Another fauxstone drilling attempt ... another problem I need help diagnosing

[ndep]

*** pictures below ***

I just failed at drilling out fauxstone blanks for a majestic pen kit. My strategy was:

(a) reinforce the blank with 1/2" poplar
(b) drill on the lathe using 8 progressively larger bits. The last four bits were in increments as low as 1/64"

I was running the RPM around 300.

The results were not particularly appealing, with a close inspection revealing lots of cracks.

I invite all suggestions. My initial thoughts are focused on the last four drill bits:

(a) Drill bits #5, #6 and #8 are high speed steel brand new right out of the box. They were purchased from DrillAmerica

(b) I have had drill bit #7 for several weeks and have used it 10-15 times destroying trustone & fauxstone blanks. It was this one: https://www.exoticblanks.com/37-64-drill-bit-reduced-shank.html

I noticed that drill bit #7 was difficult to use. Compared to the other three, it seemed to generate a lot of resistance and eventually the lathe just stopped. To extract the bit from the blank I had to resort to a lot of twisting by hand. My guess is that's when a lot of damage occurred but I can't be certain.

My guess is that #7 needs to be sharpened, but I would appreciate the thoughts of those more experienced than me.

 

[Penchant 4]

What is the feed rate? How frequently is the bit being backed out of the material?
These might have a bearing on the issue.

 

[ndep]

What is the feed rate? How frequently is the bit being backed out of the material?
These might have a bearing on the issue.

What do you you recommend?

I varied the feed rate depending on the drill bit. For the first and any that would remove a lot of material, I went slowly. Maybe 1 second feed and then back off for 2 seconds.

For the later ones (which were removing either 1/32" or 1/64" at a time), I felt I could go faster because the drill bit was just slightly bigger than the preceding bit; thus I would feed for 1-3 seconds and then back off for 2 seconds.

Overall drilling time was about an hour.

 

[TonyL]

FWIW, and I am no expert, but I have had more success with Trustone than with the others TS-like products - just one turner's experience.

 

[egnald]

I have used SimStone with success and I have some Tru-Stone but I have not worked with it yet. I have never used Faux-Stone, however, this is my experience with one of the reconstituted stone materials:

I drilled through the SimStone with only one bit (10mm), but it was a carbide bit and I removed the bit after each quarter of an inch or so and let it cool for maybe 10 seconds. I also used BladeCote Blade and Bit Lubricant and re-applied it to the bit three or four times during the drilling process. I think that the lubricant helped the bit run cooler and also the time it took to apply it gave the bit a while longer to cool.

You might try asking Ed at Exotic Blanks. I know they sell Faux-Stone and Tru-Stone both.

Good Luck - Dave

 

[rherrell]

Try squirting CA into the hole after each drill bit, I've made quite a few soapstone pens and that always worked for me. I use CA on the outside too, don't be bashful, soak the you know what out of it. I also use CA when turning, squirt some on after each pass.

If you don't want a shiny CA finish on the completed pen just sand through the micro mesh grits when you're done and it will leave a satin finish.

 

[randyrls]

I have alternate suggestions. Do the cracks happen at the top of the blank? or just the bottom?

1. When I drill any acrylics, I use the cut long, drill short and trim method. Cut the blank about 1/4" to 3/8" longer than needed. Drill the hole just as long as the tube. (Mark the side of the drill bit). When the mark disappears into the blank, stop drilling. Now trim the uncut end to final length plus 1/32". Sand the corners of the blank off to help prevent catches.

2. Most "general purpose" drill bits have a chisel like cutting edge. This is great for soft materials like wood. BUT on hard, brittle material the flute edge digs in and cause the material to crack out. Drill bits for hard, brittle material have a "flat" cut into the flute edge so instead of digging in, the edge "scrapes" the material off. These are commonly call 4-facet bits, or multi-facet bits. I have a full set of these. Cost me a bundle, but rarely to never ruin a blank.

