What tool to cut baffle holes?

kvk

Member
2008-01-25 4:37 pm
What tool for Cutter baffle holes

I supposed a Jasper Jig is probably the best tool for routing baffle holes for drivers but it's about $40 which is a fair amount if you are only building one pair of speakers.

Are there any cheaper options? Does someone make something like a cheapo adjustable jig for routers?

I do have a router and bits already.
 

EC8010

diyAudio Moderator Emeritus
2003-01-18 7:57 am
Near London. UK
Re: What tool for Cutter baffle holes

kvk said:
Does someone make something like a cheapo adjustable jig for routers?

I do have a router and bits already.

Last Wednesday I made a trammel for my router and cut two perfect circular holes with rebates in plywood without any splintering. All you need is a strip of something reasonably rigid (I used 1/4" SRBP, but you could use aluminium). You screw the router to it, and at the right distance from the cutter, you drill a hole for a bolt to go through the centre of the circle you want, drill a hole that size in your baffle. Then, with great trepidation you gently lower the bolt into the hole in the baffle, switch the router on, and cut a perfect circle.
 
If you are doing anything over 5" the above methods work well.

Hole saws are available up to 5".

What makes the Jasper work is that the center pin goes into
a metal shank and so the router will not pull out of round.

Using a circle cutter with just a pin through wood has not worked very well for me.

Other method not discussed yet is the jig saw with circle jig.
the circle jig attaches and goes for about $7 USD here.
 
Jont,

As I recall Jasper had some complicated calculation to do circles.

Did you center and eyeball the right calibrated hole or use the
Jasper system?

BTW, Jaspers go on deal once in a while and as a set with a larger and smaller one.

I have some better bits now so I may give my small roto tool a whirl at doing circles with it's kit again. The pin in that rig fits snugly into a
certain gauge of T-nut. But I'm still using 4 in speaks so never did a finished circle cut with that rig.
 
I've used this for the last 5 years with no problems at all. Pic shows the jig upside down. Its best used if the target piece is placed ontop of a piece of scrap so you can drill the centre of required hole thru both pieces.

for duplicating holes I find it much easier to cut a template with the jig tool and then just used the template.

Ed
 

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loninappleton said:
Jont,

As I recall Jasper had some complicated calculation to do circles.

Did you center and eyeball the right calibrated hole or use the
Jasper system?

Not particularly complicated. If you use a quarter inch bit, then you just use the correct hole. I've got a half inch, so I had to use a hole an eighth less than required (for outside cuts) or an eighth less than required (for inside cuts).

I did make a mistake in the size of the cut-out (slightly too small), but that was due to measurement not the tool. The second time was much better. And, due to the width of the rebate I had to make 3 passes to do that successfully.

Worth it, I think. I've got the big one, as I'm only using it to cut out speaker holes - I don't do vented speakers.
 

ScottG

Member
2003-02-04 12:23 am
US
Zaph cuts a LOT of baffle holes for driver testing (..and projects). Note his comment here (March 17, 2008):

http://www.zaphaudio.com/blog.html

"I love showing off a nice clean baffle. Once again, I'll say the Sears circle jig kicks the Jasper jig's ***. How obsessive/compulsive am I? When I cut a driver countersink, before I mark and predrill the screw holes, I'll center the driver in the opening using 4 pieces of folded over post-it note. If the post-it note requires fewer than 3 paper thicknesses, I'd call it failure - if for some reason I had to repaint the baffle, there's a chance that the driver would not fit a paint thickness. If it requires more than 5 paper thicknesses, I failed again by making the countersink too large. Luckily, I pretty much nail it with a 4 paper thickness gap every time, as I did in this image. Try that with your Jasper jig.

The "Craftsman Multipurpose Router Guide" is Sears item# 00925179000 and Mfr model# 25179. $18, and 1/64" accuracy... in the right hands with enough practice."
 

MJL21193

Disabled Account
2007-03-10 1:20 am
I use the following for great success!

Starting with my trusty brace and bit, I drill a hole big enough to start my keyhole saw. Once a nice neat hole is cut, I use a combination of marking gauge and router plane to cut the recess.

Piece of cake!
 

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MJL21193 said:
I use the following for great success!

Starting with my trusty brace and bit, I drill a hole big enough to start my keyhole saw. Once a nice neat hole is cut, I use a combination of marking gauge and router plane to cut the recess.

Piece of cake!

But John,

you've had years of practice at doing this and I wouldn't trust myself to saw a straight line without some sort of jig/brace/form to keep me in line.

A man's got to know his limitations (someone said that before I think). And I have lots of limitations but I just try to find a way around them instead of getting someone else to do the work.

Makes for slow progress, but I can say it's all my own work!
 
MJL21193 said:

Starting with my trusty brace and bit, I drill a hole big enough to start my keyhole saw.
Piece of cake!

Nice brace. I haven't seen many, but I've never seen or used a wood one.

I haven't flush mounted any speakers I've built, but they were all larger fullrangers or subs. If you aren't flush mounting, you don't have to be super accurate. I use a rotozip freehand. I've tried their circle guides (both) and they are terrible for thick material. With a skinny bit, you can probably cut freehand circles with your router. Heck, I've heard of some folks freehand routing the recess for flush mounted pincushion shaped drivers.

pj
 
What's a pincushion?

The method I used my first couple tries was:

Cut the driver hole with a hole saw.

Position the driver.

Pilot some holes for the screws

Screw the thing down.

Draw an outline on the surface.

Free hand flush mount with roto zip tool
and 3/8 bit (to make the corners.)

Rotozip-type tool has real high speed and I steadied it as best
I could. Latest job was on the FrankenBIB. Do not go
below about 1/8 in for Fostex. I did 3/16 and it was a little deep.

For jobs like the BIB, be sure to factor the depth of the flush mount
when cutting your stock. I tried to flash mount after a completed build and the driver hit the back after the cut out was made. I got around that and hence renamed the project the FrankenBIB. I'm listening to it now and it's back in service.
 

kvk

Member
2008-01-25 4:37 pm
ScottG said:
Zaph cuts a LOT of baffle holes for driver testing (..and projects). Note his comment here (March 17, 2008):

http://www.zaphaudio.com/blog.html
...

The "Craftsman Multipurpose Router Guide" is Sears item# 00925179000 and Mfr model# 25179. $18, and 1/64" accuracy... in the right hands with enough practice."

My router is a Skil 1810. Anyone know if router bases are standard and the Sears jig will fit?
 
If you already have a jigsaw, just draw the appropriate sized circle and free hand it with the jigsaw. Most speaker bezels will cover up any wobblies off the line. If not, and you already have a router, or roto type tool, then buying a circle cutting attachement is a good investment, seeing as how you're going to have to buy something anyway. (I have the small jasper jig, and like it, but, I wish I had the next larger one.)

Tom.