Banjo Hangout Logo
Banjo Hangout Logo

Premier Sponsors

918
Banjo Lovers Online


Nov 29, 2020 - 2:51:34 PM
11242 posts since 1/15/2005

A while back I asked for advice on what kind of bit to use for drilling stoneware pottery. This is pottery that is made from clay that is conducive to very high firing temps (over 2000 degrees) and vitrifies harder than a rock (or at least seems that way). I bought some 3/16" bits from Grainger a couple of years ago (carbide) that seemed to work fine, but now having ordered carbide bits from a different manufacturer they just do not hack it (10 minutes for an 1/8" deep hole).

Are carbide bits different depending on the manufacturer? Do they wear out after one use? Do they require water or oil in the hole that is being drilled?

Any suggestions? I don't mind paying more for a bit that will work. What I don't want to do is pay a lot for a bit that does not work.

PS:  I have Googled this subject extensively and all of them claim that their bit works.

Edited by - BanjoLink on 11/29/2020 14:52:23

Nov 29, 2020 - 4:16:34 PM

nakigreengrass

New Zealand

5502 posts since 5/16/2012

quote:
Originally posted by BanjoLink


Are carbide bits different depending on the manufacturer? Do they wear out after one use? Do they require water or oil in the hole that is being drilled?

 

There's going to be all sorts of rubbish out there in the carbide world...just like all products made these days.  Good quality "Tungsten carbide" drills should be available from any company that supplies professional trades...because the tradies wont put up with rubbish that is parmed off at some cheap hardware stores. 

Coolant or the lack of it is dependent on the material to be drilled....but with ceramics or stone with a consistent grain ( ? )   I would try just using water with a neural rake grind on the bit and a relatively slow speed and feed.   I think this because you actually want to "cut "  the material without causing local heat.  So you are not really using the TC for what it's designed to do...ie..use heat to cut and dissipate heat....but simply because it's a very hard cutting material that will hold a sharp edge.  

With general machining, TC tools don't really "cut " as such but shear off the material creating extreme heat that is transferred to the swaf chips but not so much to the work piece....the TC tool cutting edges are most often negative rake to induce this process....The main properties of TC is that it has a very high melting point, which means the swaf chips come off the work piece very hot, often well above their tempering heat range, which softens the chips and adds the shearing process.......

  That is not what you would want for cutting ceramics...you just want to cut into the grain as carefully as possible with a sharp neutral edge and keep it cool.   A positive cutting edge would not be a good idea either, as that would likely cause problems when breaking through.  So a neutral rake, with a sharp  cutting edge at 90 degrees to the face getting cut would be the way to go.

Nov 29, 2020 - 4:24:40 PM

Iron Paw

New Zealand

437 posts since 11/28/2014

I was a 'potter' and sometimes needed to drill holes in ceramic items (mainly tiles).
Normal HSS drills worked fine for that (and tiles aren't too thick to drill through). The holes allowed me to mount electric clock movements on the back of the tile, and each tile had a unique 'pattern' etc as the clock face.
For the tough stuff you can get diamond core drills.
This sort of thing...

https://diamondcoretools.com/collections/diamondcore-hole-drills

May be the better way to go, and less chance of damaging the work piece.

Edited by - Iron Paw on 11/29/2020 16:26:36

Nov 29, 2020 - 5:51:02 PM
Players Union Member

rinemb

USA

12911 posts since 5/24/2005

Boeing was once huge in wichita.  They developed this lubricant for use with all their metals drilling, teaming, etc.  So much was leaving the plants in lunch boxes, they went commercial with it.  Can't remember where I bought this bottle.  I use it with any metal tapping, drilling, reaming, etc.  Brad


 

Edited by - rinemb on 11/29/2020 17:51:31

Nov 29, 2020 - 7:40:53 PM

11242 posts since 1/15/2005

Thanks guys ........ All very helpful. I'll check and see if our local industrial supply house, Grainger, has tungsten carbide. I may still have the old plastic tube that housed the only decent one I have owned. I want to sat that it may have been made by Clevite or a similar name.

Nov 29, 2020 - 7:47:46 PM

Owen

Canada

7491 posts since 6/5/2011

Fwiw, ThisOldHouse https://www.thisoldhouse.com/bathrooms/21019320/drilling-holes-in-tile has this to say:  "Standard drill bits don’t work on tile, but not to worry. Ceramic tile can be drilled with a carbide bit, while glass and porcelain call for a diamond-tipped bit."