Can you post the exact material you used? Where are you located? Nothing beats seeing some-one do the task.

PS. I drill all acrylics including acrilester(sp?) in one go with the correct sized drill bit.

 

[ndep]

I have alternate suggestions. Do the cracks happen at the top of the blank? or just the bottom?

1. When I drill any acrylics, I use the cut long, drill short and trim method. Cut the blank about 1/4" to 3/8" longer than needed. Drill the hole just as long as the tube. (Mark the side of the drill bit). When the mark disappears into the blank, stop drilling. Now trim the uncut end to final length plus 1/32". Sand the corners of the blank off to help prevent catches.

2. Most "general purpose" drill bits have a chisel like cutting edge. This is great for soft materials like wood. BUT on hard, brittle material the flute edge digs in and cause the material to crack out. Drill bits for hard, brittle material have a "flat" cut into the flute edge so instead of digging in, the edge "scrapes" the material off. These are commonly call 4-facet bits, or multi-facet bits. I have a full set of these. Cost me a bundle, but rarely to never ruin a blank.

Can you post the exact material you used? Where are you located? Nothing beats seeing some-one do the task.

PS. I drill all acrylics including acrilester(sp?) in one go with the correct sized drill bit.

I used fauxstone; I'm located near Boston.

 

[ndep]

I have used SimStone with success and I have some Tru-Stone but I have not worked with it yet. I have never used Faux-Stone, however, this is my experience with one of the reconstituted stone materials:

I drilled through the SimStone with only one bit (10mm), but it was a carbide bit and I removed the bit after each quarter of an inch or so and let it cool for maybe 10 seconds. I also used BladeCote Blade and Bit Lubricant and re-applied it to the bit three or four times during the drilling process. I think that the lubricant helped the bit run cooler and also the time it took to apply it gave the bit a while longer to cool.

You might try asking Ed at Exotic Blanks. I know they sell Faux-Stone and Tru-Stone both.

Good Luck - Dave

I started with Trustone at $23 per blank. After destroying four trustone blanks in a row I switched fauxstone ($9 per blank) in the hopes that the learning process wouldn't be so horribly expensive.

 

[ndep]

FWIW, and I am no expert, but I have had more success with Trustone than with the others TS-like products - just one turner's experience.

LOL I appear to be an equal opportunity destroyer of resin-stone blanks (both Trustone and Fauxstone)!

 

[KenB259]

First a disclaimer, I have never made a Truestone or Fauxstone pen. The only thing I know is Penn State sells special carbide tipped bits for these blanks. Others have probably tried them and can give more input. I just know they are out there.

 

[PatrickR]

I just finished drilling Trustone for the first time. Just for trim rings 10mm hole 3/4" deep. No issues, normal bits, slower than usual with more breaks due to heat and to lube the bit with blade coat.
1 - do you have a way to sharpen your bits? If not look into a drill doctor.
2 - have you been using a lube of some kind? Necessary for anything this hard
3 - the wood surrounding the blank will only hold heat in
4 - the deeper the hole the faster heat is generated.

good luck!

 

[Penchant 4]

What do you you recommend?

I varied the feed rate depending on the drill bit. For the first and any that would remove a lot of material, I went slowly. Maybe 1 second feed and then back off for 2 seconds.

For the later ones (which were removing either 1/32" or 1/64" at a time), I felt I could go faster because the drill bit was just slightly bigger than the preceding bit; thus I would feed for 1-3 seconds and then back off for 2 seconds.

Overall drilling time was about an hour.

I will feed 1/8" to 1/4" and then back the bit all the way out of the material. If the bit is too hot to touch, the feed is too much. When the bit is cool, the drilling can continue. If the swarf starts to load the flutes, the feed is too deep.

I use canola oil as a lubricant/coolant, and wood bits with center point and spurs.

These things work for me. Your mileage may vary.

Good luck.

