It's called a log tenon and you can get a cutter set here
Lumberjack Tools 1-1/2" Home Beginner's Kit (HSBK1) https://www.amazon.com/dp/B008RZ6TKU/ref=cm_sw_r_u_apa_glt_fabc_JF5A775XGFSWH4P2PKS8?_encoding=UTF8&psc=1
They make both. Ones like these have the countersink bit wrapped around the drill but that you can slide up and down using the included Allen wrench to automatically countersink once you’ve drilled your desired depth, all in one pass.
And ones like these are for using after using a normal drill bit. Each have their own use cases.
-Do I need a primer to paint MDF?
Yes
-Should I use glue or screws? Either way, what glue and what screws?
Depends on how much weight your looking to hold. Since I'm paranoid about stuff falling apart, I always pre-drill with a countersink drill bit (non-affiliated amazon link here), glue up, and use Deckmate Deck Screws to secure it.
The glue will hold, and the screws will secure it in place.
I would suggest priming/painting before assembling. Its hard to get into those inside corners once everything is put together.
The best part of MDF is its relatively cheap, so if you make a mistake, just start over and learn from it.
I would also HIGHLY suggest using a respirator (you should use one at all times when working with wood) and setting up some sort of dust collection. MDF is very very messy and can pretty much be like powder, especially when/if you use a router.
It looks like you were driving the screw too deep so that the V-shaped head was causing the wood to split. The fix for this is to countersink the hole so that the head will sit flush with the wood. They have two in one bits that will predrill and countersink at the same time for speed, otherwise you can buy just a countersink bit and drill the pilot hole separately (pilot hole first, then put tip of countersink in the pilot hole to have a perfectly centered counter sink).
Alternatively, you could use panhead screws that won't sink below the wood.
Center punch and/or small pilot hole.
In a rough material like OSB its really tough to get an accurate pilot hole - the screw or bit will want to wonder into the nearest crevice in the surface of the wood.
I would suggest trying out self centering drill bits. You stick up what you want to screw in (gate latch or whatever) and the bits will self center in the hole to give you a centered pilot hole. I use them all the time for mounting shelfs and brackets and whatnot, and they work great.
Carbide tipped countersink, put what ever bit you want in it, ballbearing non marking depth stop. Cuts super clean in wood, aluminium or steel, easy to take apart and sharpen the carbide.
I just drilled some holes with a Vertex frame to a island top that I bought from Home Depot. I got my frame centered on the top and don't forget to account for any peripherals that you plan to attach to the bottom of the desk.
I used this self centering drill bits after I setup my frame and left it as "template". Then it's less measuring to take place and can be used as a pilot hole.
I took the hole drilling a step further and used EZ Lok threaded inserts so I can bolt my frame to my top. It's not necessary but something I chose to do.
Using countersink bits like these will make your process go sooooo much better. You can adjust the length of the stickout of the drill bit using the set screw, and make a small recess for the head in the top of the wood so you don't split it, or strip the screw trying to get it to sit flush.
Some screws and some materials are conducive to screwing in screws without predrilling, but most are not. 90% of the time you should be pre-drilling holes for the best results.
Amana Tool - (55227) Carbide Tipped 82° Countersink with Adjustable Depth Stop & No-Thrust Ball Bearing, 3/8 Dia x 1/8 Drill
Digital Caliper, POWERAXIS Vernier Calipers Measuring Tool 6 Inch / 150mm, Digital Micrometer Electronic Caliper Set with Large LCD Screen Inch/Fractions/Metric Conversion (Black) https://www.amazon.com/dp/B0887X9NGT/ref=cm_sw_r_apan_glt_fabc_2631F6GEKD6S28GW4B2V?_encoding=UTF8&psc=1
A marking knife is a great tool, as well.
These carbide tipped counter sinks are fabulous! Amana Tool - (55227) Carbide Tipped 82° Countersink with Adjustable Depth Stop & No-Thrust Ball Bearing, 3/8 Dia x 1/8 Drill https://www.amazon.com/dp/B00BJFK6N6/ref=cm_sw_r_apan_glt_fabc_JSM3WBX78CAAQVKQH3PM
You can check some of my posts for how looks as a finished product put together, but may not be super helpful. I used the below but wireless interference th a few hand twists.
Countersinkcountersink bit
oh and if you care enough, you can clean up the pin holes and countersink them. Ive done this on all my builds and it looks so much better. 1/2" countersink drill bit, just lightly hand twist a few turns and you're good.
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I use a special tool, and a technique.
Drill and attach one screw, then the second, and so on.
I use a tool called a Vix Bit, but there are knockoffs now. I have a full set in various sized. They ensure that the screw hole is centered in the hole for the hardware. Here's the Bosch version - https://smile.amazon.com/Bosch-Clic-Change-Self-Centering-Assortment-CC2430/dp/B0000TZX1M
If your box is grounded you've got nothing to worry about, when you screw in the dimmer the screws will act as grounding jumpers but only if your box is metal which you mentioned it is. You may also, for reassurance, tap a hole inside the box with a hole taper and screw a copper pig tail with a green screw where you taped the hole.
