Re: [ATM] Preparing to trepan for the first time

[Jarvis Krumbein <jkoptic@juno.com>]

Chris, the cutter you refer to from Grizzly is not suitable at all and
will only serve to give you lots of small pieces of glass.

Jarvis Krumbein
 
On Tue, 14 Nov 2006 16:36:42 -0500 "Chris Dalla Piazza"
<dalchri@hotmail.com> writes:
> Dan,
> 
> You know, I had wondered if I could use one of those.  I was afraid 
> it would
> be too aggressive.  Do you still use the carbo at all or do you let 
> the bit
> do all the cutting while using water?
> 
> We are talking about a ~2" hole in a 6.25" disk.
> 
> It appears that the cutter will cut a V-shaped groove into the 
> glass.  Will
> this slow down the process as it gets further into glass, does it 
> not matter
> that much, or am I misunderstanding the application?
> 
> Will the gap left be too much to glue the core back in after it is 
> cut out?
> 
> Just to be sure, you are talking about one of these:
> http://www.grizzly.com/products/g8964 right?
> 
> Is there anything more to centering jig than making sure you drill 
> the pilot
> hole exactly in the center of the disk (which then acts to center 
> the
> cutting from the opposite side)?
> 
> Thank you for that suggestion, it inspires more confidence than my 
> homemade
> cutter!
> 
> 
> 
> -----Original Message-----
> From: Daniel Fundo [mailto:fundo@bellsouth.net] 
> Sent: Tuesday, November 14, 2006 3:58 PM
> To: Chris Dalla Piazza
> Cc: atm@atmlist.net
> Subject: Re: [ATM] Preparing to trepan for the first time
> 
> <<  Should I grind down the bottom of the edge to make it level 
> rather
> than risk throwing the glass because of unbalanced grinding force 
> or
> will it do this itself as the glass is ground quickly enough?  >>
> 
> Chris,  Yes, there will be less of a chance to throw the hole 
> off-center
> if the bottom is flat to the surface your cutting.<<
> 
> <<  Does the glass disk need to be clamped down or should the 
> cutting
> forces be gentle and balanced enough that I am doing something wrong 
> if
> the disk is pushed around?  >>
> 
> Its always a good idea to secure whatever your are drilling, wood,
> metal, or glass.  I don't know what size we are talking about here, 
> but
> ou can get circle cutters that will cut up to 10".  A jig made this 
> way
> will be centered under the quill, and will guarentee centering when 
> you
> flip the disk over to cut from the other side.  Just bolt the jig to 
> the
> table before you go at it with the circle cutter. (One thing you 
> learn
> the hard way in building stuff is that the time and material used 
> in
> making a jig MORE than pays for itself in ease and accuracy!!)
> 
> <<  Is it realistic to think I can widen the hole cut if necessary 
> using
> something like a Dremel sandpaper bit?  I am thinking of the phrase 
> "You
> can always cut too much but you can never cut too little."  >>
> 
> Unless you have a source for diamond coated sleeves for the Dremel, 
> the
> answer is "NO"  (If you do, let the rest of us know!!! <G>)  Dremel 
> does
> have several SiC grinding stones, but unless you are just talking a 
> few
> thousandths, the enlarging would take longer than retrepanning.
> 
> <<  Is there a better way to center the trepanning bit than using a
> paper cutout?  >>
> 
> Make a jig as I suggested above.  
> 
> Best of luck
> 
> *****-----
> Dan F.
> Memphis, TN
> 
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> 
> 
 
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