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Need a jig

6481 Views 15 Replies 10 Participants Last post by  bobj3
I have a project and would like input. I need to build a template to assist putting additional vents in the soffit of my house. I plan to use a small trim router to cut a 6x15 hole about every 5 feet. How to hold the template in place while I cut upsidedown. Any input will help.
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JMRagan said:
I have a project and would like input. I need to build a template to assist putting additional vents in the soffit of my house. I plan to use a small trim router to cut a 6x15 hole about every 5 feet. How to hold the template in place while I cut upsidedown. Any input will help.

If you build the jig from 1/2 plywood, it may hold in place using double sided carpet tape. If that doesn't hold you can probably tack it in place with a small nail in each corner.
I had a similar problem. I solved it by assembling a 2x4 "stilt", if you will, to hold the templet. The stilt consisted of 2-2x4's. The 2x4 stilt went from the ground up to the bottom of the soffit where the templet was nailed to the top of the stilts. The stilts where only long enough so that I had to place a sort of shim at the ground level in order to compensate for the unlevel ground. Needless to say I live in a 1 story home.

If I had to redesign for a two story house I would probably try some sort of V-shape armature that would sit over the roof and reach under the soffit where one leg of the V-frame would hold the templet in place. If you use a plunge router you may be able to attach it to the V-frame and just slide the whole V-frame down to make the next cut. I am thinking the frame is made up of two V shapes set on one side. The templet is nailed between the two bottom legs of the frame which is horizontal while the upper legs follow the slope of the roof. I would put some sort of grit material on the part of the upper frame that comes in contact with the roof so that it will grip the shingles. Or maybe just a bunch of nails nailed throught the 2x's just long enought to grab but not puncture the shingles on the roof.

Just a thought. Sounds like an interesting dilema. Good luck.
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I did exactly what you are trying to do several years ago. I used molly screws to hold the vent screens on. The jig I made had a rectangular cut out for the size of the opening with holes around it that matched the screens. Using one of the screens I marked where I wanted the holes for the molly screws. I drilled the holes and installed the molly screws. I then attached my jig with a couple of the molly screws. I drilled a couple of holes inside the corners of the jig and ran the router with a template cutting bit around the inside. I removed the jig and installed the screens. this worked very well for me.
Hi: I would put the grilles on with screws through the holes in the grille itself. The jig could be 1/2 inch plywood and it could be held on with wood screws in the same place as the screws go in the grille, so you won't have anyholes to fill after you finish..
Make a template

Make a template that will attach to the piece being cut out and attach it with screws. Use a bushing or pattern bit to make the cut.
I have a different suggestion that might be too simple. Lightly trace around your grill with a pencil. Mark the screw mounting holes. Remove the grill and free hand the opening. The grill is going to cover it so it wont show. I used a RotoZip when I did my soffit vents. If you are set on using your trim router with a template then cut a piece of 1/4" Masonite to 5 x 14 and attach it with double sided carpet tape. One last tip: Regardless of how you are going to make the cut use a spacer to place between the edge of the soffit and your template or grill. This way they will all line up and you wont be playing with a measuring tape upside down for hours.
I think it comes down to the right tool for the right job.
A router may not be the right tool for this job,just my 2 cents.
I would use a saws-all ,not a jig saw,may not have the room to turn it or you may not want to repaint the soffit and the jig saw will mess up the paint job, soffit work is a base
Any time hold a tool over your head you must take care but the saws-all is made for this type of job not a 13 lb. router or a unpowered RotoZip, most vents are installed in 1/4" / 1/2" plywood without a inside frame and the screw holes are set to the outside of the grill so it can be screwed it to the plywood.
With just a little care you can drill a hole and cut a hole in the soffit and install the vent(s)

But I'm sure you must have it done by now, your post date Feb.2006

Have a good one JMR
Bj :)
BJ, I'm curious to know what you mean by "unpowered RotoZip?" I used my RotoZip with an 1/8" Sabercut wood bit and it cut through the 1"x soffit material like butter. This type of work is what the Rotary saw excells at. Not knowing what brand of trim router JMR has I can't speak to it's ability for this job but my guess is it should work fine. Remember that it takes more power to turn a larger cutting tool so the smaller the cut you are making the easier the job. In a side note I was pleased when Bosch bought RotoZip; I can see this leading to future improvements and more value for your money.
Hi Mike
I call the RotoZip tool,"the bit breaker",works great in dywall but if you put in into a real load like try to cut 3/4" pine foreget it,unless you make 5 or more cuts at the same slot.
I used every bit I got with this junk tool and then I got some more,not smart on my part but you live and learn.

