# Robotics, stepper motors and CNC hobbyists (and professionals) - please comment on my plan... **URL:** \ **Category:** In My Humble Opinion\ **Created:** [December 30, 2016, 10:29am UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895 "2016-12-30T10:29:58Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 3, 2017, 8:43am UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/21 "2017-01-03T08:43:47Z")
> [@Projammer](#): > > I keep seeing the [DIY Smart Saw](http://www.diysmartsaw.com/fb/?tid=main_med_fbk_diysmartsaw) advertised on fb and other sites. The site claims it can be built for $160 if you have access to scavenged and used parts or $500 if you go with new parts. > > I know a lot of stuff that’s advertised on fb is of the X10 camera caliber, but I can’t see any obvious scaminess to this one. I don’t think it’s so much a scam as money-for-old-rope - it looks to be a repackaging of the open-source builds you can find all over the internet already (although it’s hard to say, because the promo video is so glossy and superficial). I looked at some reviews of this video tutorial/documents and it does look like some effort has been put into the production, but really, I don’t think there’s anything in there that you couldn’t find for yourself on instructables, youtube and various maker blogs. ---
**Author:** ![Projammer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/projammer/32/559_2.png) [@Projammer](https://boards.straightdope.com/u/Projammer)\ **Post date:** [January 3, 2017, 10:26pm UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/22 "2017-01-03T22:26:36Z")
So you’re paying $39 to have someone else do the research for you. Not too bad of a deal. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [January 3, 2017, 10:33pm UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/23 "2017-01-03T22:33:30Z")
> [@Mangetout](#): > > I think I’m going to chew on the idea for a while. I know I have the tools and skill to make my own device, and my eagerness to have one to use is clouding my judgement. Time to cool off. > > Of course, I can spend the interim thinking about how I would build it if and when I do build it - so here’s my outline plan: > > Static bed, moving XY gantry, with mounted Z axis. > > Build the Z axis first, then build an X axis gantry on a Y axis carriage that’s capable of accommodating it - so many projects I’ve seen seem to finish with the Z axis, but it seems sensible to start with that - as any unforeseen problems with size etc can be engineered around in the rest of the build. > > I could use metric stainless threaded rod for the leadscrews - M10 probably. I can easily make anti-backlash nuts using two M10 nuts, some small pieces of ply, a spring and some small containing bolts. The pitch of metric threads is quite shallow, so this means the leadscrews could be driven directly by the motors without compromising resolution. > > The runners/rails are probably the biggest unknown. I can manufacture HDPE wheels that would run in channels or on rails with quite low friction, or I could make or buy bearings that run directly on cylindrical rods. Not sure about this one. Rods are the way to go. There’s no way that wheels in channels will be free of play (unless you use pairs to grab a rod, in which case you might as well use a plastic slider on a rod). But, you can buy low-play linear bearings really [cheaply](http://www.ebay.com/itm/2pcs-8mm-Bearing-Bushing-LM8LUU-Linear-Motion-RepRap-3D-printer-/231194907514?hash=item35d44a537a:g:GssAAOxyQfJTgTrf). Why would you want to make such a critical part yourself? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 4, 2017, 11:00am UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/24 "2017-01-04T11:00:24Z")
Yeah, the only concern I have with rods is potential sagging in the middle of the longest horizontal axis - channels can be very resiliently supported. Rails can be supported in a way that doesn’t interfere with pinch-wheel pairs running on them. Rods just need to be engineered thick enough that they won’t significantly bend in the middle under the weight of the gantry, motors and spindle. Assuming a 1 metre Y axis supporting a gantry that is, say 25cm broad at the base (so maybe 70cm of Y axis travel), how thick would you make the rods? ---