Nov 29, 2020 - 8:07:49 PM
likes this

11242 posts since 1/15/2005

quote:
Originally posted by Owen

Fwiw, ThisOldHouse https://www.thisoldhouse.com/bathrooms/21019320/drilling-holes-in-tile has this to say:  "Standard drill bits don’t work on tile, but not to worry. Ceramic tile can be drilled with a carbide bit, while glass and porcelain call for a diamond-tipped bit."


Thanks Owen.  I have also tried diamond tipped bits without much success, but like the carbide bits there are probably different quality brands.  I think mine were not the highest quality and did not work and were quickly dulled.  I'll take under consideration spending more and getting a better quality bit.

Nov 29, 2020 - 9:19:25 PM
Players Union Member

Brian T

Canada

17592 posts since 6/5/2008

Two things that a Master Machinist told me.
1. The harder the material, the slower the drill speed rpm.
2. Make certain the drill bit tip angle is the correct one for the material.
For example, 90 won't do for stainless steel but 100 cuts like cheese.

Nov 30, 2020 - 3:57:55 AM
Players Union Member

rinemb

USA

12911 posts since 5/24/2005

Yes, Brian, I have to remember (in my laziness) to change the belt position on my sheaves, when drilling wood or metal with my drill press. If I smell burnt or see black on my bit and decide its the bit not the metal, I toss it and cuss. A more modern drill press might making that belt adjustment more easy than what I have to do?
Brad

Nov 30, 2020 - 7:39:52 AM

DRH

USA

586 posts since 5/29/2018

Keep in mind that 'ceramic' covers a spectrum of materials, some of which are used for cutting alloys that can't be cut by carbide. If your carbide drills don't work you may need to use diamond coated tooling.

Ceramics can be cut using water or water based grinding fluids. They are used for cooling and swarf removal, never as a lubricant. The fluid must be applied forcefully for best results. If you can't do this you are better off running dry. Intermittent application of coolant to carbide causes thermal stress fracturing of the carbide. This also applies to diamond coated drills which generally have a carbide substrate.

Ceramic cutting is done by abrasion (grinding) and not shear, as Paul mentioned above. Some ceramic drills actually have a negative primary relief angle - they cut by dragging the tool tip, creating friction.

I've never had any luck with hardware store diamond coated drills. You will need to look at McMaster, MSC, or other industrial supplier.

Edited by - DRH on 11/30/2020 07:40:55

Nov 30, 2020 - 9:50:37 AM
Players Union Member

Brian T

Canada

17592 posts since 6/5/2008

I have no more than a 8" bench-top Delta drill press. 6 or 8 speeds, I use the bottom 2 or 3.
I drill, cut, grind, shape, polish and have a really satisfying time doing all those things.
Wood, stone, copper/aluminum/steel, plastics.
I have a Dremel with a flex shaft, Dremel SawMax and a Rotozip for some other wood carving jobs. Nice but dusty.
I was gifted a Machinist's Handbook. Nothing but hundreds of pages of reference data.
Even a chart of drill bit tip angles for different materials.

Nov 30, 2020 - 12:20:56 PM

11242 posts since 1/15/2005

quote:
Originally posted by DRH

Keep in mind that 'ceramic' covers a spectrum of materials, some of which are used for cutting alloys that can't be cut by carbide. If your carbide drills don't work you may need to use diamond coated tooling.

Ceramics can be cut using water or water based grinding fluids. They are used for cooling and swarf removal, never as a lubricant. The fluid must be applied forcefully for best results. If you can't do this you are better off running dry. Intermittent application of coolant to carbide causes thermal stress fracturing of the carbide. This also applies to diamond coated drills which generally have a carbide substrate.

Ceramic cutting is done by abrasion (grinding) and not shear, as Paul mentioned above. Some ceramic drills actually have a negative primary relief angle - they cut by dragging the tool tip, creating friction.

I've never had any luck with hardware store diamond coated drills. You will need to look at McMaster, MSC, or other industrial supplier.


Good information Doug. I have had some luck with carbide bits, but only one particular brand which Grainger does not seem to carry anymore, or at least I can't find the name that I think it is (something like Clevite).  The diamond bits were inexpensive so I am pretty sure they were not much better than the hardware variety.  I guess I will have to bite the bullet and buy some industrial strength bits.  The holes I drill are small 3/16", so I have not had any luck trying to get a lubricant or coolent where I think it would have any effect.  I wish I could do a better job of describing how hard this stoneware is.  I swear it is harder than most rock that I have ever encountered.