 

[ndep]

I just finished drilling Trustone for the first time. Just for trim rings 10mm hole 3/4" deep. No issues, normal bits, slower than usual with more breaks due to heat and to lube the bit with blade coat.
1 - do you have a way to sharpen your bits? If not look into a drill doctor.
2 - have you been using a lube of some kind? Necessary for anything this hard
3 - the wood surrounding the blank will only hold heat in
4 - the deeper the hole the faster heat is generated.

good luck!

For #3, thus far the wood has been the only way to prevent the blanks from disintegrating.

 

[tomas]

I can't help but think that heat buildup maybe contributing to the cracking, especially #7, you described it as sticky. I am not sure the poplar surround is of much help since it will compress, dryout with heat, etc. Perhaps HHS.

Just my $0.02, worth what you paid for it.
Tomas

 

[jrista]

*** pictures below ***

I just failed at drilling out fauxstone blanks for a majestic pen kit. My strategy was:

(a) reinforce the blank with 1/2" poplar
(b) drill on the lathe using 8 progressively larger bits. The last four bits were in increments as low as 1/64"

I was running the RPM around 300.

I would start with the RPM. I've been learning how to use trustone and fauxstone lately. I've worked with significantly more fauxstone type blanks than trustone given the huge cost difference.

I drill, on a press, at ~750rpm. I haven't had any kind of cracking issues. I would honestly be a bit worried about drilling at just 300rpm...seems much too slow. I keep my bit cool with just a bit of compressed air...I cool it every few strokes, and I don't seem to have heat problems. The bits stay cool to the touch. I never even stop the press, I just cool the bit while it spins.

I also always use a bradpoint bit, use a pen blank center finder to find the true center of the blank, and use a simple awl to put a starter dimple at that very center. I align the press with the bit in place, and use the bradpoint of the bit to align dead center on that dimple. Oh, and I never use multiple drill bits in succession...I only use the right bit of the right size, once through, and that's it.

From that point on, drill carefully and slowly. In about a quarter inch, back out to clear, repeat repeat repeat. There are two ways to deal with chipout on the bottom.

1. Either cut the blank longer than necessary by about 1/4", draw a line at the proper length of the blank for the given brass tube, set your depth stop to drill past that point but not entirely out of the blank, then after drilling to that point, use a saw of some kind to cut off the blank at the line. That will reveal the bottom hole, chipout and crack free.

2. Put a simple mark on your drill bit that is just slightly below the point where you would drill out the bottom. I use a simple paint pen, as the paint from those is super easy to clean off later. Drill to that line, back out to clear. Then drill very carefullly and very slowly and deliberately out the bottom. Slow, slow, slow is the key. I never have chipout or cracks, and I don't have to bother sawing again (I tend to work in a progressive order, so I chop my blanks up first, then drill them, then paint them, then glue them, etc. and I prefer not to backstep.) This approach takes more care, so if you don't think you can drill this carefully then option #1 is pretty foolproof.

But, 300 rpm, IMO, is just too slow. I feel that would let the bits be more grabby, which could be part of the problem. You mentioned sticky bits...IMO, thats the slow RPM. The other thing is just be slow, careful and deliberate with your strokes.

Also IMO, using a good bradpoint is important. The bradpoint allows very precise alignment, at least when using a drill press, and it gives you a chance to let the drill seat itself properly in the blank before you really start cutting.

One final thought...the hole in your picture, looks to be very large for that blank. There is not much room left around the hole. I think the blank you chose is also woefully under-sized for your bit, and given the kit is a larger kit, I would be very curious to know if you have enough remaining blank for the bushings to fit properly. You need enough remaining material to turn the blank down to the bushing, sand and otherwise finish it...you don't appear to have all that much blank left around your hole. If that was a normal 3/4" blank, I suspect you need at least a 7/8ths. I have turned a couple of Cambridge kits...the caps require a 33/64ths bit. I wouldn't even bother with a 3/4" blank for a Cambridge pen...in fact, IIRC, the bushings overhang such a blank anyway, so 3/4" isn't even viable for such kits.

