Need help with Forstner bit

[Tea Clipper]

Caution, long post follows:

Background:
After seeing the tutorial for a pocket watch on Russ Fairfield's site, I knew I had to try one. I bought a starter kit from PSI and two big blocks of Cocobolo and Bocote. I used a bandsaw to slice a couple of 1/2" pieces off like you would bread from both blocks. Next, I installed the 1 3/8" Forstner bit in my drill press, and after clamping the wood down, began to 'drill' the wood. Actually, nothing really happened. I had to use a lot of force to get it to start cutting. It wasn't long before smoke appeared; however I'm not taking off hardly any of the wood, so if I want to get down 1/4", I'm going to have to make smoke. After going slow, making small cuts by letting off a few seconds after smoke, I eventually make my 1/4" cut. I take the piece out and notice that on the other side is a black mark (that is still bubbleing!) that had burned through matching the location of the center point.

Questions:
1) The above happened to both woods. Does this sound right?
2) Russ grinds down the center point for clearance. What would happen if I just grind it off completely.? Is it really needed?
3) If I need to keep the point, what if I drill a small hole for it?
4) The Forstner bit from PSI is brand new... I have no idea how to sharpen it... so I bought a Titanium Nitrate set (on sale at HF) and it performed somewhat better.

Well, maybe nothings wrong? Perhaps this is what to expect for the two hardwoods, and I'd have an easier time with a softer wood?

Any ideas/advice would be welcome. Thanks!

 

[ldimick]

Is the drill spinning in the right direction?[:0]

I only ask because I once put a table saw blade on backwards and couldn't understand why it seemed to burn through the wood instead of tearing it apart.

 

[Randy_]

There is definitely something wrong; but I haven't a clue. I just bought a couple of kits to make pepper grinders and the associated Forstner bits. I used them in the lathe rather than the drill press; but they worked just fine....not a hint of smoke!! If you have the bits turning in the correct direction, my only guess is that they aren't sharpened properly and are not biting into the wood???

Do you have a sacrificial block of wood under the piece you are drilling so that the tip of the bit won't hit the table??

 

[JimGo]

How old are the bits? If they're old, they may be dull, at least for these woods; don't forget, they're not called hardwoods for nothin'. If they're bits from PSI's starter kit (sorry, not familiar with that set), then they should be sharp, and I'd check Lynn's response.

 

[Tea Clipper]

I double-checked the direction, and the bit is spinning in the correct direction. That was a good idea though...

Also, I'm not going through the wood, only half way, but the tip goes farther which is why Russ recommends grinding it back (but not off). I made the modification on the PSI bit, but not the TiN bit. Although the tip is not going through, it is hot enough in that area to cause a burn mark on the other side.

Thanks for your ideas so far. []

 

[Dario]

I've never heard of DP running backwards nor seen any Forstner bit cutting the reverse direction so I'll vote for a very dull bit. Hardwood or not, sharp bit should eat through them.

Randy might be on something too, about the pilot part hitting the table.

 

[Fangar]

Ron,

If you performed the grind modification to the bit in question (Wasn't clear from your post), it might be that you have done something to alter the bore path of the bit. I have el cheapo forstner bits and they all cut really well, even through hardwoods. Could be also, that you are cutting at too high speed. A forstner bit removes a lot of material at once. Could be that the speed needs to be slowed down a bit. From Russ' article, he drills them on the lathe at a speed around 400 rpm if I recall.

Also if you are having the problem on the cocobolo, that is a very oily wood at times, and has a tendency to clog the bits anyway. Add too much speed and a problem created by grinding the tip improperly, and we might be on to something. Keep us posted.

Cheers,

Fangar

 

[ctEaglesc]

What speed do you have your drill press set at?

 

[wayneis]

Slow your drill press down as far as it will go.

Wayne

 

[jwoodwright]

Forstner bits are different than regular twist bits. Thet cut with the rim and a lifing motion. This is why they can do partial arcs, and overlaps. The center point merely stabilizes the bit.

