How to drill perfect 12mm holes in 18mm Ply?

[Lewis.]

As above, i've tried using an auger bit (I think that's what they're called), but it blows the edges out a little still.  I am using a decent 18V Bosch drill (not professional range though) and a reasonable drill bit.  I am building a home climbing wall so have about 200 holes to drill.  Wanted a Festool drill for AGES so thinking now is a time to get one - C12 probably due to the half inch chuck.  My current Bosch drill has a 3/8 inch chuck so it won't fit a 12mm bit with a straight shank, hence using the auger bit.

Thinking if I get a c12 and some good quality cetrotec bits it will do the job, as festool is good for accurate work right?  8)  Even a CXS if you think it would be up to it?

Any advice would be great, thanks!

 

[ajones]

Hi Lewis welcome to the fog

If you could use a router you would get good results.It would be about the bit rather than the drill,also are you refuring to the face or the back of the material?

A brand new auger bit will give very clean results stay away from flat bits.

 

[Lewis.]

Hi, thanks  [smile]

I am drilling the face of the ply (front).  The drill bit is brand new so i'm a little annoyed that it's not drilling a tidy hole.  I found I had better results by drilling a 10mm hole with a regular bit, then burring it out to 12mm at the front using a countersink, then using the 12mm auger bit after to enlarge the rest of the hole, but that's a right pain in the ass when you have 200 holes to do!  [huh]

Even if my Bosch had a bigger chuck I could use a regular 12mm drill bit which would do a better job I think.  The auger bit seems to tear the ply at the edges of the hole causing it to chip, even with light force, and i've tried varying speeds too  [sad]

 

[AlexThePalex]

To get a 100 % good drill hole you'd best use a piece of scrap wood on both sides of the ply and drill through them. The scraps prevent tear out on both sides. It has very little to do with the quality of the drilling machine, but mostly with the drill bit and the wood you are drilling in. The sharper the bit the better it is,

Sorry to disappoint you, but there is no 12 mm centrotec drill bit, the biggest is 10 mm. Why on earth Festool refuses to make a 12 mm bit I don't know, but many a times have I cursed that incomprehensible decision.

 

[Michael_MA]

As Footstool already mentioned, the use of a router will ensure you have clean holes for each one of them - a 12mm carbide bit will give long lasting performance - its the speed of the drill and the angle precision of the drill axis you should be concerned about - a router ensures 90° degree to the surface and is running at sufficient speed - but be very gentle with the first 1-2mm of each hole - as this will give the best results.

kind regards, Mike

 

[junk731]

Try a 12mm brad point or even better use a 12mm forstner bit both will give clean cuts.

John

 

[neeleman]

Using a Forstner drill might also produce very clean holes.
And you can use them in a normal (accu)drill because of the 8 mm shaft.
You should use plywood on the bottom side for reducing tear out.
Although I only know one company (Famag) that produces a Forstner drill in 12 mm diameter in the Bormax version.
There might be others in the world.

 

[Lewis.]

Thanks very much for the tips guys - I will have a try of some of those technics and report back tomorrow.  I borrowed a forstner bit from one of the carpenters at work so will give it a try tonight (wood work is fairly new to me although i've done bits in the past and would like to learn more about the finer side of things!)  [wink]

Also i'd love a router (FT of course) but they are bloody pricey!

 

[Alan m]

[welcome] to the fog.
adsd already posted. its the bit not the drill. if you cant use the router , a forsner bit will give you the best results. if there is a good point on the forsner bit it will go throughthe material first and allow you to finish the hole from the other side.

 

[tjbnwi]

Try running the drill in reverse, while applying pressure to the bit. Then drill with light pressure to start. This has helped my results in a lot of situations. Other than that, what everyone else posted.

Tom

 

[peter halle]

Whereas you are on the other side of the ocean, you might also want to check out Zobo bits.  They have the option of having a longer center drill that will pierce thru to the other side earlier if you are going to be drilling from both sides.

We are anxiously awaiting our introduction date here.

Peter

 

[Lewis.]

Try running the drill in reverse, while applying pressure to the bit. Then drill with light pressure to start. This has helped my results in a lot of situations. Other than that, what everyone else posted.

Tom

Tom, the lad at work suggested that too, thanks, will give it a shot!  At least withh 200+ holes I can expeiment with a few!  [big grin]

Peter - thanks, i'll check that link.  I'm based in the UK near London.

 

[John Bates]

I represent Famag in the UK and can confirm they will give a very clean cut and accurate hole, certainly best if it is done into a scrap backer. If you need to find a stockist pm me and I will tell you who has 12mm in stock.

 

[DaveM]

Following on Peter's suggestion, if the bit you're using has a deeper centerpoint, one option is to stop drilling the hole just as the centerpoint of the bit punches through the backside surface.  Then drill from the other side, using the small "pilot" hole to center the bit.

 

[MarkusS]

I would go for something that has (much) more speed (rpm) as this Bosch drill.

I'm using both the Famag X3-Bohrmax (with carbide inlays) and Standard-Bohrmax. The product info for the standard Bohrmax recommends (in soft wood):

12 mm - 2.500 rpm
18 mm - 2.000 rpm
30 mm - 1.500 rpm
50 mm - 1.000 rpm

The recommended speed for the Bohrmax X3 is even higher (almost double rpms).

I would guess that your 18 V Bosch does about 1.500 rpm max - which would be far off the recommended speed for 12 mm holes. The C12 - although a nice tool - is rated with only 1.500 rpm too - as are all other Festool-drills.

Options: Go for a Protool Quadrive 18 V (up to 3.800 rpm) or go for a cabled drill like the Protool DRP 13.

 

[MarkusS]

There is a diagram showing the rpms according to diameter

 

[jonny round boy]

I represent Famag in the UK and can confirm they will give a very clean cut and accurate hole, certainly best if it is done into a scrap backer. If you need to find a stockist pm me and I will tell you who has 12mm in stock.

John,

You kept that quiet!

 

[John Bates]

[wink] I joined as I am a Festool owner but I sell tools for a living and I always know best!!

 

[jmbfestool]

What about a Flat bit?  A decent flat bit should give you a good face cut but I would always recommend having material behind to stop tear out on the back regardless what bit you use. 

Unless like mentioned above  your bit you have chosen to use for the job has a point which is long enough to come out on the other side and then you come from the other side but that is extra work and time consuming.   

Be best to have your sheet of ply laid down on another sheet of ply or something like that and drill through! Easier and quickest. 

Dont know how many sheets your drilling or where your drilling the holes but stacking and clamping a couple of sheets should halve the amount of holes your drill as you can just drill through both at the same time.

JMB

 

[Kevin Stricker]

No drill bit will give a clean hole through 19mm ply that is unbacked.  I've built a dozen climbing walls, the key to getting clean holes for the t-nuts is to stack several sheets of ply and drill a hole that does not go through the bottom sheet.  Centrotec, Festool, It will make no difference.  I prefer a corded drill to keep the RPM's up.

If you clamp 4-6 panels together, mark out a 4-6 in grid and drill straight holes using a drill press attachment you will get good results.  Use the bottom  sheet as the template to drill your next  batch.  For your final panel drill through into a 2x4.  A forestner will give you good results but an auger will do it faster and stay sharper longer.

A router with a 1/2" upspiral will give you good results too but you can only drill 1-2 panels at a time.