Then if you put in a 1/4" bit, kiss that bit good by because you just burn up a good bit.
I got feed up with it and put it on my Router Crafter with a speed control that works great for small jobs.
Reviews on the Roto-zip ,one of many,some like some don't

break them bits
by wws11 , Sep 23 '00
Pros: handy
Cons: bits keep breaking and high speed

Thought this would be the tool of the century,being able to reach hard trim spots makes this tool handy but..........when it comes to heavy duty like t1-11 them eight inch blades fail.I always buy a pack and use them all,they keep breaking off.Thank god i didn't chuck my jig saw.Maybe quarter inch blades would improve this tool for wood cutting and a 30 20 10,000rpm speed variation would be a great improvement.No it's not me as i was at home depot and found that contractors were having the same problem.I don't consider this product when i do a job and rate poor although i haven;t used it on sheet-rock it could perform well.Until it's improved the roto-zip cord and one speed model sits.


For rough cuts in soft materials like drywall, the Bosch Rotozip tools use spiral blades that can cut in any direction. A jigsaw handle attachment, the RotoZip RZ-JSH (*est. $40), keeps the blade at 90 degrees to the surface being cut. The basic tools range from 5 to 5.5 amps, priced from the simplest RZ01-1100 (*est. $60) to the variable-speed RZ20-4000 Pro (*est. $145) with three other options in between.

Kits add a range of accessories at some savings in cost. For example, the RotoZip RZ20-4000 Pro Cutoff Kit (*est. $145) includes the jigsaw handle, a right-angle attachment and several other accessories. All carry a one-year warranty. You can find more information on the Web site ( An independent review is also available as a $3 download from the Journal of Light Construction:

Bj :)
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I can not help but laugh when I hear about people breaking bits and then blaming it on the tool design. Power tools are not for everyone. Using any tool requires knowledge of the proper methods for safe operation. There is a learning curve as well. Applying too much sideways force on a small diameter bit will cause it to break. This holds true for drill bits as well as Zip bits. Zip bits make very clean shearing cuts. Only a tiny amount of material is removed at a time. As with any cutting tool you need to let the cutting surface perform its task and not try to force it along.
One of the things I've learned long ago, (grand dad taught me this lesson), NEVER force your tool to do it's job. Only leads to broken tools, and or injuries. A roto-zip does sound like the best choice here. If you do choose to use a sawzall, go with a cordless one. If you are working upside down, you don't want to be fighting with a cord being in the way.

Thanks Mike for the info :)

I have used power tools for about 50 years and I can tell when I run into bad design one like the Roto-Zip tool.
Like most tool user, I buy one now and than that just sucks...
Someone once said there is a sucker born every day and they got me on this one and many others I'm sure.
But this is just my 2 cents, if you like the tool use it, I don't like buying bits that snap like pencil lead..
I own a company that sold used tools like Snap-On,Craftsman and many others and I have seen many ,many ,many power tools over the years, I think I will just let this one drop it could go on for every.

But I do thank you for the info :) have a good one.

Bj :)
Bj, I respect your right to dislike a tool. RotoZip is so poorly designed that almost EVERY power tool manufacturer has copied / created their own version of a rotary saw. All of these tools use the same type's of bits: Guidepoint for drywall, Sabercut for wood, carbide for ceramic tile. Bosch, Porter Cable, DeWalt, Makita and Milwaukee are not in the habit of building or selling tools that do not work.
The hook is their infomercial. That tool looks like it cut cut anything. They must really be cutting butter. What a slick ad. -Derek
I Like Mike hahahahaha
If you go fishing and the guy next to is pulling in the fish left and right you ask him what are you using.?
O I made this tool for 10.oo bucks and I'm selling it for 70.oo and I'm pulling in fish by the buckets, and you say I think I will make one too can't hurt maybe I will a get a fish or two .

The buck rules and the ones with the buck makes the rules.

Have a good one
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