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View Full Version : Carbide Forstner bits?



Kelvin Burton
12-24-2013, 10:15 PM
When making my Travel mugs (http://www.sawmillcreek.org/showthread.php?211716-4-more-out-the-door!) I had to sharpen my 2 1/4" forstner bit multiple times per hole. Boring 2 1/4" 5 1/2" deep into end grain Mesquite was quite a chore and I did it 6 times! I also noticed that the bit was only cutting on one side.

Another club member has been extolling the virtues of carbide tipped forstner bits but there's a huge range of prices out there for any given size. He recommended the products on Woodline.com. I see Grizzly are selling sets of 16 bits for $119 - has anyone out there used these and can tell me whether they are any good?

Amazon sells Freud but they are more than double the cost of any others I've seen.

Opinions please!

Phil Thien
12-24-2013, 10:25 PM
I have the Grizzly, both sets. I'm happy with them. One thing to keep in mind is that the sharpest carbide isn't as sharp as the sharpest HSS. But the carbide keeps what edge it DOES have much longer.

So they require a bit more force to cut, but they stay sharp a long time.

Now, I've never bored 5" long holes in end-grain, I don't think the Grizzly bits are even long enough to go that deep w/o adding some sort of extension.

Doug Herzberg
12-24-2013, 11:23 PM
I have a set of Woodlines, but the largest is 35mm for cabinet work. All the other sizes are in inches. Haven't used them much, but I did some 3/4" bench dog holes in sidegrain Ambrosia Maple. Like Phil said, not as sharp as steel, but they don't get worse. Pretty clean cut. My set of 5 or 6 was $39 at the woodworking show. I also tried a really cheap Chinese 100mm I found on Amazon into endgrain on the lathe. The bit was not intended for that and it didn't do well. If you're always doing the same size, maybe one Freud would be better than a set of cheapies. Good luck!

Ricc Havens
12-25-2013, 9:06 AM
Kevin. This may be a dumb question - but Are you drilling the 2-14" straight into the end grain? Or are you using smaller forester bits to start and increase the hole with each size forester bit? I have a good luck with the Porter Cable $50 set at Lowes http://www.lowes.com/pd_306070-70-PC1014_0__?productId=3032014&Ntt=forsnter&pl=1&currentURL=%3FNtt%3Dforsnter&facetInfo=

But I start with 7/8" and the step up to 1-1/8", 1-1/2", 1-3/4" (bought separately since not in box set), then the 2-18". I then use a homemade hollowing tool with a square carbide bit (similar to a Easy Wood tools "easy rougher") to hollow the interior to the final tapered hole to fit the stainless mug insert. I have done a couple dozen mugs this way without having to sharpen the forester bits. Most of the mugs have been in woods like cherry. BUt I have done a couple out of really hard and dry osage orange. Since the osage was harder I started with a smaller forester from the set and used a few more between so the bits wouldn't overheat.

I also assume that you use a slow speed and blow out the debris a lot. but if you don't do that it will help if you do.

Also, if you search youtube for Capt'n Eddie videos (he has over 200) one of them shows how he sharpens his regular forstner bits and makes his carbide tools. I have no connection financial or otherwise with him but he sells the square carbide cutters at a great price and is where I got the idea and supplies to make the one I use.

Good Luck with whatever you do!
Ricc Havens

Greg Just
12-25-2013, 9:44 AM
I make a lot of travel mugs too and I got tired of buying forstner bits. I use the Termite hollowing tool now. This works well for me.

Dennis Ford
12-25-2013, 9:48 AM
I have a couple of Freud carbide drills and they are very expensive and very good. For pepper mills I bought a "Colt 5 Star" drill bit and it is also very good. I have not tried the less expensive carbide drills but will be watching this thread for reports.

RL Johnson
12-25-2013, 12:34 PM
Rockler has some long shank bits but they only go up to 2 1/8" in carbide and are 4 1/2" overall in length. I have used them and like them real well but the big diameter bit is $55, at bit steep for a single bit.

Kelvin Burton
12-25-2013, 2:38 PM
Ricc, I was under the impression that with forstner bits you needed to drill with the final size all in one go so that the center point had something to "center" on. Hence I have not been stepping up through the sizes. The directions for the Travel Mug suggest drilling a 2 1/8" hole but as I already had a 2 1/4" bit I figured the extra 1/8" wouldn't matter. I drill slow and clear the shavings frequently and found I could drill 4 cm before having to completely draw out the bit.

I do have the EWT easy rougher and that worked great for turning out the tapered inside. I use a can of air to blow out the shavings as I go.

