I was really bummed that doorway pull up bars are sold out everywhere due to Covid-19 / quarantine, so I decided to make my own. It uses $20 of materials to make which is on par with similar bars on Amazon.

Doorway pull up bars use leverage around the door to hold it up, so it doesn't require any screws or modifications to your door and the weight is spread out around the door.

Disclaimer: I don't know how strong it is, and the weakest point is definitely the set screw coupling the two pieces together. I take no responsibility for the safety of this, by building a copy of it yourself you are accepting the risks.

Update: I added a reinforcer part that holds a 3/8" metal rod on the inside of the conduit from the 90° angle piece to the front grips, so that all the forces aren't reliant on the set screw connector working. This piece should be 3D printed in any standard filament (PLA/PETG/ABS), I printed it with 7 perimeters, 5 layers on the top and bottom, and 30% infill. The printed parts are strong enough that they probably don't need the metal rod in the middle as well but it's there if you want it. The Fusion 360 file uses parameters for the rod diameter so you should easily be able to use a steel rod of a different size.

Update 2: After about a week of using it, one of the set screws came loose and the rod started sliding out. Luckily the 3D printed piece caught it so I didn't fall, but it was still concerning. So Tighten the set screw!! Really well. Maybe even screw into the zinc coupling somewhere else and add a screw/bolt so that it physically can't slide. If you notice your bar getting less and less parallel to the frame, stop and check all the set screws.

Step 1: Required Materials

Materials

1" EMT Conduit - You only need around 60" of it (5 feet), but Lowes only sells it in 10ft sections. $11 - Lowes
2 of Right Angle Elbow (1" EMT). $6.18 each, $12.36 total - Lowes
2 of Set Screw Coupling (for 1" EMT). $0.87 each, $1.74 total - Lowes
2ft long 2x4 - $0.50 ish? You could also use more EMT for this I guess
3" long bolts and nuts - 2 each. I used 1/4-20 x 3 in machine bolts here
2.5" wood screws - 2 of them
(Optional) washers to go between the bolts and EMT
(Optional) Something for covering the ends of the EMT on the doorframe, like duct tape or foam or literally just a rag taped to it. I used 3D printed Ninjaflex to make my own cap but I understand 99.9% of people don't have that.
(Optional but recommended) 3D printer and filament for the center rod reinforcer. Alternately, just shove a rod of any size in there and duct tape it in place.

Tools

Something to cut 1" EMT - I used a jigsaw, you could also use a metal hacksaw.
Drill and drill bits
- Optional - Step Drill bits make it really easy to cut large holes in the metal.
Clamps to hold the EMT while cutting/drilling it

Time: ~2 hours if you're doing it in your apartment clamping to the kitchen counter and figuring it all out as you go. Probably 30 minutes if you're following this tutorial and have a real shop and a drill press.

Max weight: Not sure. I welcome any suggestions for making it stronger

Step 2: Step 3: Cut Lengths

Cut the EMT Conduit to the following sections:

42" (or approximately 2" more on each side of the molding of the doorframe.)
8.5"
8.5"

Cut the 2x4 to somewhere between 2 and 3 feet long, you really only need 3" longer than the spacing of the handles, and with my handles spaced 18" apart (next step) 24" is plenty for me.

If you're using the center rod reinforcer then cut it to approximately 10" long.

Step 3: Step 3: Drilling Holes and Assembly

First you need to decide how far apart you want the straight grips to be. I estimated that 18" apart felt about right, but anywhere from 16" to 19" is probably fine. I'm 6"2 so I wanted them a little bit wider than a shorter person might want them. Let's do it for 18"

Here's the order that I drilled things in:

Right Angle Connectors to 2x4

Measure 18" apart on your 2x4 and mark the hole locations. You want two wood screws for each side, so make sure the right angle elbow is far enough up on the wood for that. Maybe don't put it all the way up though because you want space for your hands
Clamp one of the right angle bars onto the wood on top of your marked holes as shown in the picture
Drill holes into the wood. First use a 11/64" drill bit in the EMT so the screw can pass through it without issue, then use a 1/8" bit in the 2x4 wood so that the wood screw gets a good grip.
Drill in the first screw.
Tilt the EMT until it's as close to 90° to the wood, then drill/screw in the second screw. Repeat for the second right angle connector

Set Screw Couplers

Screw in the set screw connectors wherever you want, I angled them at 45° because I thought it looked cool and just in case I needed to screw into them (Didn't need to). Attach the 8.5" sections of EMT to each set screw

If you wanted to make this part more secure, use some bolts and nuts for this part as well. I didn't feel like buying more bolts so I didn't.

Horizontal bar - the main stuff

Hold up the assembly so far to your doorway and determine where the long conduit section needs to be attached. For my doorway with molding on both sides it needed to be right up against the set screw coupler, so I marked the spots there
Clamp and drill holes through the horizontal pipe and the right angle connector where it needs to be. I just used a single bolt to connect these, but it's a big bolt so I used a step drill bit to drill it to the right size. This part will depend on your setup, but use lots of clamps and hope for the best with alignment. If your holes aren't lined up perfectly don't worry about it, just drill the hole a little bigger. EMT is plenty strong.
Drill the first hole, put a bolt through it, then mark where the second bolt hole needs to be on the two pipes. For alignment it might be easiest to drill a small hole through the two pipes while they're sitting on top of each other so it's perfectly aligned.
Note - if you're using the center rod reinforcer, you'll slide it in before putting the bolts in but after drilling all the holes.

Step 4: Finishing Touches / 3D Printed Pieces

You'll probably want something on the sides of the EMT conduit where it presses against the doorframe. You can use duct tape an a cloth or an old shirt, or just a bunch of duct tape, whatever you want. I was feeling fancy so I used a flexible filament (Ninjatek Ninjaflex) and 3d printed some end caps with padding for the doorframe area. I also printed some small caps for the end of the hammer grips. The STL files are above, along with the Fusion 360 file I used for making them if you want to modify them yourself.

I also added 3M Painters Tape to the wood part just to make sure it doesn't scuff up the area above the door frame.

I used sandpaper to clean the conduit, I used 320 grit to clean off the outer layer and then 600 grit to smooth it. You can spray paint the rods if you want a nicer finish.