# Enlarging holes.....the best method?



## Nogarap (Jan 20, 2011)

Hi, As part of restoration projects on old musical instruments I regularly need to enlarge holes in 1/2" thick wood (usually but not always Maple) The holes are usually approx 7mm diameter and I need to enlarge them accurately to 10mm. Using an electric drill has seen a number disasters as it's basically just too violent to do this as the wood is veneered and this gets ripped up by the drill. Clearly the best way (unless you tell me different) is to use a wood reamer to hand ream theses holes gently to the size I want. However as I've never used this tool before I would be very grateful if anyone out there can suggest exactly what tools I need to buy (and suppliers if possible) and how to use them. I'm assuming that I will need a 10mm diameter straight reamer but as I'm starting off with a 7mm hole would you suggest that I use a tapered reamer intiially to make an opening of 10mm which I can develop? Thanks in anticipation for any help you can give me on this as I'm very much groping around in the fog at present. Regards


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## mdntrdr (Dec 22, 2009)

Glue in a plug, and start over. :smile:


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## Nogarap (Jan 20, 2011)

The 7mm holes are not a mistake, that's the starting point I have to work from. Plugging them would still not help with me having to make the 10mm hole without splitting wood.


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## mdntrdr (Dec 22, 2009)

You lost me. :huh:


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## woodnthings (Jan 24, 2009)

*This?*

http://www.harborfreight.com/t-handle-reamer-66936.html 
Goes to 1/2" or 13mm I believe.  bill


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## Nogarap (Jan 20, 2011)

Okay......how do I enlarge a 7mm hole to a 10mm hole without using a drill? Would a reamer be a better tool to use?


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## Nogarap (Jan 20, 2011)

Thanks Bill, that looks like the sort of thing I need but will I be able to make a straight sided hole with this tool as it tapers so much?


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## tjwoodworking (Oct 3, 2010)

Reamers should work fine. A StewMac medium standard size peghole reamer has a 2 degree taper from 5.08mm to 9.52mm. I have one and it is a well made quality tool. Running the tapered reamer all the way through will get you in the ballpark,

A 10mm chucking reamer can be found cheap on ebay. Used and sharpened slightly undersize reamers ( 9.95mm - 9.98mm) can be had cheap and may be close enough.


Another option, if you can back up the piece and clamp it to a drill press tablle, is to simply cut the hole over with a 10mm forstner bit. On a musical instrument, could take longer to set up than would just reaming them by hand, but you don't have to buy an expensive tapered reamer.

Timothy


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## woodnthings (Jan 24, 2009)

*Nope*

Best you can do is work from both sides, then file the center or drill the center with progressively larger sized drills. The taper will center them pretty well...maybe not perfectly, but close. Can you use a drill press? Can you work from both sides? :blink: bill


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## Nogarap (Jan 20, 2011)

Many thanks to all who have taken the trouble to reply, you have been very helpful. I think I'll try the tapered reamer first then if that doesn't work will try the forstner bit. Cheers.


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## thegrgyle (Jan 11, 2011)

*Maybe this might help.*

I would try to glue in a dowel first , and redrill a new hole, but sometimes getting the right dowl to fit might be tricky, especially if you wood is only 1/2 inch thick. 

You could try using a block of wood as a guide for the forsnet bit.

What I would do is get a nice hunk of hardwood (perhaps maple) and a 10mm forsner bit. Put the bit in a drill press, and drill a hole in the hardwood at the angle that you want your hole to be in the musical instrument that you are repairing. 

After doing so, you can clamp the hardwood guide over the existing hole and drill away. The hardwood guide would help prevent any tear out if it is flush with the musical instrument, and the forsner bit also will help prevent it as well.

Hope this helps... if you need a picture to show you, I might be able to get something put together.... just let me know.

Fabian


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## A-1 Jim (Dec 27, 2010)

A good trick to enlarge holes is to take a thin piece of 1/4" ply and drill a hole in it the larger size you want it to be,then place over you existing hole centering it ,clamp in place then use a forster bit. to drill the larger size hole the plywood will act as a guide.You just have to make sure it's clamped very well so it does not move. On paint grade projects you can just tack the plywood in place with a couple braid nails.:thumbsup:


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## del schisler (Nov 5, 2009)

Nogarap said:


> Many thanks to all who have taken the trouble to reply, you have been very helpful. I think I'll try the tapered reamer first then if that doesn't work will try the forstner bit. Cheers.


