Counterbore 8020 for anchor fasteners (DIY)

[jthacker48]

Why not just use a different style of fastener?

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A 5/16-18 hole has to be tapped into the end of a rail. The pilot hole is already there so you just need to use a spiral point tap to add the threads.

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Then a simple clearance hole has to be drilled in the mating part to use a hex key to tighten the connector.

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Can't get much easier than that. Total outlay for the project...a drill bit and a tap.

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https://8020.net/3680.html
https://www.mscdirect.com/product/details/40214165

The biggest issue that I have with using different fasteners is the cost.  I've already got hundreds of anchor fasteners.  Buying new fasteners would cost me more than having it milled for the anchor fasteners.  In addition, the anchor fasteners are more secure with a cleaner look as well. 

 

[jthacker48]

Little update, I decided to grab a piece of scrap extrusion I had and test my router on it.  I've got a Dewalt plunge router and put in a Craftsman HSS wood bit.  I lowered the speed on my router to it's lowest rpm setting and let her rip.  It made a really clean cut with what seemed like no issue. 

I will definitely need to make a jig that centers the bit as well as controls the distance from the end of the extrusion.  I'm going to go ahead and order a 13/16" carbide router bit and work on the jig while on wait on the bit. 

I added a photo of the cut and the bit I used to the end of the photo album.  I'll definitely take some video when I get the jig finished and am making the cuts that matter.

 

[Cheese]

The biggest issue that I have with using different fasteners is the cost.  I've already got hundreds of anchor fasteners.  Buying new fasteners would cost me more than having it milled for the anchor fasteners. 

Well my thought was that you mentioned 50 holes so that equates to 50 fasteners. So 50 each of #3680 at $2.10 equals $105.

The tooling alone that Ron suggested will run $120-$140 and we still don't know if the Wen is up to the task.

 

[Bohdan]

I'm going to go ahead and order a 13/16" carbide router bit and work on the jig while on wait on the bit. 

Make sure that the router bit is designed for boring straight down, most are not and leave a spigot in the centre that is removed when you move sideways. The spigot may be large enough to stop the plunge.

 

[Michael Kellough]

Depending on the design and use, you might not need the winged washer in Cheese’s post.
Just tap the end of one stick and drill an access hole (for the hex wrench) in the other stick.

 

[jthacker48]

Here is a link to the jig I built for my router. I'm pretty damn pleased with the jig although it looks a little crazy it's very effective. I thought it poetic to make the jig to cut 8020 out of 8020.

I know the router bits I was using were wrong. I was just doing a test as I didn't have the right type of bit. Overall, very pleased but still nervous making the cuts.

video link

 

[Cheese]

Depending on the design and use, you might not need the winged washer in Cheese’s post.
Just tap the end of one stick and drill an access hole (for the hex wrench) in the other stick.

Exactly Michael, that’s how I’ve joined 8020 sections in the past.

The only thing the washer does is to more accurately align the profiles.

 

[rvieceli]

Make sure you can CLAMP everything down so that it CANNOT move. That includes the piece being cut, the whole jig itself and if it were me I’d also lock down the router too. You do not want anything to be able to move.

Sometimes aluminum can gum up on cutters so you may need to use some kind of lubricant.

Ron

 

[Michael Kellough]

Depending on the design and use, you might not need the winged washer in Cheese’s post.
Just tap the end of one stick and drill an access hole (for the hex wrench) in the other stick.

Exactly Michael, that’s how I’ve joined 8020 sections in the past.

The only thing the washer does is to more accurately align the profiles.

I think it’s main purpose is to prevent the tapped profile from rotating.

 

[Cheese]

Make sure you can CLAMP everything down so that it CANNOT move. That includes the piece being cut, the whole jig itself and if it were me I’d also lock down the router too. You do not want anything to be able to move.

Sometimes aluminum can gum up on cutters so you may need to use some kind of lubricant.

Ron

Youth and enthusiasm is a great elixir...however every now and then let's tamp down the enthusiasm with something called experience.

Ron's got this completely correct. Machining metal is completely different than machining wood. If you catch a drill/mill flute in wood you rip out the wood, you duck and it gets flinged it across the room, big deal.  If you do the same in metal you can rip off your arm, bigger deal.

If this were my project, and I felt the need to use a 13/16" diameter cutter in aluminum, you absolutely need to lock down the aluminum extrusion you're working on. And I'm not talking about some puny clamps that are leftovers in your garage. You need something substantial.

Here's my approach to securing the material to the drill press.

The 8020 extrusions would be secured in a very substantial and robust vise. Something along the Palmgren, Heinrich or Kurt line will suffice.

Here's a Heinrich that weighs 40# and is a relative lightweight in the group, that will dampen the movement if something goes awry.

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I'd then remove the Woodpeckers top from my drill press and BOLT the vise down to the cast iron production drill press table with either 1/2" or 5/8" bolts...this is serious stuff.

Also of note, if you've looked up speed & feed tables for machining aluminum, you'll notice that the optimum speed for a 13/16" diameter cutter in aluminum is 950 RPM. Better dial down that router a bit.  [smile]

You'll also definitely need some type of lubricant.

I'm still curious why you're hung up on using a router?

 

[Cheese]

I think it’s main purpose is to prevent the tapped profile from rotating.

Both of those Michael

 

[jthacker48]

To make everyone feel better, I did clamp the entire jig down although the construction and attachments make it damn near impossible to spin as the entire unit is one piece. The piece I'm boring is anchor fastener in 3 places and then surrounded on all sides except one by anchor fastened 8020. Many of the sides are covered by solid pieces of 8020.

In addition, I did use lubes and has the speed of my router down to the lowest possible setting. I'm not sure what rom that is but it's as low as it goes.