Forstner bit question.

4826 Views 33 Replies 17 Participants Last post by papasombre, Jul 24, 2017

JOAT

Discussion Starter · Jun 3, 2017

I've never used a Forstner bit, but I have a couple of pending projects where I think one would work on, and save me some time. But don't feel like putting out the money for one, just to experiment. So, I'm thinking of getting one of the Chinese knockoffs, they're only around $7, including shipping, and see if it would work for me.
CNBTR 5.5cm Alloy Steel Forstner Drill Bit Red and Sliver | eBay
Then, if it worked out like I hope it would, I'd be willing to pop the extra $ for the genuine article.

My question is, has anyone here used one of the cheapo Chinese versions? And, if so, how did it work? I don't really want to pop for one, even at their low prices, unless they actually work. Don't even have to work long, just long enough to know they will do the job, and then it can disintegrate for all I care, because the plan is to then get the real thing.

I can actually do without one, by cutting out the pieces before they are put together. But that will take more time, and not be as neat work.

I take back the part about disintegrating. Instead I will give it to my older son. He has been doing a bit of so-called 'yard art', basically welding together a few pieces of what is basically junk. And has found it quit easy to sell them for $40 each. Who would have thought?

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Herb Stoops

· #2 · Jun 3, 2017

It would help if you described what you are using it for also what kind of wood will you be drilling, and on a drill press or hand drill, and what diameter is the hole.
I use Forstner type bits all the time ,but not any like that one. Most of mine are chinese,but do have some better ones. I use mine mostly on a drill press .
On very large holes I use a hole saw ,it is easier on the drill and easier for me to not tear up the back side where it exits.

The one you show is more what I would think of for plumbing or electrical wiring holes , these are more for rough work is my guess. I use the ones that have teeth around the perimeter, not the wing cutters you show. More like These:
HSS Forstner & Saw Tooth Bits - Lee Valley Tools

Herb

Reactions: 4

Stick486

· #3 · Jun 3, 2017 (Edited)

My question is, has anyone here used one of the cheapo Chinese versions?

yes...
short life..
dull out of the box...
elliptical...
point off center...
shank off center..
poor chip ejection...

Reactions: 5

jj777746

· #4 · Jun 3, 2017

Stick486 said:
yes...
short life..
dull out of the box...
elliptical...
point off center...
shank off center..
poor chip ejection...

Good description Stick.I have a set of el cheapo Forstner bits & they are difficult to use with a power drill + what you said,a drill press is the only way to use them otherwise they could break your wrist(s)

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tomp913

· #5 · Jun 3, 2017

3

Here a 1" Chinese bit being used to drill a piece of cherry for the facing of a router edge guide. This is the same bit that I used to drill the door jamb when I was repairing the split. Have to double check, but think I ran the drill press at 800+ rpm, still giving a nice clean cut. The holes in the door jamb were done with a hand drill, don't remember any particular problem.

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harrysin

· #6 · Jun 3, 2017

All except the two un-boxed bits are very low cost Chinese ones and all are Carbide tipped and continue to give excellent performance despite the years that I've had them.

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Cherryville Chuck

· #7 · Jun 3, 2017

I have some cheap ones and also good ones. The best I have are from Lee Valley and work great, even in a hand drill. The cheap ones are okay in a DP but not much good hand held. For details see Stick's comments.

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Knothead47

· #8 · Jun 3, 2017

I have a set from HF. They do a good job but I don't have a call for them a lot like some WWers. Beats the spade bits, though.

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sunnybob

· #9 · Jun 3, 2017

Hole saws work extremely well on soft wood, or hard wood less than half inch thick. Hole saws struggle on deep wood because of heat build up and they will burn the wood in ring marks unless you are very careful, but you can get really big sizes at not much cost.
Forstner bits are the opposite in my experience, Mine tear out soft wood as they go in and as they come out. But a medium sized hole in thick hard wood is what they do best.

roxanne562001

· #10 · Jun 3, 2017

I have a set of the cheap bits they have worked great for my needs. I don't use them every day like some of the pros. I only use them in a drill press. They work great for drilling flat bottom blind holes.