Feed rate must be slow as well as DP speed.

Was the piece clamped down[?]

Dense wood takes patience and clearing the bit often. Overheating further dulls the bit and it all goes downhill from there...

 

[Tea Clipper]

I have my DP set at 620 which is as slow as it will go. I tried two bits, both are brand new. I made the tip modification to only one of them. The only time it seems I'm making any headway is when there's smoke. I try to take advantage of this, but yes, I'm taking a bunch of shallow cuts. I don't have the piece clamped down, but I do have a rail clamped down on two sides to prevent the piece from turning.

My setup:

<br />

Cocobolo on the left, Bocote on the right:

<br />

Notice the burn mark in the middle of the bocote (the cut looks clean on the otherside, unlike to cocobolo).

 

[jwoodwright]

Ron,
Wow! Are you holding that piece in place with your fingers[?]

Clamping it will stabilize it and allow you to work safely.

You could box it in with two more "stops"...

 

[Tea Clipper]

Well, I've made three of these and the first one I clamped down. But the clamps were awkward, so I made this jig instead. Because it takes so much force to even start a cut, the piece wont be going up and down, and the two rails provide suffiecent stoppage for rotational purposes. A do use a pencil (eraser end) to hold the free corner of the piece when I let up on a cut. Heck No! My fingers are nowhere near the business end!

 

[jwoodwright]

Ron,
Are you drilling into "End Grain" [?]

End Grain is the Toughest Part, Butcher Block Tables are made with End Grain...

If your piece was say 2x2x6 and you cut off sections like bread, you would be using End Grain.

Try cutting a 2x 1/2 x 6 piece (this example) then you would have a piece of Face Grain, and your Forstner Bit would Love You...

 

[Tea Clipper]

John,
&gt;&gt;If your piece was say 2x2x6 and you cut off sections like bread, you would be using End Grain.

That is exactly what I'm doing.

&gt;&gt;Try cutting a 2x 1/2 x 6 piece (this example) then you would have a piece of Face Grain, and your Forstner Bit would Love You...

I have a few other projects to take care of this weekend, but I will try that in a few days. In fact, I had been meaning to try that anyway becuase when I tried turning a piece I had a heck of time with that too! Lot's of tool catches and tear outs. I'll post my results, but thank you John, I think you have the answer. []

 

[Randy_]

Here is a simple thing to do to test for whether the problem is the hardness of the wood. Cut a short section off the end of a 2x4 and try to drill a hole in it using the same technique. Since the 2x4 will be some nice soft pine, if the bit is good, you should get a nice hole without any problem. If not, I would be on the horn to PSI !!

I don't know that it will help a lot but could you take a closer picture of the bit with one shot neing end showing the tip?? Maybe someone will see something amiss??

 

[Rifleman1776]

Originally posted by jwoodwright
<br />Ron,
Are you drilling into "End Grain" [?]

End Grain is the Toughest Part, Butcher Block Tables are made with End Grain...

If your piece was say 2x2x6 and you cut off sections like bread, you would be using End Grain.

Try cutting a 2x 1/2 x 6 piece (this example) then you would have a piece of Face Grain, and your Forstner Bit would Love You...

As I was reading the responses, the 'end grain' question was in my head. Only John questioned it. Forstner style bits are not designed for end grain boring. If you are trying to end grain bore you will have exactly the problems described. Especially in a hard-hardwood like coco. I do a lot of duck calls and bore 3/4" end grain all the time. A brad point is the only satisfactory drill for that purpose. I tried Forstners but had the experience you describe. Go cross grain, slow speed and very slow feed.

 

[Tea Clipper]

Well guys, I made it back into the shop and cut a few more pieces of bocote the 'other' way. Wow, what a difference cross cuts make! Nice little curls came off and while I won't say it was like butter, I would say it was a heck of a lot easier than before. Too bad the grain is not as nice, but at least I learned something about wood. Thanks all for your help, esp. John.

 

[Randy_]

Originally posted by Rifleman<br />...Forstner style bits are not designed for end grain boring....

Hmmmm?? A lot of companies are selling kits to make pepper grinders and they all are selling Forstner bits to bore the required holes. The nature of the blanks is such that the holes will all be end grain bores. I have not heard of epidemic problems making these kits and have to wonder if places like CSUSA would sell a bit that was not "designed" to do the required job??

 

[Rifleman1776]

Originally posted by Randy_
<br />

Originally posted by Rifleman<br />...Forstner style bits are not designed for end grain boring....

Hmmmm?? A lot of companies are selling kits to make pepper grinders and they all are selling Forstner bits to bore the required holes. The nature of the blanks is such that the holes will all be end grain bores. I have not heard of epidemic problems making these kits and have to wonder if places like CSUSA would sell a bit that was not "designed" to do the required job??

I wonder too. Profit can be a powerful motivator. Note my experiences and Ron's after he tried cross grain with same bit. I make a lot of weed pots, vases for dried flowers. There are times I will drill using a Forstner style, on the lathe. But it is excruciatingly slow. I must back out often, there is burning, smoke, chip build up, sometimes the vase cracks from heat build up. Not good. Forstners are not designed to pull chips up and out of the way like a fluted bit does, they just lay there and clog and burn. Either brad points or spoon bits work mucho-mucho better.

 

[Randy_]

I made some wooden caps for my TIKI torches when the cheap bamboo ones became dysfunctional from exposure to the elements. Cut some "blanks" from a treated landscape timber and used the lathe to drill the end grain. No problem of burning, whatsoever, although the material certainly wasn't hardwood. Wonder what will happen when I drill the walnut blank for my pepper mill??

 

[Rifleman1776]

Originally posted by Randy_
<br />I made some wooden caps for my TIKI torches when the cheap bamboo ones became dysfunctional from exposure to the elements. Cut some "blanks" from a treated landscape timber and used the lathe to drill the end grain. No problem of burning, whatsoever, although the material certainly wasn't hardwood. Wonder what will happen when I drill the walnut blank for my pepper mill??

Let's stop wondering. Give it a shot and post results.

 

[jwoodwright]

Randy, looking forward to the results of your Pepper Mill as well. Wife wants on and I don't want to burn up a bit... Post photos if possible, I find they help in new procedures...

 

[Thumbs]

Forstners are made for making flat bottom holes and drilling partial holes in edges or at odd angles to an edge without damaging the surrounding material. If you have to drill a deep flat bottom hole. Do most of your work with another type of bit, then clean out or finish the hole with the Forstner bit.[]

 

[Randy_]

The largest brad point bits I have seen are 1" bits and the largest spade bits are 1-1/2". My pepper mill hardware requires a 1-9/16" bit and a 1-3/4" bit.

 

[Rifleman1776]

Originally posted by Randy_
<br />The largest brad point bits I have seen are 1" bits and the largest spade bits are 1-1/2". My pepper mill hardware requires a 1-9/16" bit and a 1-3/4" bit.

The ONLY advantage Forstner styles may have for this use is the fact that they commonly are available in large sizes. For deep boring, especially end grain, they are the pits.
Check out: http://www.advantage-drillbits.com/woodworking.html
They can provide anything you need. There are deep boring bits called: sleepers, fish tail, three-wing [looks like Forstner but isn't], planator. What they don't have they can make. Not cheap but quality. They have min. order requirements. This might be a group purchase opportunity.

 

[ashaw]

Last year I was make vase out of bloodwood. Used my lathe to drill the hole (end grain) with a Forstner Bit. Set my shop on fire... Lucky I was able to put it out before any damage occured. I had the lathe too high a speed and drill to fast. How I take my time.

