KRMx01
The KRMx01 Cost Log
When I built the last CNC machine, the JGRO Router, I wasn't too good about keeping track of costs. This time around I hope to do better. So, as I buy materials to build the machine, I will document the cost here. That being said, I plan to detail the actual items and amount. I apologize now if it is too verbose. :-)
| Item | Cost | Notes | ||||||||||||||||||||||||||||
| Books, Building the KRMx01 CNC and Upgrading and Operating the KRMx01 CNC | $79.88 | Ordered through Amazon.com $74.90 + $4.98 shipping. | ||||||||||||||||||||||||||||
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80/20 Aluminum extrusion. This precut kit contains: |
$323.81 | Ordered through Ebay link provided by Kronos Robotics. $283.65 + $40.16 Shipping. | ||||||||||||||||||||||||||||
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Fasteners (I ordered all the fasteners for the project, bolts, nuts, Washers, machine screws and the three 10' pieces of threaded rod.) All the hardware did not come in when I paid for the order. The rest of it will be on another ticket. I still have other hardware to buy, like bearings, shaft collars, machine bushings, etc.
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$196.11 | Bought through local Fastenal store. $178.69 + $17.42 in taxes. | ||||||||||||||||||||||||||||
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Angle Iron. All the angle needed for the project including the table. I bought all the angle in 20' sticks because it was more than $12 per cut. Quantity of each is in parenthesis. The extra angle can be put to use for something.(1) 2" x 2" x 1/4" *** After examination I received (2) 2" x 2" x 3/16" angle instead of (1) 1/4" and (1) 3/16". Other than losing a little rigidity but unlikely to affect the machine, I will use the 3/16" angle for the Y-Axis rather than going through the hassle of exchanging it. |
$195.00 | Valley Steel and Welding (a local company) | ||||||||||||||||||||||||||||
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Fasteners - I received the rest of the fasteners that were missing in the initial order from Fastenal. (2) 1/4"-20 x 10 feet threaded rod |
$36.15 | Bought through local Fastenal store. $32.29 + $3.86 in taxes. | ||||||||||||||||||||||||||||
| (6) Cans of Krylon Spray Paint - Cherry Red primer/paint combo, gloss. This is for the stand and the assorted pieces of steel in the project. | $32.53 | Bought from local Walmart Store. $29.64 + $2.89 in taxes. | ||||||||||||||||||||||||||||
| (40) 1/4"-20 oval nuts, Woodcraft® item number 147922 (10 pack) @ 3.99 ea. These are used for attaching the Y-Beams to the uprights. | $23.46 | Purchased from Woodcraft® website. $15.96 + $7.50 in shipping. | ||||||||||||||||||||||||||||
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(1) Sheet 3/4" x 49 x 97 MDF (First layer of CNC Table) $35.72 (1) Gallon Velspar Black Gloss Paint. (To paint wood parts) $30.97 (6) 4" foam rollers. $8.98 |
$83.05 | Bought from Lowes Store. $75.67 + $7.38 in sales tax. | ||||||||||||||||||||||||||||
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(4) Cans of Krylon Spray Paint - Cherry Red primer/paint combo, gloss. This is for the angle pieces used throughout the machine |
$21.69 | Bought from local Walmart Store. $19.76 + $1.93 in taxes. | ||||||||||||||||||||||||||||
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(3) 1-5/8" Struts. These are the U channel struts that get bolted to the table top in which the X-Axis rails get bolted to. |
$61.54 | Bought from Local Lowes store. $56.07 + $5.47 in sales tax. | ||||||||||||||||||||||||||||
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(4) 0.75 x 0.75 x 0.125 - 6 feet long 6063-T52 Aluminum Angle. |
$55.98 | Bought from OnlineMetals.com. $28.52 for metal + $3.00 cut fee + $24.46 shipping. | ||||||||||||||||||||||||||||
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(24) RM2ZZ 3/8" V-Groove bearings. These are for the carriages. (Please note you only need 16 for the project, but I found mine on Ebay in packs of 8. I wanted a few extra just because you never know! These bearings cost $5.35 each, a significant savings of the $11.00 that VXB wants on their site.) |
$128.40 | Ordered from ebay. (3) packages of 8 bearings at $42.80 per pack. | ||||||||||||||||||||||||||||
| (4) Cans of Krylon Spray Paint - Cherry Red primer/paint combo, gloss. This is for the angle and other steel pieces used throughout the machine. (up to 14 cans now. Hindsight being what it is, it may have been better to buy a quart of paint at the automotive paint store and sprayed it with my compressor and gun!) | $21.69 | Bought from local Walmart Store. $19.76 + $1.93 in taxes. | ||||||||||||||||||||||||||||
| (1) Nema 24 Stepping Motor - 425 oz-in (1) Stepping motor driver - 24-40 volts DC, up to 3.0 amps, microstepping from 1 to 1/64 (6) roller arm limit switches. These were purchased from buildyourcnc.com. I only ordered 1 stepper and driver because I already have 3 of these from a purchase when I updated my JGRO machine. I intend to reuse those motors, controllers, power supply and breakout board. |
$150.18 | $49.00 for Stepping motor. $54.95 for driver $30.00 for Switches $16.23 for shipping |
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(8) DumpsterCNC Acme 1/2"-10, 5 Start Nuts Part number CRP161-00-02 These were purchased from CNCRouterParts.com. The original nut has been replaced by the part number above. The original nut was all plastic where this on is in an aluminum housing and should, I guess, be a little more durable. All I really noticed was buying 8 of them was a bit pricey!!! |
$372.10 |
$279.60 for Acme nuts ($34.95 ea) |
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(3) Wide-Rim Zinc-Plated Steel shim, .075" thick, 1/2" ID, 7/8" OD, packs of 25 Ordered from McMaster-Carr. |
$388.39 | $9.78 for Shims ($3.26 ea) $28.42 for collars ($2.03 ea) $199.50 for 6' rod ($66.50 ea) $33.25 for 3" rod $94.43 for bearings ($13.49 ea) $23.01 Shipping |
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(1) Aluminum 6061-T651 Bare Plate 1/2" thick cut to 5" x 8.875" Purchased from onlinemetals.com. This was a custom cut order, and was not charged a cut fee for whatever reason. |
