What not to do - chipout example

[hfmann]

Well on the last slot of the riser top, the router bit must have been touching the acrylic. When I turned on the router it caught and broke out a piece of acylic and chipped out the edge. Here's a closeup on the bottom.

Fortunately, i've got some extra 3/8" black cast I can cut down and machine. Next time, I'm going to drill the starter holes a little larger.

Question is: Is this piece destroyed? Since it is the bottom of the piece and doesn't show, will it work anyway, or is it stressed too much.

If not usable for our calc reactor, brian can I use it for my upcoming KW reactor project....or is this just good fodder for the scrap recycling bin?

Hope this helps someone else avoid the mistake.
Hal

 

[Casie]

Yikes! Thanks for sharing your pic, Hal.

I'll be cutting my reactor peices tomorrow morning. I will definitely be wearing my lucky socks.

 

[hfmann]

Your welcome Casie, but this sure was frustrating for a while.

It happened 6 more times, fortunately on scrap that I decided to "learn" on and gain confidence. The self confidence took a long time to get with each failure. I'm offering several possible causes for this happening to me, not really knowing if any one of them was "the big one".

1) I used a drill press with a backing board for drilling the holes. I found the backing board was slightly cupped which may have caused the holes to not be perpendicular. If this happened it would have presented a much smaller opening for router bit not leaving enough clearance.

2) On the drill press, I set a stop depth and may not have been drilling enough of the way into the support board to get the full diameter of the drill bit clearing through the acrylic. Again this would have caused a smaller hole with possibly not enough clearance for the router bit.

3) I may have had the router bit set too high, offering too much of a cutting edge on the bit exposed to "catch on".

4) In trying to hold the acrylic piece firm when starting the router, I could have been applying more sideways pressure than verticle. in an effort to keep my fingers away from the router bit. When the router started, maybe I was "jerking" a little causing the acrylic to slide sideways.

I changed all three of the above setups and focused on pressing the acrylic piece down. I didn't have a single problem after that.

Boy was I getting paranoid! The chipped out bottom surfaces are rather sharp. If I "smear" some Weldon 16 on this to smooth the rough edges and fill some of the chipped out areas, would the piece beausable, albeit unsightly?

Can't wait for the class to see if anyone else had similar problems.

 

[fergy]

It will be hidden entirely on the finished product...only you will know it's there.

Looking at it, it looks like the bit is set too high, because I can see where the bit cut into the template when it bounced like this.

A future option would be a larger drill bit. But, for this project, you needed the smaller bit as well, so I didn't think everyone wanted to buy a second. If you're going to do this again, you might invest in the next size up.

Might want to have someone else turn on the router table for the first few, until you get the feel.

BRIAN
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