 

[woodwish]

I make a lot wood kaleiscopes out of bocote and have used cocobola until I developed a bad allergic reaction to it (that's another story). It requires me to drill 1 1/8" to 1 1/2" holes up to 8" deep through the end grain. I use cheap forstener bits and will drill 100+ without replacing or sharpening. I do them on the lathe quickly and rarely ever see any smoke. The bit gets warm after a few blanks but not too hot to touch. I have found that it works better for me if I give it a lot of pressure for an inch or so, and then clean out the chips. I turn at about 500-600 rpm but through trial and error I have found that making slow progress tends to cause much more heat, I think the friction causes more heat without dispersing it. It also seems that if the wood gets hot from making no progress it seems to get "hardened" for lack of a better term. I would suggest if you have a good 4-jaw chuck and drill chuck for the tailstock to try it on the lathe. If you want to do it on the drill press I would set your depth stop securly, lower the bit until it just starts to make contact, and then really put some pressre on it. 1/4" is not far, it should cut in a few seconds. The heat may have already ruined that bit but a little touchup with a file works wonders. The only wood that ever seems to heat up much is purpleheart, and the toughest wood I ever use is pecan. I think I would have better luck drilling a hole in a brick with that bit than pecan, but it still works with little smoke. Good luck with it, I have thought about doing the same project myself. Post some pix when you finish.

 

[Tea Clipper]

Thanks Ray for sharing your experience, I can second quite a few of your points. I had ordered a chuck last week and should be receiving it friday, so I'll be giving that a try soon. Russ also has a pic showing this method. I think it could help, since the chips/dust would fall away and not interfere with the bit.

I'm still working the bugs out of the process of making these. I had one split down the middle just as I finished drilling the stem hole, so I change the way I clamp the piece to provide better support. Anyway, things of that nature; its a learning process and a pleasent diversion from making pens.

I'll post a pic when I produce one that I'm happy with (which may be awhile...[:I])

 

[Randy_]

Thanks for your comments, Ray. You have confirmed what I have felt, intuitively, about Forstner bits and end grain boring; but could not confirm since I had no first hand experience of my own. I have made some holes in soft wood and my results mirror those that you have reported; but have never tried to drill any exotic hardwoods. Sounds to me like Forstner bits will work just fine in spite of what has been suggested by others.

 

[Tea Clipper]

I wanted to give it another try, so here we go again with a piece of end grain, this time in my new chuck on the lathe:

<br />

Yes, that is smoke pouring out of it!

So, horizontal cutting isn't any better than vertical (drill press) cutting, when it comes to end grain.

...just a sec, let me get a pic of cross grain cutting...

 

[Tea Clipper]

...and here is cross grain:

<br />

Well, not much to look at here, sorry. I was hoping to show bigger cutting chips rather than the dust shown in the first pic. Anyway, this cut a lot smoother, although I have to admit there still was some smoke. I suppose that should be expected considering cocobolo is a hardwood after all, but not to the degree with the end grain. The top picture really doesn't begin to capture what was really going on... I'm not much of a photographer. My poor bit is probably getting pretty dull too with all of the punishment it has been going through! How does one go about sharpening these things anyway?

Thanks,

 

[Randy_]

Ron: That picture of drilling cross grain still looks funny to me?? Did you ever try drilling a hole in a piece of pine 2x4 just for comparison?? I'm still leaning toward a problem with the bit itself??

What speed were you using with the lathe? Does your Forstner bit have the little saw teeth around the perimeter of the bit??

 

[Tea Clipper]

The pics are "live action", or as best as I can do with one hand turning the tailstock advance, and the other holding the camera. [:I] I'm trying to cut cocobolo, the first pic is end grain, the second is cross grain.

Randy, I tried that awhile back (2x4), sorry I thought I posted the results. Actually I used a scrap piece of "Top Choice Whiteboard" fwiw, and there is no comparison. What I mean is, that was like a hot knife through butter.