$26.03 | $19.08 for plate $6.95 for Shipping |
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(26) 1/4"-20 x 7/8 long coupling nuts Purchased from local Fastenal |
$12.63 |
$11.51 for nuts (.44 ea) |
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(1) Hitachi Router Mount (RM-Hitachi) from K2CNC |
$82.40 |
$69.95 for Router mount and $12.45 shipping. |
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(1) Sheet 4' x 8' x 3/4" MDF. Bought this at Lowes and will be used for the table top that sits on the struts. |
$37.22 |
$33.91 for MDF |
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(4) Cans Rust-o-lium Black gloss spray paint I bought this to paint the top layer of the table. I messed up and left the gallon of paint I was using for this in my building which is unheated. Needless to say, it ruined. |
$24.83 |
$22.62 for paint |
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(2) Cans of Krylon Spray Paint - Cherry Red primer/paint combo, gloss. |
$10.84 |
Purchased at local Walmart |
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(4) 3/8-16 x 2" bolts from local Fastenal |
$2.41 |
$2.20 for bolts |
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(100) 1/4" split wahers |
$8.19 |
$7.46 for hardware |
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(2) 1/4-20 x 3" full thread from local fastenal |
$0.58 |
$0.53 for bolts |
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(70) 1/4-20 x 3/4" carriage bolts |
$7.13 |
$6.50 for hardware |
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(1) 1/8 x 2" x 36" hot rolledf steel from local D&C Auto Parts |
$7.67 |
$6.99 for steel |
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(2) 3/8" washers 25 pack |
$28.33 |
$25.93 for hardware |
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(6) push in connectors (for 14AWG wire) |
$7.45 |
$6.79 in materials |
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(5) 2 pin male chassis mount mic connector (GL-A286C) |
$45.75 |
$39.90 for connectors |
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(4) CBC4M 4 pin mic connector |
$38.95 |
$32.00 for connectors |
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(1) S-350-36 Power supply 36vdc 9.7a |
$34.20 |
$34.20 for supply |
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(1) S-100-5 Power supply 5vdc 20a |
$18.99 |
$18.99 for supply |
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(2) Fans, 5 VDC, 16.6 CFM, 60mm x 60mm x 15mm |
$14.70 |
$11.90 for fans |
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(1) Air exchanger for Hitachi router |
$103.92 |
$92.95 for Air Exchanger |
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(1) SuperPID for Hitachi router and computer control |
$172.75 |
$155.00 for SuperPID |
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(1) Touch Plate |
$119.39 |
$89.75 for Z Touch Plate |
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(2) Solid State Relay boards |
$35.54 |
$14.00 ea. for SS Relay Boards |
Total cost: $3009.86
The Kronos Robotics KRMx01 CNC
I have been using my old JGRO CNC machine for a while now and while I like the machine, it is time to take a look at improving and moving on to something better. Most of the issues I have with the JGRO machine is its lack of rigidity. I can cut but have to take things slow or I get enough flex that the part will be out of tolerance. With that problem in mind I set out to find a new machine. Now there are loads of plans for CNC machines on the Internet, some free and some that cost money. I knew that I wanted to move away from a wood machine to something made from metal. In the research that I have done, this led me to two choices that I was considering. That would be the MechMate and the Kronos Robotics KRMx01 or KRMx02. I wanted a machine that I could build that was within my skill set. This sort of left out the Mechmate for me because I have very little experience with fabricating metal to the level that is required for that machine. That left me trying to decide between the two models that Kronos Robotics have to offer.
KRMx01 or the KRMx02?
Both machine options from Kronos are pretty good. The KRMx01 machine is a screw driven machine giving a good range of precision but at a slight sacrifice of speed and some other components that will need occasional adjustments through use and normal wear. For example, the nuts used to drive the machine are plastic and will wear and will need some occasional adjustment to compensate. The KRMx02 is a very rigid machine designed for speed by using a rack and pinion system but at a loss of precision. It was a tough decision for me to decide which machine to build. In the end after having conversations with the designer, Michael Simpson, I selected the KRMx01 model for the precision with the option of making a couple of upgrades to the machine to make it better.
Making a good thing better.
Discussions with Michael of Kronos Robotics led me to a solution that at lease at this point in time fits my needs very nice. The long term plan for my KRMx01 build will be to replace the Aluminum angle used for the bearing rails with ones made from hardened steel, and finally use the Z-Axis from the KRMx02 to provide more router support than the KRMx01 would give. Probably the best solution of all would have been to build the KRMx02 with leadscrews instead of rack and pinion. The gained speed of the rack and pinion does is less important than the precision of the leadscrew. Beside talking with Michael, I bought his books on both machines. Even if you are still in the research phase of your planning, these books are worth having in your library. The KRMx01 book can be had as a free PDF download from the Kronos Robotics website, but buying a printed copy from Amazon with illustrations your can read is worth the few extra bucks. I have images of all three books below and you can click on them to get a better view of them. If you are interested in these books, take a gander at kronosrobotics.com and check them out.
I hope you enjoy the journey!