I suspect part of the problem, aside from the slow bit speed, is simply that you are not leaving enough material around the hole, and with less material the walls will be weaker, and cracking and chipping would be more likely.

 

[PatrickR]

For #3, thus far the wood has been the only way to prevent the blanks from disintegrating.

Okay, but you skip over the the other items. Heat is the issue, dull bits generate more heat and un lubricated drilling builds even more heat. I dont think that that many steps in size should be required. Try two, use lube and go slow and let it cool fully before proceeding. as large a hole as you are drilling, i could see it taking an hour or so to complete. Use your nose when drilling, if you start to smell the material. Stop, it has gotten too hot.

 

[jrista]

Okay, but you skip over the the other items. Heat is the issue, dull bits generate more heat and un lubricated drilling builds even more heat. I dont think that that many steps in size should be required. Try two, use lube and go slow and let it cool fully before proceeding. as large a hole as you are drilling, i could see it taking an hour or so to complete. Use your nose when drilling, if you start to smell the material. Stop, it has gotten too hot.

I'm baffled by the hour estimate here...

I've drilled fauxstone/trustone with bits as large as 33/64ths myself, and it takes a matter of minutes. Most of the time its 10.5mm and 12.5mm. I only ever use the right-sized bit, I don't cycle through bits of progressively increasing size (I tried in the past, always found it was a bit hard to make sure that each larger bit was properly centered, or would drill the same angle through the blank). Now, I do cool my bit with compressed air, neither my bit nor the blank ever get more than barely detectably warm to a lengthy touch, I never smell anything burning and never see smoke, I drill at ~750rpm, and I do agree heat is an issue...but, an hour to drill a blank??

 

[ndep]

I can't help but think that heat buildup maybe contributing to the cracking, especially #7, you described it as sticky. I am not sure the poplar surround is of much help since it will compress, dryout with heat, etc. Perhaps HHS.

Just my $0.02, worth what you paid for it.
Tomas

What's HHS?

 

[ndep]

I'm baffled by the hour estimate here...

I've drilled fauxstone/trustone with bits as large as 33/64ths myself, and it takes a matter of minutes. Most of the time its 10.5mm and 12.5mm. I only ever use the right-sized bit, I don't cycle through bits of progressively increasing size (I tried in the past, always found it was a bit hard to make sure that each larger bit was properly centered, or would drill the same angle through the blank). Now, I do cool my bit with compressed air, neither my bit nor the blank ever get more than barely detectably warm to a lengthy touch, I never smell anything burning and never see smoke, I drill at ~750rpm, and I do agree heat is an issue...but, an hour to drill a blank??

What are you using for compressed air?
And how are you using it? Shooting the air into the hole during drilling, or ...?

 

[ndep]

Here's a summary of the suggestions thus far:

Use a different blank
(a) Trustone or SimStone
(b) A thicker blank

Use a different bit
(a) carbide
(b) 4-facet / multi-facet
(c) PSI stone 5 drill bit set
(d) brad points

Adjust process to decrease heat build up
(a) adjust the feed rate
(b) Use a lubricant: bladecote, canola
(c) make sure the bits are sharp (drill doctor)
(d) use compressed air to reduce heat build up
(e) maybe don't reinforce with wood because that will retain heat

Adjust process to strengthen the blank
(a) Use CA aggressively to reinforce the blank during drilling and turning
(b) use the cut long drill short method

Miscellaneous
(a) increase the RPM

 

[jrista]

What are you using for compressed air?
And how are you using it? Shooting the air into the hole during drilling, or ...?

I have a 20-gallon Husky air compressor, and I just use the air from that. I blow over the bit when backing out to clear the flutes every few strokes. Doing this, the bit simply doesn't get burning hot.

