One step closer. Apparently adding extra nuts into the extrusion is easy from the bottom plate. I also found these nuts from China that fits both misumi and openbuilds extrusion. It’s also el cheapo. Perfect to complement the nuts I got from openbuilds.
Nice, you have a link?
Nice find! Must have link. 
$5.50 + $5 shipping for 50 pieces to US. If you buy multiple packs (why won’t you? If you are buying 1 pack, might as well buy it in your next openbuild order) it comes out cheaper than cheap.
@Dat_Chu Thanks!
@Dat_Chu Wow that fit. Thanks for sharing! I’m going to buy a few packs. Now to find post install t-nuts!
They have post install T nuts too but I haven’t tried.
Hey where did you get your spindle. I am trying to hunt down a good price.
@Dat_Chu I’ll bite on the post installs. How long did shipping take?
@Isaac_Arciaga Get your order in now because new years is coming up and EVERYTHING shuts down for a few days.
Shipping was rather quick but then I don’t remember since I am a slow-build mode. And yes, like John said, Chinese new year is coming, better order NOW.
Yep! trying to gather the last bits before China shuts down for a month! Thanks!
I’ve been using them a while. Much, much better than the useless OB ones that twist and fall out. Apart from the delrin ‘tyres’ and the actual extrusion and the low-profile bolts, haven’t been very impressed with OB parts quality -and they’re charging premium prices for things like washers and switches… Way over what they are actually worth.
There are also these in case someone is looking for the drop-in tnuts http://www.aliexpress.com/item/100PCS-M5-T-nut-Hammer-Head-Fasten-Nut-Connector-Nickel-Plated-for-20-series-Slot-Groove/1638209928.html
They are awful - take it from me. They might drop in, but they are too narrow - they spin around and are more likely to fall out again. That’s the same as the OB store sells - at 75c for six!!! WTF? If you do want that style, buy the ‘4040’ M5 hammer-head nuts. They will drop in, but you can make them stay in place.
The best drop-in nuts are the ones with a ball and spring, but the opening on the V-trak is just a little too wide and they often spring back out again - you need to put them just-so.
That is the reason for the issues surrounding the t-nuts - the mouth of the track gap is wider than normal 2020 track.
I have about 10 different types of t-nut and have now narrowed it to only using two types with V-trak. The wide ones you originally posted and these: 30 series roll-in with leaf spring: http://www.aliexpress.com/item/30-Series-Self-Aligning-Roll-In-T-Nut-with-Spring-Leaf-M5-6-8-Thread/32255233047.html
Awesome info @Mike_Thornbury . Thank you.
Any recommendations for l brackets and other joining plates and such for extrusion?
Other stuff I have found cheap/useful:
I have used a couple of different types of L-bracket…
These are small, but very strong: http://www.aliexpress.com/snapshot/6329820935.html?orderId=64483712574995
These are my preferred size, but need the locating nub grinding off if you want to use them against a flat surface - easy enough to do:
http://www.aliexpress.com/snapshot/6252325548.html?orderId=63890776544995
These aren’t as low as the OB nuts, but very good, stainless and the head is pretty low:
http://www.aliexpress.com/snapshot/6252325543.html?orderId=63890776534995
That’s just one size - you can get any size you want, pretty much.
I sleeve all my wires going through the gantry plates, etc. - this is great - more than enough room for 4x stepper wires and so cheap I bought multiple colours - 25ft/8M goes a loooong way.:
http://www.aliexpress.com/snapshot/6249259866.html?orderId=63863404154995
https://plus.google.com/u/0/photos?pid=6114059473007562082&oid=101708620681849403392
This is the same gauge as the stepper wires - so I assumed it would be fine for joining them to the controller - and so cheap.
http://www.aliexpress.com/snapshot/6249249283.html?orderId=63874633784995
10mm PET sleeving is great for bundling wires together. I always use heat-shrink on the cut ends to stop them fraying (it also keeps the wires in place):
http://www.aliexpress.com/snapshot/6332556064.html?orderId=64506271934995
HUGE bottom-clearing bit - 2" wide: http://www.aliexpress.com/snapshot/6406711892.html?orderId=65109439844995
I forgot the one absolutely game-changing part I use: http://www.aliexpress.com/item/100PCS-Stainless-Steel-304-M5-16-Hexagon-Socket-Head-Self-Tapping-Screw-Sound-screw-model-screw/1646507494.html
You can get black oxide as well as SS: http://www.aliexpress.com/item/100PCS-M5-16-Steel-with-black-Oxide-Hex-Socket-Cap-Head-Self-Tapping-Screw-model-screw/1942132296.html
Drill out the hole in the extrusion with a 4mm or 4.5mm drill (or the ancient equivalent), then just drive these home - I haven’t tapped a thread for years.
Typically I use M516 for non stressed joins, M525mm for gantry plates, etc.
I set up a production line with all my cut extrusion and drill it all in one go, then assembly is an absolute doddle. You MUST lubricate, though, or risk a head breaking off in the alloy. I always have the torque turned down on my Makita battery drill so they go in al the way home, then do the final torque by hand. The easiest way to lubricate, I’ve found, is to put all the screws in a small plastic container and spray them with silicone spray, WD40, or whatever (I prefer silicone), then just use them straight from the container. Silicone spray has that ‘dry’ feel, rather than the sticky fish-oil feel of WD40 and works just fine.
Sure, the screws cost a little more, but they are definitely worth the cost in time and hassle savings.
Wan Fang is the place I bought from - they charge for shipping!! But I tend to send them a big list of stuff and they fulfill everything at one time and their courier shipping rates are very reasonable. They have sent me stuff not on their listings - you just need to let them know (preferably with another link) exactly what you want. I ordered M3 washers and ended up with M5, even though the whole rest of my order was M3 - but it was my fault, I put M5 by mistake. Other vendors might have emailed to check, but they are a bit robot-like - make sure you check your work!
Shop around, there are lots of places if you want free shipping, but that takes 4-6 weeks here (I am still receiving November orders) So I tend to buy $200+ at one time. You are in the US - you can probably source a lot of that stuff locally.
@Mike_Thornbury Fantastic hardware alternatives! Thank you so much for posting those.