay out the bowl using the template. Center the template on the blank and mark the
first partition. Remove the template and make marks exactly 12,7mm from the edge of
the first partition. This defines the wall thickness for each partition. It’s important to be
exact in order to achieve a uniform wall thickness for all the partitions. Use these marks
to align the template for the two adjoining partitions. Make additional marks to position
the template for the last partition.
Use a Forstner bit in a drill press to remove most of the wood. Forstner bits do the best
job because they can make overlapping cuts and leave a flat bottom.
Drill the holes to within 3,2mm of your layout lines. Set the depth of cut to stop short of
the finished bottom so the router bit can clean up the dimples left by the center point in
the Forstner bit.
Note:
It’s best to use a bit whose diameter is larger than the 31,75mm diameter Bowl
and Tray Bit. If you must use a Forstner bit less than 31,75mm, don’t cut too close into
the corners or the router bit won’t be able to clean it up.
Once the partitions have been excavated on the drill press, it’s time to move on to the
router. First, make an extension router base plate that’s large enough to safely bridge the
opening in the template. The base plate can be made of 12,7mm sheet stock or 9,5mm
thick acrylic or polycarbonate plastic. Drill a 50,8mm hole in the middle of the plate.
Mount the extension base to your router.
Next, assemble the collet extension using a 14mm and an 18mm wrench. Insert the
bowl-cutting bit into the collet and tighten using a 27mm wrench and the 18mm wrench.
Warning: You must have at least 2/3 of the bit’s shaft length inside the collet. Do not
try and extend the depth of cut by overextending the bit from the collet.
Insert the collet extension into the router and tighten.
Note:
Be certain to unplug the router whenever changing bits or making adjustments to
the router.
Mount the template on the blank so it lines up exactly with the previously drawn lines.
Drill and countersink at least two holes in the template. Be sure to locate the holes over
the waste portions of the bowl where they will be removed later. Fasten the template onto
the blank with flat head screws. Make sure the screw heads are set just below the surface
of the template so they don’t interfere with the router.
Set the plunge router’s turret stop for a cut deep enough to finish the bottom of the
bowl.To do this, set the router on top of the template on the bowl blank and plunge the
unplugged router down until the bit bottoms out. Set the stop so the bit will plunge ano-
ther 3,2mm - 4,7mm beyond the drilled out bottom and remove the dimples left by the
Forstner bit’s center point.
Finally, be certain that at the top of the router’s travel the bearing on the router bit is riding
on the template. This sets the router for the first pass. If your router has a chip collection
attachment, be sure to use it.
Secure the blank to your bench. With the plunge mechanism set at the top of its travel,
place the router over an open area on the template. Make sure the cutter is not contac-
ting the wood and turn on the router. Gently slide the router to the template edge and
begin your cut. Continue the cut around the opening.
Then, lower the bit 9,5mm and make another pass. Eventually the bearing on the bit will
drop below the template and begin to register on the wall of the bowl itself. Keep making