The lathe is set at its slowest speed (620?) and yes there are little teeth around it. The one pictured came from PSI in their pocketwatch starter set. I also bought a set from HF that is TiN plated (that cuts better too, but doesn't really change anything.)

I don't think its the bit, because that would mean *two* *brand new* bits! Say, how did that peppermill turn out? Were you able to do anytthing with that yet?

I was looking at some coco pen blanks I have, and maybe its my imagination, but these blanks seem to be lighter, more airier (is that a word?), than the rather dense and quite heavy piece of 2"sq. coco I'm trying to work with here. Does cocobolo (or wood in general, for that matter) have a uniform density, or does, say, wood from the base of the tree happen to be more dense than sections higher up? Due to weight compression, perhaps (just guessing!)?

 

[woodwish]

Ron,

I've been giving this some thought and I think part of the problem is the cocobola, it is very dense and oily. But the problem with smoke is really the design of the bit and how it is used. The part of the bit that does the bulk of the cutting (the flat part for lack of a better description) has a edge on it more like a chisel than a knife. You can't really take light fast cuts with a chisel. A really sharp chisel can take slow light cuts but only when hand controlled, if you smack it with a hammer (more like a forstner bit is used - speedwise)it takes a chunk. A forstner bit really needs to work like a chisel to be very functional. If you are just getting light sawdust it is not cutting, it more like grinding away the surface. Grinding build heat much faster than cutting, think about the problems with sharpening tools. From my experience it seems you really need to keep that flat edge sharp with a file, and put enough pressure on it to make it really cut and not grind.

Sorry if this rambled, it's early and I have not had enough coffee yet . . .

 

[Tea Clipper]

Thanks Ray, my barrel trimmer has the same edge and I've been wondering what to use to sharpen that too. Yes, a file is my first thought too, but which one? I'm not very 'tool smart' so would a diamond file be what I want? Actually, there is a Harbor Freight near to where I live. If someone would suggest a part number to look for, that'd be great! Thanks!

 

[Randy_]

Originally posted by Tea Clipper<br />...Randy, I tried that awhile back (2x4), sorry I thought I posted the results. Actually I used a scrap piece of "Top Choice Whiteboard" fwiw, and there is no comparison. What I mean is, that was like a hot knife through butter.

The lathe is set at its slowest speed (620?) and yes there are little teeth around it. The one pictured came from PSI in their pocketwatch starter set. I also bought a set from HF that is TiN plated (that cuts better too, but doesn't really change anything.)

I don't think its the bit, because that would mean *two* *brand new* bits! Say, how did that peppermill turn out...

OK, Ron. I agree that it sounds like the bit is not the problem. In line with Rays comments, I think you should give some consideration to the possibility that you are boring at too fast a speed. My 1-3/4" Forstner bit tech sheet call for a <b>"MAX RPM"</b> for soft wood of 600 and for hard wood a speed of 450. Based on that you are turning way too fast and that would explain the heat and the dust rather than cut chips as suggested by Ray. Do you have a speed recommendation for your particular bit?? Any way you cut way back on your speed to about 300 RPMs and see if that is the problem??

Peppermill: I've got a bunch of other stuff going on right now and haven't had time to fool with the pepper mill.

 

[Rifleman1776]

Sometimes 'smoke' is not smoke but moisture vapors escaping. But, in your case, using a tool not designed for end grain boring, particularly in hard-hardwoods, it probably is smoke. To avoid, you might have to go as slow as 100 rpm. More better, get a different style bit that works in end grain.

 

[Daniel]

Make sure the chips are clearing, if the bit clogs, and your photo looks like it may be. then you have sawdust rubbing against the block not the bit. with my forstner bits I have to back off and clear the chips by hand every 1/8 inch or so. with oily wood like Cocobolo, it would be even worse.

 

[Randy_]

Ron: Here is one possibility.

http://www.grizzly.com/products/item.aspx?itemnumber=h3129