I have not had to resort to any extreme measures to avoid cracking or chipping the blanks.

 

[jrista]

I just drilled some more blanks today. I wanted to stress the importance of careful and slow. When your bit first contacts the blank, wood, resins or stone, I always try to take that very carefully and very slow, with even pressure. I won't use anything other than a bradpoint, and I've gone out of my way to find more exotic bits as bradpoints (the two I have that are not are my V and O bits...those, just seem to be specialty design bits that have a unique flute, and no bradpoint).

The bradpoint helps when you first contact the blank, and for the moments after as you drill into the wood, to ensure that when the cutting edges first contact the blank, that contact is consistent and properly centered. That first contact is also where you want to be very meticulous, careful and slow, as that is the first chance for chipout to occur with resins and stone, and even harder woods in some cases. Don't rush that, give the bit time to fully cut a clean, round hole.

Once you are in, don't rush it. Slow, deliberate, even pressure. In about 1/4", back out to clear the flute, in and out again, in one more then out and cool the bit. You may need to cool the bit more often. I'm actually trying to figure out a way to use one of my air hoses and an appropriate nozzle, with an articulating arm to try and set up a permanent low pressure cooling attachment, that I can attach to the drill press and hook into the compressor to just keep the air on while I'm drilling a blank, as when the bit remains cool, you don't have to take 10-15 minute breaks every 1/2" to let the bit cool just by the ambient air. It should take a couple minutes to get through a blank.

The opposite end of the blank is the other area where you need to be very slow, careful and deliberate. You don't want to just push the bit right through the other side. You need to make sure the bit CUTS out the other side. Chipout occurs when you force the bit through the thin remaining material. When you have an eighth to quarter inch left, reduce your pressure significantly. Progress slowly and clear often. The key here is to let the bit cut through the remaining material, not punch through. The bradpoint is useful here as well, as it will be the first thing to exit the other side, before the cutting edges do. When you see the bradpoint, back off and then very very slowly cut through the remaining thin material at the end of the blank. You should be able to cut through any blank this way without chipout, or if you do get some, it is very very thin slivers rather than large chunks. I don't believe I've ever had a crack from drilling.

Total drilling time with air cooling of the bit should be measured in minutes, less than 10 in my experience.

The one time I do get cracks, are when I assemble pens. As the compression fit parts expand the brass tubes, that seems to be what causes cracking for me. I can have a perfect blank, optimally finished, clear, reflective surface, I can let it cool without any cracking, its done, settled. without issues...and then the moment I compress parts into the tubes, I get cracks. I've taken to filing my tubes thinner before I compress the parts in, and I'm now even going so far as to grind down some of the parts as well, and using a little dab of glue to hold them in place. Because after all the careful drilling, careful turning, careful finishing...its annoying to end up with a cracked pen because the parts are too large.

 

[jrista]

Ok, I just drilled out a PSI Stone blank, turquoise and gold vein. This one was harder than some of the others I've drilled, so I took the approach of cutting the blank a bit longer than necessary, drilling down almost to the bottom, and chopping off the end. I used compressed air to cool the bit. Worked quite nicely in the end. The material definitely seemed harder than the white and black PSI Stone blanks I've drilled before...took a bit more pressure. I also felt in a couple cases where it seemed to "race" just a bit, and that always worries me a bit (Especially when you are near the bottom, as that little race where the bit seems to actively claw its way through the material, is one of the things that can cause chipout on the bottom of the blank.)

Anyway, I took a video of it...but...reviewing it now, I apparently set it just a bit too low (I thought I had it high enough to show the bit in contact with the blank, but I did not.) I'll see if I can create another video showing my procedure. I did capture some photos of the top and bottom after completing the drilling and trimming process, though, to show how clean a cut you can get. Total time was maybe 5-6 minutes to drill through this turquoise and gold blank.

TOP:

BOTTOM: