Help me not destroy everything and cut my fingers off!

[loninappleton]

The Bill Hylton book Router Magic I bought after taking it out of the library numerous times.

Title of the book aside, it shows how many useful jigs can be made with simple materials all based on geometric principles, how to make both square and round sub bases and calibrating these things for use.

 

[chrisb]

So chrisb, you meant to say that this trim router would get burned out by cutting more than a few speaker mounting holes in 1/2" MDF?

a cheapie little trim router like this one, quite likely yes - but bear my comments in the context of my workplace for the past 20 years - a commercial millwork shop that spends well over $10K on new hand power tools, router bits, saw blades and resharpening annually

loninappleton, Years ago, I did quite a few cuts with a jigsaw. I used a nail and a string to draw the circle to be cut out, drill a pilot hole and drop in the jigsaw blade. Follow the line. It worked, but there were lots of meandering imperfections. Very difficult to stay right on that line without wandering off here and there. But like you said, it gets covered by the speaker frame.

I could then use the trim router with a roundover bit along the back of the cut, to give the driver "breathing room" (as per Mark Audio recommendations).

The problem is with a small circular hole. I felt like I was trying to bend the jigsaw blade into the line. It did not feel safe.

The hole I'd need to make for Alpair 7 would be 4-1/16" (103mm). Do you think with that Starrett blade you linked to that it would be possible to make a small hole like that with a jigsaw?

Thanks again.

--
PS - My jigsaw is a Black & Decker "Basic Jig Saw" (single speed) that I've had for something like 20 years.
--

I quite love the 7.3 and have built dozens of enclosures for them - but am in the fortunate situation of usually having access to a CNC router, or in worse case scenario, prepared templates and production routers such as those described earlier ( PC690, 890 the very nice Bosch and commercial grade Black & Decker/Dewalt, etc).

This driver does require a fairly small through hole, and has a generous enough mounting flange that if you're not concerned about recessing for flush mounting careful slow work with a jig saw might work, but I'd really recommend the router / jig , or either a hole saw and drill press at lower speed, hand held corded variable speed electric drill.

In the case of drill and hole saw it's even more crucial than with routers to securely clamp down the work piece on a sacrificial board - run the drill at low speed to score the outline of cutout, then drill a couple of through holes inside that line to allow for clearance of chips and dust - reducing the chance of burn. Don't run the drill at full speed on a larger hole saw - one snag and you can easily sprain your wrist at the least, and hole saw blade tips are neither as hard nor stay as sharp for as long as carbide router bits, and can very easily burn material at higher speeds.

If on the other hand you want a tidy rebated flush mount, then repeated passes with either the Jasper jig or a shop made compass jig for the router are the best options for hand machining.

 

[ODougbo]

Morse makes a 5 -1/2" might be too big - might be perfect. You'd have to borrow and arbor from somebody if you're on a tight budget (any electrician).

btw, if it is good size for your driver, use it for your job and put it up on the swap meet page (or ebay it).

http://www.amazon.com/MK-Morse-AV88-2-Inch-Bi-Metal/dp/B000E8FP7Q/ref=pd_cp_hi_0

 

[ODougbo]

Also, no one mentioned using a flush bit with a 1/4" plywood template (yes you would still have to cut a perfect hole).

This is also a good way to make a hole bigger in an existing box.

Steps:

drill hole in 1/4" plywood; coordinate location so there are places to clamp.

place template over board/box clamp down

if there is no existing hole - this is a good time to use jig saw - stay well within the circle

start making passes and flush cut perfect hole

I see some have said you could use a bigger router, I would agree to that. They are easy to come by: ebay, tool shows, I've been know to stop at pawn shops and make a deal now and then (they often have power amps)

The base on the router shown is pretty small - that's going to hard to use; main reason recommended the Bosch, huge safety base.

btw, This little trim bit was 2 for $5 at woodworking show

 

[AmadeusMozart]

The base on the router shown is pretty small - that's going to hard to use; main reason recommended the Bosch, huge safety base.

About 2 years ago we bought a new house and I needed to make some alteration in the kitchen: a ventilation hole needed to be enlarged..... The only way I could do it was using a trim router and I used a Makita for that.

That thing is dangerous - the base is just too small, it is ONLY good enough for what it is designed for: trimming laminate / veneer. The router nearly twisted out of my hands and made an ugly cut (fortunately out of sight and well within the margin of errors). After the job was finished it went immediately onto the local auction website - I wanted it gone before I would injure myself with it.

It is good to be afraid - almost all accidents happen because people under estimate the danger and do not respect the risks. One thing I learned too late was to make and use jigs as much as possible. And if you do more than a single job then you'll soon discover that you spend far more on router bits than on the router itself.

It is the one tool that I would not want to do without, I do not even need a jigsaw. A drill (press preferably but it can also be one of the jigs that one uses for holding a power drill), a skillsaw and a router. I made a sliding table for the skillsaw (another jig I would not want to be without) and made a circle template of plexiglass for the router. Router jigs are made out of MDF, mostly 3/16".

 

[ODougbo]

Well swap a story with you - I had 3hp Makita.....I put a huge 1/2" round over bit in it, I'm thinking now it wasn't a router bit. When I turned the router on, the bit flopped over, I couldn't hold on to it, it jumped on the floor and ran around the room like the Tasmanian Devil - vertical! (my voltage runs high here 125v - 250v across both feeds.)

Thank goodness the Makita had a good strong chuck! That saved my neck and a trip to the EM room.

 

[rongon]

Hi everybody.

Well, your assorted horror stories convinced me. I took the router back for a refund.

So I'm left with my trusty jigsaw. I saw that there are a lot of blades available. Your comments have helped me understand those a bit better.

I found a few saw blades that are labeled for cutting curves in wood. Some are 20 teeth per inch, others have less, maybe 16 TPI. Do you think I could cut a 5.5" diameter round hole with something like that with a 2.2A single-speed jigsaw? Or do I need to look for a bigger, stronger, adjustable speed jigsaw too?

I marked out the slabs of 3/4" MDF I'll be using for the baffles. Is a basic compass a pretty good tool for drawing the circle on the boards as a guide for sawing? Or should I use a nail with a string tied to a pencil? Or is there a better tool I should use?

I have a friend who has a big, heavy and old floorstanding drill press. For the 4-1/16" holes for the Alpair 7.3 do you think I'd be able to use a 4" hole saw? Do those cut a little big in MDF, or spot on?


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[ODougbo]

I think its good you took it back, need the next size up.

Also they are selling sanding drum kits cheap now - this will come in handy:

http://www.amazon.com/26-Piece-Sand...8&qid=1343257509&sr=1-4&keywords=sanding+drum

 

[rongon]

they are selling sanding drum kits cheap now
http://www.amazon.com/26-Piece-Sandi...s=sanding+drum

Thanks, but how do you use those? In the drill press? Boy, you're making me feel like a real newb...

Can be used in a handheld power drill to sand edges, etc?

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[loninappleton]

Yes stick with the jig saw. String and pencil are hardly reliable. But the plate of the jigsaw could be attached to something like plexiglass.

What I've done is go to the local glass store and just ask if they have any cutoffs. I did this and they didn't charge me-- the first time. Anything that's going in the 'broke box' they shou;d just let you have. You won't need a very large piece. An extension can be used to cut a large arc.


Definitely use the drill press if available. You can get a hole saw from the Morris company that would be an exact measure. Morris and others are handled at all hardware stores.

 

[ODougbo]

You have access to a drill press

Yes the sanding drum goes in the drill press and make quick circular passes - free hand or you can add some scape wood and make up a temp sanding station.

Now that said, I use these, have for years, cut a perfect every time, set up is only a few minutes. This can only be used in a drill press:


Amazon.com: General Tools 55 Heavy Duty Circle Cutter: Home Improvement

 

[AmadeusMozart]

Jigsaw is fine. Actually you do not even need a jigsaw: you could drill a series of holes, break it out and then file/sand it to size.

With a jigsaw get a blade with large teeth, otherwise if you make the cut one side of the hole may finish up larger than the other side due to having to force the blade around the curve. Depends also on how good the jigsaw is square to the material.

If you file and sand it to size: First use a rounded rasp and then when nearly there finish off with sanding. Take a plastic pipe slightly smaller than the hole and wrap the sandpaper around that.

Just in case: have you thought about hiring the tool for the one-off job or even ask someone else to cut the hole for you? And big holesaws are not exactly cheap.... personally I feel a router properly used would be safer at that size.

 

[awkwardbydesign]

Use these blades for circles.FAITHFULL T119BO JIGSAW BLADES FOR CURVED CUTS OF WOODS (x5) - BOSCH FIT | eBay

 

[ODougbo]

If you have a drill press, spend the $25 bucks on a wing cutter, you can cut 100 -200 holes with it.

They make a smaller one, the model 55 is worth the extra $10.

A drill press is worth its weight in gold for a speaker builder.

 

[ODougbo]

btw..save the "holes" they come in handy later for finishing. You can screw them back in with a scrap piece of wood.

 

[TheGimp]

5-1/2 is closest in standard hole saws from Lowes, like these LENOX Bi-Metal hole saws.

Product | LENOX ToolsLENOX BI-METAL HOLE SAWS

I used the 4" one and opened up the resulting hole for the FF125WK. A router with a 1/2" round bit works great to open up the back of the hole.

 

[rongon]

You have access to a drill press

I guess that's a good thing, huh.

Yes the sanding drum goes in the drill press and make quick circular passes - free hand or you can add some scape wood and make up a temp sanding station.

Now that said, I use these, have for years, cut a perfect every time, set up is only a few minutes. This can only be used in a drill press:

Amazon.com: General Tools 55 Heavy Duty Circle Cutter: Home Improvement

Hmmm.... I see. How does that work? You drill a hole in the center of the circle, and there's this blade that does around the circumference? How does that cut through 3/4" of wood or whatever? I can't figure it out by looking at it.

Thanks for the help thus far.

 

[rongon]

OK, you suggested this circle cutter in a drill press (General Tools model 55):
Amazon.com: General Tools 55 Heavy Duty Circle Cutter: Home Improvement

Will this work? (General Tools model 5B):
5 In. Circle Cutter-5B at The Home Depot

 

[ODougbo]

I have some of the smaller ones, they are okay; won't last as long. The blade is much smaller vs. the larger model.

(The smaller one are good to 3" - 4")

You'll like the 55, (well made, heavy); they have been around forever........

Don't forget to flip the board 1/2 way thru!!

 

[chrisb]

I have some of the smaller ones, they are okay; won't last as long. The blade is much smaller vs. the larger model.

(The smaller one are good to 3" - 4")

You'll like the 55, (well made, heavy); they have been around forever........

Don't forget to flip the board 1/2 way thru!!

and run a fly cutter like this at lower speed than you might do with a 1/2" twist drill bit, and securely clamp work piece to drill press work bed