How to inset Fostex drivers?

[matherp]

Hi all

Can anyone please advise a relative beginner in the woodworking department how to neatly inset Fostex drivers so they sit flush. Why can't they make them round?

I've got the usual tools including bench-mounted or hand-held router but without making a jig by hand or having a dead driver to use as a template I'm stuck.

Any suggestions gratefully received

Best regards

Peter

 

[Ty_Bower]

An externally hosted image should be here but it was not working when we last tested it.

http://s69.photobucket.com/albums/i43/Ty_Bower/Makizou/P1120683.jpg

They don't mind sitting face down on a flat surface. Could you try tracing the outline of the basket onto the face of the baffle, then cut it out with the router by hand? Maybe stop 1/16" shy of your pencil line, then go back with the sanding drum on the Dremel tool to clean it up.

 

[scottmplsmn]

Trace the driver frame outline onto a piece of 1/2" x 12"+/- x 12"+/- mdf using a 1/8" shim between the frame and your pencil. Cut out the opening leaving waste on the cut side of the line. Use a rasp / file to get down to the line. Fit a 1/8" offset template guide to the router base and chuck a straight cutting bit into the router. A plunge router is nice but not necessary. Set the router for a cutting depth equal to the frame thickness. Clamp the template to a piece of scrap and do a trial cut. The advantage is you only need to get the template right once, and then you can do multiples.

 

[Andrewbee]

http://www.exquisiteaudio.com/baffle.html

I should add - make sure your bit is centered to the base of your router, of course it should be but its worth reminding you of.

 

[quiet fish]

You can also, use top bearing bit and make the template opening just 1/32" bigger than the drivers frame.

 

[loninappleton]

I think it was 6 inch or 6.5 below which flush mounting does not accomplish anything. That was the advice from GM, a regular here. So how big of a speak will you be using?

I tried this free hand for the Fostex 127e: did the tracing and tried to steady up to the
line but there is a lack of control.

The system from andrewbee looks to be a good one. There is another and the process is documented in text at a thread called flush mounting the whole story from some time back. Try search for that if you want to make templates. Or I can look for it-- it was my thread but I am lousy at using search on this site.

Let me know if I should go look it up.

 

[chrisb]

there's always the option of having a brilliant CNC operator with a few minutes on his hands to write programs (for both the driver opening and flush mounting rebate) at the control panel, then save them 🙂


Would there be any interest in CNC routed templates for use with pattern following router bits? I currently have patterns available for the 3" , 4" and 6" Fostex drivers.

An externally hosted image should be here but it was not working when we last tested it.

After cutting your driver opening with hole saw or router jig, you drop the driver in place then fit/align the template outside of that. It's probably a lot easier to complete the routing before cabinet assembly as it allows you to clamp the template and work piece securely to the bench - even though you're only removing approx 3-4mm depending on driver, you can't be too secure.

 

[planet10]

Would there be any interest in CNC routed templates for use with pattern following router bits? I currently have patterns available for the 3" , 4" and 6" Fostex drivers.

Chris & i have discussed this and we could certainly do it. Templates could be purchased, or maybe even rented (more complex, but many people likely only need to use the template twice). i would consider that rent be paid to diyA as a donation.

dave

 

[loninappleton]

I have thought about doing this for a long time but don't have a blank Fostex to do the pattern making which I thought necessary.

Though I've studied the procedure over and over since it was printed in Speakerbuilder, I have one question. How does the template get centered properly after the cutout is made? Cutout is made by using the diagonals and finding the center then use a circle jig or hole saw to punch out the hole. How is the template positioned and do you have any pics of the work on your projects for 4" 6" etc? The pattern has to be in a frame and the frame would have to be centered and then properly clamped or screwed in place to prevent wobble. Some kind of registering system as is done in printing with color overlays would be necessary.

 

[chrisb]

I have thought about doing this for a long time but don't have a blank Fostex to do the pattern making which I thought necessary.

Though I've studied the procedure over and over since it was printed in Speakerbuilder, I have one question. How does the template get centered properly after the cutout is made? Cutout is made by using the diagonals and finding the center then use a circle jig or hole saw to punch out the hole. How is the template positioned and do you have any pics of the work on your projects for 4" 6" etc? The pattern has to be in a frame and the frame would have to be centered and then properly clamped or screwed in place to prevent wobble. Some kind of registering system as is done in printing with color overlays would be necessary.