Taper
Klein Tools 32239 Drill Tap, 10-32 https://www.amazon.com/dp/B019874Q1E/ref=cm_sw_r_apan_glt_fabc_KTM07VA50R5SSPFQS3S5?_encoding=UTF8&psc=1
Pig tail
Ideal 12 AWG Solid Grounding Pigtail with Screw, Green (50-Pack) https://www.homedepot.com/p/Ideal-12-AWG-Solid-Grounding-Pigtail-with-Screw-Green-50-Pack-30-3392R/202894316 SKU# 202894316
If i were you i would go with the Chamfer tool.. Your going to get a better look than trying to do it with an Exacto knife.!!! I recently posted on this very issue.. Check it out.. But here's the Amazon link for the tool Its $9 and you can use it on your next builds. https://www.amazon.com/gp/product/B000F3SI2O/ref=ppx\_yo\_dt\_b\_search\_asin\_title?ie=UTF8&psc=1
Make you're you predrilled, especially if you're withing 3" of an end of a board. Get yourself some tapered drill bits with countersink heads. https://www.amazon.com/DEWALT-DW2535-Piece-Countersink-Assortment/dp/B0000225OU/ref=mp_s_a_1_4?crid=77HI6JW6BK6E&dchild=1&keywords=tapered+drill+bit&qid=1631361566&sprefix=tapered+d&sr=8-4. They are game changers.
Suggestion: get a drill that predrills and counter bored the hole so the screw ends flat or optionally below the surface.
Similar to https://www.amazon.com/Snappy-Brand-Quick-Change-Countersink-Proudly/dp/B000XXZME8
Cheaper versions exist
Oh that’s ezpz
Depth Stop Drill Bit, 18 Piece Drill Stop Collar Set Positioner Ring and Hex Wrench (3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm, 16mm) https://www.amazon.ca/dp/B07W4JHXR6/ref=cm_sw_r_cp_api_i_D3BND8RMK1DBX7K30PD1
I have similar depth stops to these, they work good. I use tape too though, depending on how many holes I am making
You would just need to use a countersink bit to make the screws sit flush or a little bit into the fan.
https://www.amazon.com/Bosch-CST1-Titanium-Coated-Countersink/dp/B000F3SI2O
My favorite bit, use it every day-
https://www.amazon.com/dp/B00BJFK6N6/ref=cm_sw_r_cp_apa_i_jg.qFbSCTFJQ5
Example 3/8 plugs to fill countersink holes. <Match width of the bit and general color of the wood>
https://www.amazon.com/dp/B00INI69EC/ref=cm_sw_r_cp_apa_i_Ch.qFbYD8JYPP
I mean a combo pilot/countersink. You drill once and get a pilot hole through your board and into a (usually edge on) board below.
Like these:
https://www.amazon.com/Snappy-Brand-Quick-Change-Countersink-Proudly/dp/B000XXZME8
If you really struggle, you could use a self-centering drill bit like in the link below. You don't need to mark drill points, you would hold the bracket against the wall, allow the self cenetring mechanism to align the drill bit for you, and then drill. https://www.amazon.co.uk/Bosch-CC2430-Clic-Change-Self-Centering-Assortment/dp/B0000TZX1M
A miter saw will definitely make projects easier. Depending on budget I'd shoot for a 12" if you're not having to lug it around a job site. If you have a bigger budget, look into sliding miter saw. Opens up more possibilities. Also, one of the cooler diy tools to have that is pretty inexpensive is something like this https://www.amazon.com/Bosch-Clic-Change-Self-Centering-Assortment-CC2430/dp/B0000TZX1M/ref=sr_1_2?ie=UTF8&qid=1535570856&sr=8-2&keywords=vix+bit&dpID=41YxEFIPn6L&preST=_SY300_QL70_&dpSrc=srch Makes putting screws in correct places a lot easier
I've used these for a few years with great luck and durability in cedar, oak, and walnut:
http://www.amazon.com/QUICK-CHANGE-COUNTERSINK-DRILL-SNAPPY/dp/B000XXZME8
http://www.homedepot.com/p/General-Tools-Plug-Cutter-Set-3-Piece-S31/202252123
Or you use a proper size countersink bit.
I have these, they work well
Yeah, I'd go with the Kreg stuff, since they really aren't a big difference in price. Kreg is made with woodworking in mind. It does make a difference. (And the square-drive screws are much less frustration-inducing than Phillips)
http://www.amazon.com/Kreg-DDS-3-Inch-Square-Systems/dp/B000BKBYWW
So is this a tap set specifically made for drilling then? I've only seen them with the T bars but an amazon search of 'drill tap set' brings up a few options.