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I would like to craft a slatted ventilation panel/grill like this:

enter image description here

The frame will be made of square aluminium tubes (25 mm side, 3 mm thick). The slanting panes will be cut of 4 mm thick aluminium sheet.

The main challenge here is to affix the panes to the frame in a nice, regular fashion. My intention is to cut shallow (0.5-1.0 mm deep) grooves on the tube sides, apply some metal epoxy (e.g. JB Weld) and slide the panes in the grooves:

enter image description here

The whole point of the grooves would be to direct/hold the panes in the right position while the epoxy hardens.

How do I cut the grooves?

Is there some artful tool that could save me from tedious and error-prone work with a hacksaw and file?

  • Slots like that could be done in a machine shop, perfectly parallel and matching depth & width. Probably worth the cost... – Solar Mike Dec 25 '19 at 10:34
  • @SolarMike That would be last resort. I was hoping to learn about a tool like this but perhaps not that big and clumsy. – Greendrake Dec 25 '19 at 10:49
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    you have a lot of faith in the strength of that glue. – Jasen Dec 25 '19 at 22:42
  • @Jasen I have some indeed. The grill won't be doing any job apart from withstanding wind and rain. Hope that's not too much of a job for that glue. – Greendrake Dec 26 '19 at 1:22
  • pulling or pushing on the centre of one pf those blades would give an extreme mechanical advantage against the glue. but if that never happens it'll probably hang together ok. – Jasen Dec 26 '19 at 1:32
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I believe this can be done in a home-shop environment using a table saw with a carbide tipped blade. I cut 25 mm square aluminum tube often enough without harming the saw. The swarf is a bit of a mess, as one might expect.

The challenge here is to properly index the cuts. As you require 4 mm slots, it means two passes for each slot, along with the need to index for each individual slot.

I think the best approach would be to construct a sled with the required angle and create a stop-block that is secured to the angled portion of the sled with indexed holes into which you'd thread a bolt or screw for more precision.

The requirement for two passes would be managed by a shim on the stop block. One pass for the main cut, insert the shim and make a second pass for the correct width, then relocate the stop block

From Lumberjocks.com: saw sled for angle cuts

The photo represents a simple, flexible saw sled for angle cuts. The indexing stop block could be attached to a longer piece of wood on the right side in the image. Alternatively, one could make the right block indexed to the sled or to the hold-down clamp.

This isn't necessarily the only answer, and is expected to be used as a starting point for expanding one's thought process to reach the goal.

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  • Any saw (table, circular, miter) can cut aluminum. Though they are usually expensive, a blade made specifically for non-ferrous metals is ideal. The hook angle is much lower (typically 5, compared to 15), which makes for a much less grabby cut. One can also use a router if you take incredibly tiny depth cuts. – Aloysius Defenestrate Dec 25 '19 at 15:55
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    For the OP's required 1 mm depth of cut, even an ordinary carbide tipped saw blade will work well. – fred_dot_u Dec 25 '19 at 16:50
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I would use a router with a carbide bit, a jig to hold everything steady, a pin set at a distance to index each slot.

The router would use a guide bushing, the jig would set the angle and length of cut and distance apart with the indexing pin.

The side frame material would be pierced through fully, but not cut edge to edge so as to cut into multiple pieces, but the slots stopped short to keep it all in one piece. A carefully placed pilot hole will start the router bit in the material, using a plunge router to make the cuts. Heat will be your enemy here. you need to let the bit cut the metal without forcing it. It should go pretty easy. Start with material a few inches to a foot longer than you need to use as an extension to help index towards the ends. Through cutting will eliminate the need to make a left and right hand piece.

The slats will be notched on either end, and on either corner to fit into the angled slots. The notches at the corners of the slats will govern how far the sides come into its final dimension. Router

Please note, and you may be aware of this already, cutting metal is a very dangerous proposition. Any slight movement of the material may allow the metal to break loose of the hold that a jig has on it and throw it out with tremendous force. Creating a jig that will hold everything securely at the point of the cutting is crucial.

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How about a miter saw with metal abrasive blade. Set the angle and one sweep could give you the depth and width and you'd be able to see what's happening. Just a thought.

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  • abrasive blades tend to melt the aluminum, resulting in ragged surfaces and gummy blades. A sliding miter saw with depth control is a good option, although only eyeball precision, as indexing would be more difficult. – fred_dot_u Dec 25 '19 at 16:52
  • @fred_dot_u I used them for years and never had that problem, and only .5 to 1 mm deep. – JACK Dec 25 '19 at 17:01
  • except for being very noisy, ordinary cross-cut blades work alight on aluminium if you keep the feed rate low. – Jasen Dec 25 '19 at 22:46

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