Had an issue with tapping

[ebliese]

I put a 5/16" section of tubing on my 5/16" tapping bit to limit taphole depth. I set it up so I would have a taphole depth of 1 3/4" (includes bark). Unfortunately, upon finishing tapping over two days, I noticed the tubing section had slid down and made the taphole depth 2 3/4". I think this happened gradually so it's not like half my tapholes are at 2 3/4" depth but I wasn't paying attention. I did notice the tapping was getting harder but I thought maybe it was the bit getting dull which seemed strange because we had only used it for 200 taps over a few years. I probably should have stopped and examined the situation but I had never had anything happen like it before. Looking at the tapping bit, it seems like they designed the bit to be harder to drill past about 2 1/2".

I double checked in the 3rd ed. of the North American Maple Syrup Producers Manual. Tapholes on for buckets are drilled 2-2 1/2" into the trees. The reason to limit taphole depth is to prevent from encountering a previously tapped area or heartwood. All the shavings I saw were good wood and I stayed true to my tapping pattern. So being an extra 1/4" deep, while not ideal, should be ok?

Just hadn't had this happen before so I wanted some advice. Thanks!

[Sugarmaker]

Dan,
Should not be a big issue. They do make a collar to set screw on to the bit. We just drill by feel. Our old maples have a inch of thick bark on them. Your doing good!
Keep boiling!
Regards,
Chris

[Pdiamond]

Wondering how you were doing Chris?

[ebliese]

Pdiamond, I had thought of your method...only after I was done tapping and realized my mistake. But I'll plan on using it next year!

[Pdiamond]

Daniel, what I have found that works for me is to use a piece of 5/16's tubing, as you did. What I do is place the bit into the drill motor then the tubing goes all the way to the bottom against the drill motor. You should then only have 2'' protruding and the rest covered by the tubing.

[OnePot]

I mark the bit with both a black and silver sharpie so I can see it. But it probably isn't as good as tubing if you are going fast.