**Author:** ![N9IWP](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/n9iwp/32/3154_2.png) [@N9IWP](https://boards.straightdope.com/u/N9IWP)\ **Post date:** [January 4, 2017, 11:52am UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/25 "2017-01-04T11:52:46Z")
Here an interesting kickstarter – it doesn’t use rails at all: [https://www.kickstarter.com/projects/1830738289/maslow-cnc-a-500-open-source-4-by-8-foot-cnc-machi?ref=category\_newest](https://www.kickstarter.com/projects/1830738289/maslow-cnc-a-500-open-source-4-by-8-foot-cnc-machi?ref=category_newest) Brian ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 4, 2017, 12:13pm UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/26 "2017-01-04T12:13:40Z")
> [@N9IWP](#): > > Here an interesting kickstarter – it doesn’t use rails at all: > [https://www.kickstarter.com/projects/1830738289/maslow-cnc-a-500-open-source-4-by-8-foot-cnc-machi?ref=category\_newest](https://www.kickstarter.com/projects/1830738289/maslow-cnc-a-500-open-source-4-by-8-foot-cnc-machi?ref=category_newest) > > Brian Yeah, I spotted that one in my searches - really interesting, but the project appears to have gone full circle through funding to rollout and now the product itself is no longer available. They cite a surprising level of accuracy for this machine (0.4mm IIRC), which I found a bit hard to believe, given that the cords supporting the thing _must_ have some elasticity to them. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [January 4, 2017, 5:17pm UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/27 "2017-01-04T17:17:57Z")
> [@Mangetout](#): > > Yeah, the only concern I have with rods is potential sagging in the middle of the longest horizontal axis - channels can be very resiliently supported. Rails can be supported in a way that doesn’t interfere with pinch-wheel pairs running on them. Rods just need to be engineered thick enough that they won’t significantly bend in the middle under the weight of the gantry, motors and spindle. > > Assuming a 1 metre Y axis supporting a gantry that is, say 25cm broad at the base (so maybe 70cm of Y axis travel), how thick would you make the rods? If you are worried about sagging, you can get supported rods, with split bearings. Here’s a reasonably priced set, including ball screws: [http://www.ebay.com/itm/ballscrew-RM1605-300-900-1150mm-3set-SBR16-linear-slide-rail-BK-BF12-bearing-CNC/151202905765](http://www.ebay.com/itm/ballscrew-RM1605-300-900-1150mm-3set-SBR16-linear-slide-rail-BK-BF12-bearing-CNC/151202905765) ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 4, 2017, 7:30pm UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/28 "2017-01-04T19:30:25Z")
That’s reasonably priced for what they are (and they would be perfect), but way out of range for my project. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 12, 2017, 3:59pm UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/29 "2017-01-12T15:59:54Z")
Well, I just took the plunge - I actually just ordered one of [these](https://www.amazon.co.uk/d/Power-Milling-Machines/Sanven-3040T-Dq-Upgrade-Engraver-Engraving-Milling-Drilling/B00DGLT4NO/ref=sr_1_1?ie=UTF8&qid=1484236253&sr=8-1&keywords=3040t-dq) - because that’s a very good price. It’ll need an old PC with a parallel port to run it, but I’m treating this as entry-level - my cunning plan is: [ul] [li]Treat this as a very definitely ‘entry level’ device[/li][li]Use it to acquire the necessary skills to run the thing[/li][li]Study the design and its good/bad parts[/li]li build my own larger device at a later date - perhaps by cannibalising this unit and rebuilding it on longer tracks etc, and/or using this unit to manufacture some of the parts.[/li][/ul] ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [January 12, 2017, 9:41pm UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/30 "2017-01-12T21:41:31Z")
> [@Mangetout](#): > > It’ll need an old PC with a parallel port to run it, … You know you can get USB-Parallel cables for real cheap, don’t you? ---
