I'm working on a hardwood box and cribbage board combo, so I knew I wanted very precise peg holes. The internets is full of suggestions for jigs to allow you to do precise drilling on a drill press. The idea is to brace the work piece against a backstop and use stop blocks to gradually move the piece horizontally for drilling each hole. American Woodworker had a photo of a jig using flip blocks that looked cool, but no Instructions on how to make one. Sounds like a project! Read on to learn how to make your own cribbage board drill press jig.
I made this jig in the woodshop at Tech Shop in San Jose. If you live in the Bay Area or one of Tech Shop's other locations, it's a cool place to check out - lots of tools and interesting classes. And, if you write an Instructable based on your work there, you win a free class. Check out their website: http://www.techshop.ws - maybe I should take the CNC class so I don't have to build a jig next time I need a zillion holes drilled :)
Step 1: Materials and Tools
-2 two-foot pieces of poplar stock (or another wood - someone recommended poplar to me, but it was a little too soft. I had some splitting when it came to drilling holes)
-2 four-foot pieces of 1/4" thick poplar hobby board, 1 inch wide
-1 long wooden dowel (needs to be the same length or longer as your wood stock)
-A few screws
-Your cribbage board wood and some test scraps
-Drill press and bits
-Hand drill and screwdriver
-Table saw with cross-cut sled
-Clamps and stop blocks
Step 2: Jig Design!
-Your jig should be square
-You'll need a jig approximately 2X as long as the cribbage boards you hope to make - two feet is a good length
-Make sure that your drill press can clear the various parts of the jig in order to allow you to drill your holes
As I built this jig, I continually dry fit pieces on the drill press itself to make sure that I had the necessary clearance for the both the cribbage board and the drill.
Step 3: Build the Jig Body
Notes for the backstop:
-Make sure your back stop is square! Use a jointer and planer if it isn't.
-Make sure your back stop isn't too high - it may stop the drill from being able to fully lower. Mine was originally an inch or so too tall, so I ripped it on the table saw to cut it down to a better size.
Notes for the arms:
-I used a piece of scrap to test out several drill bits until I found one that made holes that fit my dowel snugly. Then I drilled two holes in each arm (this will allow for raising the dowel to a higher height to accommodate odd shaped cribbage boards.
-I attached the arms to the backstop with wood screws, pre-drilling the holes on the drill press to prevent splitting.
-Make sure they're square!
Notes on the runners:
-Two runners attached to the jig to fit in the grooves on the drill press will allow you to slide the jig back and forth. This is one area where I sort of free-styled it, and maybe could have found a better technique. I cut the runners to size and screwed them in one at a time (again, pre-drilling holes to prevent splitting) but had trouble getting the second one in the right place. I got frustrated trying to get the second runner in the exact right position and eventually just sanded off a few millimeters with a belt sander until it fit in the groove. The jig isn't a perfect fit in the base, but it's pretty good.
Step 4: Build the Flip Stops
Cut the stops
These stops were made from the two four-foot lengths of 1/4" poplar hobby board. I wanted enough to be able to cover the length of a 12" cribbage board, which means roughly 48 stops (four stops per inch X twelve inches). To cut them to size I set up a table saw with a cross-cut sled. I clamped a stop block to the sled so each cut of the hobby board would be two inches long (and thus, with my two 48" hobby boards I should get close to the 48 stops I wanted). See photo for the stop block set-up.
Drill holes in each
I then took the stops to the drill press to drill holes for the dowel to pass through. I used a drill bit that I had tested on scrap wood to fit the dowel with a little wiggle room so the stops could swing freely (not the same bit as used for the arms of the jig in the previous step - this was a size bigger). I clamped a piece of scrap to the press and penciled in the shape of a flip stop to get the hole in the position I wanted, identical for each stop. In a classic example of a novice wood worker not letting the tool do the work, I split the first three stops by drilling too fast. Once I slowed down my drilling and lowered the bit with steady, even pressure, I had no more splits and soon had a stack of flip stops with holes for my dowel.
Step 5: Assembling the Jig and Taking It for a Spin
Definitely do a test run with a piece of scrap. Watch out for the following:
-Is your jig square? As you run the work piece along it, do your holes end up in a neat row?
-Is your work piece square? If it isn't, you'll have a tough time getting the holes lined up in a perfect row.
-Are there any problems with the jig itself and getting the actual drill past your jig so it can do some drilling?
-Do you like the spacing of the holes?
-Does your work piece slide nicely along the back stop? Mine got snagged on the tops of the runners, so I sanded them down a hair.