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harrysin

· #11 · Jun 3, 2017

As you can see in this shot, these low cost Chinese Forstner style bits have Carbide scribers which prevent chip-out

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Stick486

· #12 · Jun 3, 2017

to stop that tear out use a backer board...

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DesertRatTom

· #13 · Jun 3, 2017

So, if the cheap bit is being used in a drill press, and the piece is replaceable if it tears out, what's to lose. For a short run, if it works OK then you're done. But if it's a one of a kind piece and not replaceable, or you don't have a drill press, buy a better bit. This string is a pretty good primer on forstner bits.

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sunnybob

· #14 · Jun 3, 2017

I suspect the tear out I get might be because I dont have a pillar drill as such. I have a mains powered drill, held in a very old vertical stand. i think the drill speed might be a bit too fast for the forstner, but the drill has an electronic speed control and if I slow it down any further it has no torque whatsoever.
The forstners I have dont have a full width bar either.

MEBCWD

· #15 · Jun 3, 2017

Theo if you buy the cheap bit as a test you are only testing how well that cheap bit will cut. There are many different configurations on forstner bits, some are really ruff and some polished to the max. The material used in the bits also has a lot to do in how well they stand up to use and how quickly they dull. If you look at the description of the one you posted it says the tolerance for size could be off 2mm, I think that probably tells you what to expect from this bit.

As Herb said "It would help if you described what you are using it for also what kind of wood will you be drilling, and on a drill press or hand drill, and what diameter is the hole." This would give us a better idea of what bits to suggest.

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JOAT

Discussion Starter · #16 · Jun 3, 2017

Yeah, I know I should have said what size and what I wanted them for, but just wasn't thinking about that when I posted.

OK, what I am looking for is preferably a 2 1/2" bit, but the sizes I have been finding are 2 1/8" to 2 9/16", any of which will do. I am planning on making my smallest pig and truck banks into a spare change holder, or whatever you call it, for putting in your pocket change in when you undress at night. These will be my usual, layers of 1/2" plywood glued together, running up. I figure a hold 2 1/2" wide (or reasonably close), and about 2" to 2 3/4" deep will do the job. Drill press only. I'll not be making thousands, likely not even hundreds, but it's one more use for small pieces I would probably toss otherwise.

I've been looking some more on evilbay and Amazon, for toothed bits, and figure I can get a decent bit, in the size area, I want for around $20, or even a bit less. Definitely staying away from those really cheap, as in cheap made, Chinese bits.

Thanks guys, been a huge help.

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tomp913

· #17 · Jun 3, 2017

As was mentioned above, if drilling in 1/2" plywood you should be OK - but use a backer board to eliminate tear-out on exit.

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Nickp

· #18 · Jun 3, 2017

Theo...check Ryobi's sets...Homedepot and other places...even Rockler...

Don't know if they sell individual bits.

If you want real cheapo and little quality, check Harbor Freight...but beware...

Whatever you buy, look for it to have wings to start the cut cleanly...otherwise you can throw the wood out with the bit...

Good luck...

woodknots

· #19 · Jun 3, 2017

Theo

If you're making "spare change holders", wouldn't you want more of a dish shape so you can scoop/slide the change out? The forstner bit will create a flat-sided hole which means you'll have to actually pick the change out or tip the holder over and it'll be more difficult. I would think a dish cutting router bit would be more suitable for this operation, if you have one.

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greasyfingers

· #20 · Jun 3, 2017

Up until a month ago I've never used a forstner bit. Now that I have, I'm hooked. I picked up a 1" diablo from HD and was a little hesitant. I was suprised with the finish and tight tolerance. Drilling through 3/4" birch ply with a hand drill gave me a 1.002" hole. I had a sacrificial board under my material and had no blowout. Before this I drilled over 50 7/16" holes with a standard wood drill bit. The holes are rough and have a ton of tear out. I really wish I did them with a forstner.

Sent from my SM-N910V using Tapatalk

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