5/16 or 19/64 ?

[Groves]

I see that Grainger has a stunning assortment of parabolic bits in both 19/64 and 5/16 diameters. They range from $2.76 on up to $16+

I'm ready to join the fast chip-clearing world.

Any difference worth noting between the performance of these different sizes?

[maple flats]

I have used both conventional wood bets and those designed for tapping maple. I'll never use another std bit. Maple tapping bits are far superior.

[Grade "A"]

I once tried first tapping with 19/64 bit then later in the season I would re-drill with a 5/16 bit. The re-drilling didn't help me much but I saw that the spouts would seat better with the 5/16 hole. Now I only use a 5/16 bit.

[user587]

Maple Flats (and anyone else for that matter),

What style maple-bit do you find works well? (see attachment below)

Thanks,
Scott

[Groves]

I have used both conventional wood bets and those designed for tapping maple. I'll never use another std bit. Maple tapping bits are far superior.

I believe the main difference in the special "maple" bits is the rapid flute which helps clear chips, and there's less contact with the wall of the tap hole which reduces burnishing and damage to the fibers resulting in better sap flow. They're sharp, too.

These differences are all present in the "parabolic" bits at grainger. All of the grainger bits are 135deg grind, and maybe the maple ones are 90deg.

The grainger bits are definitely maple worthy, I was just wondering whether to get the 19/64 or the 5/16.

[bigtreemaple]

My old tapping bit has the initials PTD on it. I have often wondered what that means, could the P stand for parabollic, and what exactly is a parabolllic bit? Just curious.

[lpakiz]

I use drill bits alot in my shop. I noticed that my tapping bit (parabolic style) has VERY sharp sides to the flutes. Just lightly push the leading edge of a flute (an inch or so down from the tip) across your thumbnail, then try a new regular bit. You should note a difference.

[lmathews]

The size of the bit depends on the tap you are using.If you are using the 5/16 check valve or weather you are using the ipl 19/64 tap.

[moeh1]

Probably stands for parabolic tap deep. They are designed for deep hole drilling, thus the rapid chip removal. The flute design also gives a bigger central core, so they are supposed to be more resistant to snapping off. You can get them with all the cobalt/nitrited coatings, Fastenal carries them too.

[markct]

yea i have many different drill bits around from when i was a machinist, now i just have my machine shop at home, but of the many different styles, for plastics, alum, fiber stuff all sortsa different things, none have as sharp of flute edges as my canadian bits from bascoms! they are amazing how sharp the flutes are, and they work so well that they are well worth the money!

[SeanD]

I agree. After I pushed a stopper onto the one I got last year, I started noticing red marks everywhere in the kitchen. Turns out the edges sliced up my hand pretty good and I didn't even realize it. I was used to dealing with typical bits. Big difference. These are very sharp.

Sean

[farmall h]

The tapping bits are made to bore hardwood at a slow speed and have a clear hole when your done. A sharp bit on a Tanaka tapper only requires one plunge with the drill. It's as simple as in-n-out! Also, you will notice that you have a very clean, sharp edge on the entrance of the tap hole...no fuzz or sappy mush from a highspeed portable drill. Your normal wood bit tends to bind in wet wood as well. That's what I have noticed anyway.

[SeanD]

I actually use a high speed portable drill. I would have thought fast and quick would be best (I'm still talking trees, here). Should I dial it down?

Sean