**Author:** ![buckgully](https://avatars.discourse-cdn.com/v4/letter/b/eb9ed0/32.png) [@buckgully](https://boards.straightdope.com/u/buckgully)\ **Post date:** [January 12, 2017, 11:57pm UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/31 "2017-01-12T23:57:18Z")
> [@ftg](#): > > You know you can get USB-Parallel cables for real cheap, don’t you? USB-\>Parallel cables don’t usually work for these type of things. Most of the parallel port based CNC controllers are going directly to the hardware and bit-banging the pins to set stepper direction and trigger the steps. It’s very important for the timing to be accurate, and USB-Parallel converters mess that up. Also, the CNC hardware usually expects 5 volt TTL where as the USB cables (and some bulit in laptop parallel ports) are 3v. I have plans from a couple of different sources, and have built a HobbyCNC controller board, but I have yet to actually build out a whole CNC system. It’s kind of overwhelming, and I’m afraid of wasting time and money on things that turn out to not work at all. At this point I’m very tempted to get something like an Xcarve because my time is worth more to me than the price difference. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [January 13, 2017, 12:10am UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/32 "2017-01-13T00:10:26Z")
I’m late to the party, naturally, but you can get parallel port cards that plug into PCI Express slots. Startech do one [here](https://www.startech.com/uk/Cards-Adapters/Parallel/1-Port-EPP-ECP-PCI-Express-Parallel-Card-~PEX1P). ---
**Author:** ![drachillix](https://avatars.discourse-cdn.com/v4/letter/d/48db29/32.png) [@drachillix](https://boards.straightdope.com/u/drachillix)\ **Post date:** [January 13, 2017, 3:19am UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/33 "2017-01-13T03:19:20Z")
> [@Typo\_Knig](#): > > That’s not as much protection as you hope. If bad guys start targeting CNCs, or their data files, or the cloud-based CAD/CAM/CAE software, builders could be in a bad way. the I’ll have to think on suggestions for improvements. For a hobbyyist user with a dedicated machine who uses the machine only for CNC tasks and accessing a handful of CNC related sites like thingiverse, your concerns are approaching tinfoil hattery. Machines with limited if any browsing very rarely have problems. We have about a dozen internet connected machines driving various CNC/3d printer/laser cutters. Never been a meaningful problem ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 13, 2017, 7:50am UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/34 "2017-01-13T07:50:04Z")
> [@buckgully](#): > > USB-\>Parallel cables don’t usually work for these type of things. Yeah, many of the parallel port controllers I have seen on sale explicitly state that they need a computer with a native parallel port, and not a laptop. > [@](#): > > Most of the parallel port based CNC controllers are going directly to the hardware and bit-banging the pins to set stepper direction and trigger the steps. Here’s where I’m confused though - they specify parallel port and Windows XP, but XP has the Hardware Abstraction Layer - I thought direct hardware access like that went away with Windows 98. ---
**Author:** ![Typo\_Knig](https://avatars.discourse-cdn.com/v4/letter/t/cdc98d/32.png) [@Typo\_Knig](https://boards.straightdope.com/u/Typo_Knig)\ **Post date:** [January 13, 2017, 8:43pm UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/35 "2017-01-13T20:43:23Z")
> [@drachillix](#): > > For a hobbyyist user with a dedicated machine who uses the machine only for CNC tasks and accessing a handful of CNC related sites like thingiverse, your concerns are approaching tinfoil hattery. Machines with limited if any browsing very rarely have problems. We have about a dozen internet connected machines driving various CNC/3d printer/laser cutters. Never been a meaningful problem If you transition from being a home hobbyist to being a paid business you’ll want to be more careful. Some bad guy takes your machine down when you’re a business, it’s your bottom line that suffers. Another concern is your networked machine being made part of a botnet - unless you’re monitoring your network traffic you might never know. My point is risks are there, and must be approached as thoughtfully as any other engineering decision. I’ll need to write up a more detailed approach in my copious free time. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 13, 2017, 9:09pm UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/36 "2017-01-13T21:09:59Z")
> [@Typo\_Knig](#): > > If you transition from being a home hobbyist to being a paid business you’ll want to be more careful. Some bad guy takes your machine down when you’re a business, it’s your bottom line that suffers. Another concern is your networked machine being made part of a botnet - unless you’re monitoring your network traffic you might never know. How will monitoring your network traffic help you to detect nonexistent attacks on machines that are set up as standalone, off your network? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 15, 2017, 4:57pm UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/37 "2017-01-15T16:57:16Z")
