Dog paw bowls, many mistakes, or how I made a new friend
I was trying to come up with a project to play with the wood table tops I recently acquired. I had purchased a plan for dog paw shaped bowls last year, but didn't have any stock on hand that thick. It was designed for 1.5 inch stock, mine was just shy of 1.75 inch. I scaled the file to fit on the piece of counter I had planed, and rotated and flipped patterns to get 4 on one blank.
I tried to figure out the best way to hold the blank down, and decided to hot glue it to the sacrificial table. This held surprisingly well. I used 1 stick of glue, and when I removed the blank it just tore the tiniest bit of paper off of the MDF.
The rough pocketing tool path was run, and it was exciting to see the paws to appear from the board. I was also excited that so far, no errors!
The project called for a 1 inch bowl and tray bit, which I was sure I had. Nope. I have a 1.25 inch bowl and tray bit. The bit geometry wasn't going to work with the size of the pockets being cut, so a trip to the store was in order. Nothing local, so drive north an hour to Woodcraft. They don't have a 1 inch either, but they had a 3/4 which I could make work.
(In the 5 minutes I was in the store, a nice young lady backed up within a whisker of my tailgate, I guess those sensors on the back of her car don't see above the bumper. Fortunately she didn't hit me! That would have made for one very expensive router bit.)
I chuck the bit up in the router, recalculate the tool path for the smaller diameter and ran the program. The first pass went fine, but on the second pass the router was screaming. I manually dropped the feed rate of the router until it sounded happier, and waited forever for it to finish. During that time I realized that I had left too big of an allowance on the roughing tool path, because I was expecting to use a larger bit. That poor bowl and tray bit was trying to hog out almost 1/2 of it's diameter. Fortunately, I didn't break the bit, or burn the wood.
The finish pocket tool path flew by, and I was beginning to feel really good about the project. I chucked the end mill in to cut the parts out, fired up the tool and watched the first few passes of the cut out and it looked great. That is when the universe conspired against me! I step inside for a quick trip to the head, and heard the next pass start, a funny rattle, then it got a lot quieter. I ran back out to the garage and found the end mill had come out of the router. It looks like it had tried to burrow into the wood, as it had drilled a hole in the bottom of the blank. I hit the emergency stop and assessed the damage. The machine, router, and bit were all in good shape.
Fortunately it only destroyed one of the parts, but now I had a bigger problem. By hitting the emergency stop I now had lost registration with the original x,y zero. I stepped through the program until I could line up the router with the blank and re-zero everything. I was able to get very close, and ran the program to see if it would follow the original groove, which it did pretty perfectly.
This is when I decided that if I was going to leave the machine even for a second, I was going to have to hire somebody to watch it for me. Fortunately I found a little fellow at WalMart who agreed to do that for only $30 on clearance. Stuart stands on the computer cabinet and keeps an eye on everything for me. I can watch him either on the phone or on my PC.
I cleaned the bit and collet, clamped it back into the router and ran the remaining cut. I knew my bit wasn't long enough to cut the piece all the way out, so I took it to the bandsaw and cut them free. I used the ruined piece to practice my roundover setup, and when I was happy with the result I was able to clean up the other 3.
The piece still needs sanding and finish, but my bride has already posted it on Instagram, and someone already has expressed interest in one of them. If I am going to make more of these, I will definitely have to work on optimizing the work so it doesn't take so long to mill.
Lot of work, a lot of challenges, but learned a lot. And I have a new, little yellow buddy in the shop with me. I haven't decided how I am going to mount Stuart just yet, wheter he stays on the computer cabinet, if he gets mounted to the gantry, or if I mount him up high to get a full view of the table. He takes an HD image, and you can zoom in and see quite a bit of detail. When I use the phone there is a 1 second delay, when I use the browser window it is 2 seconds. Still enough time to prevent a mistake from turning into a disaster.