I'm familiar with Capt'n Eddie - just watched "#148 Forstner Bit Touch-up", he's a character isn't he? :o

Duane Meadows
12-25-2013, 4:47 PM
NO, that's actually one of the advantages of a forstner bit. You don't need the center point as long as the work piece is held securely. You can drill a partial hole on the edge of a board, or drill a hole at an angle, if you want to. The key is having the workpiece held securely. Assuming of course you are not using a hand held drill!

Jamie Buxton
12-25-2013, 6:43 PM
NO, that's actually one of the advantages of a forstner bit. You don't need the center point as long as the work piece is held securely. You can drill a partial hole on the edge of a board, or drill a hole at an angle, if you want to. The key is having the workpiece held securely. Assuming of course you are not using a hand held drill!

Well, it is true that after it gets started the Forstner guides from the walls of the hole, so the center point isn't needed. However, the problem for me is to get the bit started. If the center point doesn't grab, the first part of the bit to touch wood is one of the spurs. When that happens, everything tries to rotate around that spur. Either the bit or the workpiece usually goes sideways with great force.:(

Barry Richardson
12-26-2013, 3:58 AM
I haven't found Carbide, or the Colts that are bigger than 2 1/8" Does anyone know if larger sizes are made? I would like a 2 1/2 or even 2 3/4...

Thom Sturgill
12-26-2013, 7:57 AM
Here's an idea - start with the largest and drill 1/4", then the next smaller size and drill another 1/4" - continue until you either get to a size that drills easy or you are at depth and then step back up to the largest size. That way each bit gets a center point to start with initially and sides when working back up. More drill changes, but should eliminate some problems.

steve worcester
12-26-2013, 5:52 PM
If you were to do this in one pass, Famag Bormax bits are the best I have used. That size though you are in for $80 or so.

robert baccus
12-26-2013, 10:35 PM
All good advice--I bore 2" starter holes for hollowing to 18" but only in green wood. Starting with smaller sizes works well but nothing hand held please. Whatever bits you buy find a power diamond sharpener, prefereably a disc. Takes about 30 seconds to sharpen steel or carbide fostner bits.

Kelvin Burton
12-27-2013, 1:51 AM
Here's an idea - start with the largest and drill 1/4", then the next smaller size and drill another 1/4" - continue until you either get to a size that drills easy or you are at depth and then step back up to the largest size. That way each bit gets a center point to start with initially and sides when working back up. More drill changes, but should eliminate some problems.

Thom, I think this falls in the category of "great minds think alike" :D I had those same thought going around in my head! Thanks for sharing.

Ricc Havens
12-27-2013, 9:31 AM
Kelvin, as Jamie stated - "after it gets starred the forester guides from the walls of the hole." and as Duane stated "you don't need the center point as long as the work piece is held securely". In the limited experience I have had doing only a couple dozen mugs is as long as I use a slow speed 400-500RPM and feed the bit slowly the foresters work great starting small and moving up in size. The benefit is you are only removing a small amount of wood between each step in size versus removing a whole 2-1/4" worth of wood with just your one bit. Yes, it mat take a little longer due to changing bits but I haven't had to sharpen any of the bit in my cheap $50 Porter Cable forester set yet.

Good Luck
Ricc

robert baccus
12-27-2013, 11:02 PM
Actually the center point is useless for holding the bit centered--it's way too small. The sidewalls hold the bit straight and like above, the whole thing must be very controlled. Try a diamond disc for sharpening these bits--piece of cake.

Kelvin Burton
12-28-2013, 1:23 AM
Try a diamond disc for sharpening these bits--piece of cake.

Robert, I've used diamond hand held "stones" and Credit Cards, are you referring to a powered rotating disc? If so, can you give an example?

Barry Richardson
12-28-2013, 10:49 AM
Just saw this this morning http://www.woodcraft.com/Product/2080329/28217/MaxiCut-Forstner-Bit-2-14.aspx Cheaper than their normal price, Never owned one, but word is they are really good for end grain and easy to sharpen. Think I'm going to get one...

Clarence Martin
12-28-2013, 11:57 AM
4 inch diameter 3/4 inch shank carbide forstner bit is on sale for $510.00 .

robert baccus
12-28-2013, 9:54 PM
Kelvin, HF has some small discs(3"?) for dremel sized grinders. I use 6" lapidary discs from E-Bay in 4 grits--180- 1600 for tool honing and bit sharpening. Very cheap as well. I mounted mine on a HF 4" bench buffer and with 2 shafts I'm able to run 4 grits(back to back). Good luck