All of my own projects were made with CNC machined baffles, so I don't have any photos of the procedure described below, but I have thought of how I'd go about it.

There was one project on which I free-handed the rebate - even if you pre-score the outline with a veneer knife around the frame of a mounted driver, it's just too easy to mess that up.

There are a few photos of finished projects here:

Meet the Fonkens

All of these (except the solid bamboo plywood, and the edge grain fir cabinets with radiused edges, built by Scott Dunn) were veneered after assembly, and the driver /port slot cutouts hand trimmed.


The template would be either 1/2" or 3/4" MDF, and oversized to allow for clamping, or even screwing to the work surface.

Assuming that you're routing the rebate separately from the driver cutout, and before the baffle is assembled into the enclosure:

- use some spacer blocks for the first couple of steps;
- install the driver and align either by eye (just kidding) - use a T-square to align the screw mounting holes on the driver frame;
- drill pilot holes and temporarily screw the driver in place - it should now be "square" or "diagonal" depending on your preference;
- remove the driver and re-mount "backwards" on the front side of the baffle;
- using either double edged carpet tape or clamps, secure the template to the work piece and bench - it should self-register on the driver frame and bench;
- remove the driver;
- set depth of cut on your pattern following router bit;
- make sawdust , then have a beer

 

[loninappleton]

I followed some of that but how many layers is the pattern?
When using the guide bushings the pattern has to marger than the travel of the bit.
This always confused me with the guide bushings-- that and getting the bit and bushing correct.

Also using carpet tape can be a PITA. From making router bases for both a router and a zip tool, I learned that the tape can pull and skew if used out to the edge. Word of warning to those doing this: any tape should be applied inside the area of any cutting since the bit often does hang up on the tape.

If a guide can be made for little tiny hinges as in the recent Fine Woodworking mag., then this should be replicable with the right setup.

 

[matherp]

All

Thanks for the helpful responses

ChrisB - certainly interested in 3" and 4" if you can ship to the UK and the price is right. I was in Victoria earlier this year visiting the in-laws - beautiful part of the world!

Best regards

Peter

 

[MJL21193]

This always confused me

A year and a half later and you still don't have it?
Time to give up and surface mount the thing already.

 

[rjbond3rd]

Personal attacks are not allowed, Mr. MLJ21193. And that's for your protection. Off to Texas with you.

 

[planet10]

All

I was in Victoria earlier this year

And you didn't come visit 🙂

dave

 

[planet10]

Off to Texas with you.

 

[rjbond3rd]

Somebody warn Ron Clarke 🙂

 

[chrisb]

I followed some of that but how many layers is the pattern?

Obviously I wasn't clear enough - there is only one (negative) pattern for the mounting flange rebate - this method assumes that the main driver mounting hole is already cut.

When using the guide bushings the pattern has to marger than the travel of the bit.
This always confused me with the guide bushings-- that and getting the bit and bushing correct.

I generally avoid using guide bushings as well - the bit shown in my earlier post is a top mounted flush bearing pattern following bit. The pattern is the exact size of your desired result - the only adjustment you need make is for the depth of cut - and since, as noted above, the driver main opening is already machined, you're not worried about calibrating for a plunge.

Also, using carpet tape can be a PITA. From making router bases for both a router and a zip tool, I learned that the tape can pull and skew if used out to the edge. Word of warning to those doing this: any tape should be applied inside the area of any cutting since the bit often does hang up on the tape.

If a guide can be made for little tiny hinges as in the recent Fine Woodworking mag., then this should be replicable with the right setup.

yup, I wouldn't use carpet tape either, but since I've seen it referenced lots of times, I thought I'd include it here. I'd only ever clamp or screw the pattern and work piece securely to bench. It takes far longer to set up the patterns and jigs than it does to route the rebate, but you can repeat all day long with deadly accuracy.


MJL's post referenced above is another excellent method for achieving the same result. Of course you could always follow his (and others') suggestion and simply surface mount them - but I just happen to like the aesthetic of rebated drivers. I do the same thing with the Mark Audio and other round frame drivers - of course access to a commercial CNC router and talented programmer/operator is not a luxury to which all DIYers can avail themselves. 😎

 

[planet10]

Somebody warn Ron Clarke 🙂

Anyone heard from Ron lately?

dave

 

[rjbond3rd]

I was going to ask if you had been in touch with him.