You don't have a table mounted router?? You could do the hole with flush mounted bit with a beiring on top and a hole bigger than the 10 mm and use the piece to mount on top of the other hole and use the beiring to ride on the top piece for the beiring and it will make the hole with out tare out ?? Another way. Go to this site Router work shop and ask this question . I have 5 router's and 4 router tables and lot's of bit's i work in inch's and not mm . But i know you will get the answare you want as far as hole in mm and what size for the 10 mm hole ect. http://www.routerforums.com/ i been a member for yrs . good luck


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## cabinetman (Jul 5, 2007)

If the instrument is together, you may not have the depth for the length of a reamer to get to the width you need. You might do well with a hand drill and a new 118 degree split point bit. With the hand drill you can control the bit.












 









.


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## jack warner (Oct 15, 2010)

i would use my router and make a templet, and use a color. but that would have to be made, and you would have to have even more tools.
guess for you that wont work

you could use a router and draw the circle and free hand it.

if this is an old intrament, why are you altering it. that most of the time tosses the value


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## jharris (Jan 8, 2011)

Have you tried drilling the new hole from the unfinished or back side of the workpiece using scrap wood on the bottom to prevent blowing out the veneer?

Jeff


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## Itchy Brother (Aug 22, 2008)

We used what was called pilot drills,or step drill.Check online,I think it would work .


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## Nogarap (Jan 20, 2011)

WOW! Thanks to you guys for all the great ideas. Brilliant!


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## rf58 (Nov 27, 2012)

*drill a hole a litle bigger*

drill the size hole in a block of 3/4 " maple
clamp it over the hole you want to make bigger 
then use it as a guide so your bit don't grab 
it is a good idea to grind the flutes on the bit you use
straight to get a scraping action to slow the aggression down.


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## Manuka Jock (Jun 27, 2011)

Take a scrap of veneer glued to backing wood with you when you go looking for the right bit , and try them out .

Before you drill out the instruments , stick a bit of masking tape over the hole , and see it that stops the tearout .


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## woodnthings (Jan 24, 2009)

*posted Jan 2011*



Nogarap said:


> WOW! Thanks to you guys for all the great ideas. Brilliant!


Problem probably solved by now.....? :blink:


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## cabinetman (Jul 5, 2007)

*Yes It Was*



woodnthings said:


> Problem probably solved by now.....? :blink:


The OP might have solved his problem, but the question and suggested answers may help someone (who hasn't seen this thread) running into that same situation. No harm or foul by bringing it back is there?


















.


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## woodnthings (Jan 24, 2009)

*Not at all*

Just don't expect any response from the original poster. He didn't say which solution worked for him except for this:

Nogarap Many thanks to all who have taken the trouble to reply, you have been very helpful. I think I'll try the tapered reamer first then if that doesn't work will try the forstner bit. Cheers. 

I would be nice to know if that worked for him ..... :blink:




cabinetman said:


> The OP might have solved his problem, but the question and suggested answers may help someone (who hasn't seen this thread) running into that same situation. No harm or foul by bringing it back is there?
> 
> 
> 
> ...


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## against_the_grain (Aug 15, 2010)

My guess is that the OP wanted to replace tuning pegs on guitars or some other stringed instrument. Those tuning pegs often come in different diameters. I replaced mine with slightly larger (better) ones and had to make the original holes larger.

I went with a tapered hand reamer and went about a 1/3 of the way in on both sides and then finished off with a power hand drill. 

It is a little unnerving using a power drill on the head stock of a stringed and delicate acoustical instrument. One mistake and you could ruin the head stock. I had one minor tear-out of the lacquer and finish but nothing not fixable.


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## Manuka Jock (Jun 27, 2011)

woodnthings said:


> I would be nice to know if that worked for him ..... :blink:


I think so too . 
Knowing what the solution to the problem is , removes it from the list of problems .


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## khowald (Nov 8, 2012)

The easiest way to do this is to use a forstner bit, take 7mm dowel hold it in the hole, by hand, center a 10mm forstner bit and just drill it, the dowel will allow you to keep it centered...ken


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## Nogarap (Jan 20, 2011)

Hi, Sorry it was remiss of me not to let you know the outcome. The reamer worked perfectly. Thanks again for your assistance. Best regards.


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## TimPa (Jan 27, 2010)

Itchy Brother said:


> We used what was called pilot drills,or step drill.Check online,I think it would work .


+1 on the step drill. centers on existing hole.


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## EWerner (Oct 14, 2010)

thegrgyle said:


> I would try to glue in a dowel first , and redrill a new hole, but sometimes getting the right dowl to fit might be tricky, especially if you wood is only 1/2 inch thick.
> 
> You could try using a block of wood as a guide for the forsnet bit.
> 
> ...


2X

The trick with this type of re-sizing is centering the drill guide over the exact spot you want to drill.

Good luck. Have not read the whole post but some sort of tuning peg for the musical instrument? I know the violin tuning pegs are indeed tapered.


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