Huh. The Amazon seller cancelled the transaction at the last minute. I thought that price was a little too good to be true. Back to square 1. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 20, 2017, 7:18am UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/38 "2017-01-20T07:18:40Z")
> [@Mangetout](#): > > Huh. The Amazon seller cancelled the transaction at the last minute. I thought that price was a little too good to be true. Back to square 1. Turns out it was a scam. The first time I’ve actually encountered one on Amazon. The machines are back up and listed now, at bargain prices, but they are all marketplace items, and they all have a comment somewhere in the ‘condition’ notes saying that buyers should contact [some email address that has been munged to avoid detection by Amazon’s system] before buying. I emailed the address, out of curiosity, and got this response: > [@](#): > > Good Evening, > Firstly we apologize for delay but we had some problems with our server. > This product it is still available - Sanven Cnc 3040T-Dq Router Upgrade > From Cnc 3040 3040T Router Ball Screw Engraver Engraving 3-Axis Milling > Drilling Cutting Machine - ( It is a Special Price because we have a > stock liquidation ).The product it is New, original box - sealed, never > used and comes with 2 Years of warranty and all manufacturer supplied > accessories. > > The total price is £413.00 + £9.00 for shipping (1 - 3 business days). > > If you want to buy this product , please confirm your full name, > delivery address and your phone # to place your order at Amazon. We will > reserve the product for you and you will receive the order confirmation > from Amazon, the Amazon order contain all details about the next steps > to complete your purchase. > > Return policy is full money back or replace the product, you can return > it for any reason at all within 30 days. > Thanks for your time ! Scam. They will generate a fake Amazon invoice and take payment through some method that is not Amazon, then disappear with the money. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [January 20, 2017, 5:44pm UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/39 "2017-01-20T17:44:45Z")
> [@Mangetout](#): > > Yeah, many of the parallel port controllers I have seen on sale explicitly state that they need a computer with a native parallel port, and not a laptop. > > Here’s where I’m confused though - they specify parallel port and Windows XP, but XP has the Hardware Abstraction Layer - I thought direct hardware access like that went away with Windows 98. What goes from software bit twiddling through the OS HAL to a physical parallel port is close enough to work. What goes from software bit twiddling through a virtual parallel interface to a USB interface to the USB HAL to a physical USB to a cable with an embedded microcontroller that tries to generate a parallel signal from the USB data feed, all while costing less than 2 cents apiece with fine Chinese driver software, well … not so much. ---
**Author:** ![Paintcharge](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/paintcharge/32/7946_2.png) [@Paintcharge](https://boards.straightdope.com/u/Paintcharge)\ **Post date:** [January 31, 2017, 6:39pm UTC](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895/40 "2017-01-31T18:39:58Z")
Sorry to revive an older thread, but wanted to hear how things are going. I’m getting almost ready to make this jump too. I’m sure I can make the base, x/y/z axis parts, it’s the motors and software that are intimidating. Planning on using Maytec aluminum extrusion with [slides](http://maytec.partcommunity.com/3d-cad-models/eco-slide-maytec/?info=maytec%2Fmaytec_3d%2Fanbauzubehoer%2Feco_slide) as the primary x-axis bearing, with an acme screw to drive it. Using that extrusion because we build museum exhibits and have used quite a bit in the past, and there might be enough kicking around in the shop as scrap. Anyone else watched [Frank Makes](http://www.solidsmack.com/fabrication/frank-howarth-show-us-how-to-build-a-cnc/) a cnc? Helpful, but I know how to do what he shows there. And now 20 minutes later, after getting lost in youtube videos… [Previous page](https://boards.straightdope.com/t/robotics-stepper-motors-and-cnc-hobbyists-and-professionals-please-comment-on-my-plan/775895.md?page=1)