I more or less know what I’m getting into this time; the structure will be built of 1/4-20 bolts and cross dowels, with a small smattering of larger bits (to hold on bearings and stuff), some angle aluminum, and a handful of washers and nuts.
I went through some thrashing last time around about whether I should buy hardware at the store or buy “the kit” from BuildYourCNC. Because I didn’t really know what I was getting into, and because I was otherwise going to be buying all the bolts at retail, and because I couldn’t find a cheap source of online cross-dowels, I decided to buy the kit, even though I felt it to be a bit overpriced at the time. Without a CNC machine (or drill press, or …) at the time to back me up, I felt that there were some parts in the kit that I would have problems dealing with on my own.
This time, it’s different. I mean, I ended up having to “top off” the kit at retail prices anyway, when I ran out of 1/4-20 bolts a couple times. And unlike the BRAs from the Book machine, there are really not that many parts in the new build that are “strange”.
Also, I found cheap cross-dowels online (amazon has them for 29.9 cents each).
So the hardware breaks out this way:
Roller chain and its components, plus the V-bearings, should be bought from Patrick.
nuts, bolts, cross-dowels should be bought in quantity online (I use 1/4-20 hardware all the time anyway).
aluminum angle, threaded rod, washers, and any “off-size” bolts can be bought at retail (I don’t foresee this being more than $100 in bits and bobs).
So, here’s a rough analysis of the price breakdown:
Patrick parts:
– Roller chain (#25, 2×12′, 1×5′ @ $2.40/ft) = $70
– drive sprockets (1/4″ bore, 9 tooth, 3 @ $11) = $33
– idler sprockets (5/16″ bore, with bearing and bolt, 5 @ $16) = $80
– 1/4″ to 1/4″ rigid coupling (2 @ $21 ) = $42
– 1/2″ collar (2 @ $8 ) = 16
– V-bearings (16-pack) = $128
Patrick subtotal: $370
If I decide to upgrade to ACME screw for Z, and spring for a couple of new bearings and a bracket for the screw, this adds $75 = $445)
Nuts, Bolts from Pointe Products:
– 15402-AV 1/4-20 x 1.5″ ( 200ea = 4bags @ $8.76 ) = $35
– 15404-AV 1/4-20 x 2″ ( 100ea = 2bags @ $11.08 ) = $22
– 10-10001 1/4-20 hex nut (100ea = 1bag @ $1.55 ) = 2
Pointe Products subtotal = $60
(they also sell 1/4-20 threaded rod in 3′ lengths for $1.70 per, I would need 2)
Angle Aluminum for the rails from Home Depot:
– 1 1/2″ angle aluminum, 8′ length ( 4 @ $18.50 ) = $75
Home Depot subtotal = $75
Total is $560. This compares to BYCNC’s price of $923 for the same set of stuff.
I am reusing the Z-motor coupler, which saves $10 or so. Ordering the rails from BYCNC would mean they are pre-drilled (I think). And his parts list as listed on the BF webpage only adds up to $850 if you use the prices he has there, and only adds up to $700 if you use the updated prices from elsewhere on the site (he’s found much better prices on roller chain and sprockets). So there is about $200 in markup over just buying the parts piecemeal from him (for his time and effort figuring out the parts list, I suppose), and a 60% markup over buying stuff a la carte and sourcing nuts and bolts myself.
The Book machine was about $200 in the hardware kit, and included bearings, couplings, and BRAs that I wasn’t going to be able to figure out on my own. This kit is 4x as much, but I can source the “easy to find” stuff on my own and save a bundle.
I think that I’m going to go it alone on this one, unless Patrick decides he can sell me the hardware kit at half price, too.