PS:  I do drill very slowly and have found that more effective with all of the bits that I have tried.

Edited by - BanjoLink on 11/30/2020 12:21:44

Nov 30, 2020 - 12:59:01 PM
Players Union Member

rinemb

USA

12911 posts since 5/24/2005

So, I guess a hammer drill is out of the question. Brad

Nov 30, 2020 - 5:57:40 PM

11242 posts since 1/15/2005

quote:
Originally posted by rinemb

So, I guess a hammer drill is out of the question. Brad


Lol ........ I have worked on pieces worth more than $20,000 and am just starting on a piece that was bought at auction for $7,000, so maybe a hammer drill would be out of the question.  I thought maybe Figmo was going to suggest a small dynamite charge??

Nov 30, 2020 - 7:22:31 PM
Players Union Member

rinemb

USA

12911 posts since 5/24/2005

So, why are you drilling holes in 7000-20000.00 pieces of pottery? We collect antique pottery and any turned into lamps (by drilling holes in the bottom) ruin the value. So, I am curious, for sure.
Brad

Nov 30, 2020 - 10:00:04 PM

11242 posts since 1/15/2005

quote:
Originally posted by rinemb

So, why are you drilling holes in 7000-20000.00 pieces of pottery? We collect antique pottery and any turned into lamps (by drilling holes in the bottom) ruin the value. So, I am curious, for sure.
Brad


Brad .... quite often the first thing to break on a piece of pottery (pitcher or jug) is the handle or the neck on a jug.  Almost always the broken handle gets thrown away, so you have to make another handle.  I use epoxy putty.  However, it i risky just attaching the putty to the body, as some of these pieces are pretty heavy and the last thing you want is for the restored handle to break off.  Therefore I use a piece of coat hanger wire as shown in the photo.  In this case, the jug is worth only about $1500 - $2000, but still worth restoring.  The finished handle is shown on the right.  The color looks a little off because of the light, but it did match.

It costs the same to repair a $50 jug as a $20,000 jug, so obviously there is a lot of pottery out there that is not worth restoring.  Incidentally, a storage jar sold last weekend for $364,000 and another for $56,000 ..... both signed by "Dave" and African-American slave whose pottery pieces are in real demand.  One of his pieces reportedly sold for in excess of $1,000,000.




 

Edited by - BanjoLink on 11/30/2020 22:05:58

Dec 1, 2020 - 4:35:21 AM
Players Union Member

rinemb

USA

12911 posts since 5/24/2005

John, amazing work there. I know. I wish I would have known you did this kind of restoration work. We may have a project for you. My wife was an avid collector of 1910 +/- art pottery. Then we went to North Carolina on a buying trip and started collecting contemporary pottery from several regions there, along with face jugs new and old, and other stuff. Used to go back every other year. I got to go to OT jams, and she/we enjoyed the pottery. Again, thanks, I actually knew you would not be in the lamp making biz. Brad

Dec 1, 2020 - 6:28:06 AM

11242 posts since 1/15/2005

quote:
Originally posted by rinemb

John, amazing work there. I know. I wish I would have known you did this kind of restoration work. We may have a project for you. My wife was an avid collector of 1910 +/- art pottery. Then we went to North Carolina on a buying trip and started collecting contemporary pottery from several regions there, along with face jugs new and old, and other stuff. Used to go back every other year. I got to go to OT jams, and she/we enjoyed the pottery. Again, thanks, I actually knew you would not be in the lamp making biz. Brad


Brad .... that's great that your wife enjoys collecting pottery.  I have been collecting for over 30 years .....oh maybe forty ..... and mostly collect pottery made in the Edgefield District of South Carolina from about 1820's to about 1880's.  I do however, collect some upstate pieces made around my neck of the woods and a little bit of North Carolina pottery which is more modern (mostly, but also older pieces).  I have started repairing some of the more modern Seagrove (Jugtown) type pottery in the past year and have enjoyed working on it.  I think my wife actually likes it more than the older pieces we have.  I have a few pieces that will be on exhibit in a major Art Museum starting in 2022.  I'll let you know when that happens.

PS:  I started repairing this stuff because I was too cheap to pay someone else!smiley  Here is a handle and neck restoration I did on a very rare Cheever Meaders (Georgis potter, probably from the 1930's and was Lanier Meaders father) cobalt blue face jug.




 

Edited by - BanjoLink on 12/01/2020 06:35:59

Hangout Network Help

View All Topics  |  View Categories

0.203125