#linuxcnc Logs

Oct 15 2021

#linuxcnc Calendar

12:28 AM XXCoder: lol what
12:36 AM XXCoder: some person walked to front door and stole a small pot
12:36 AM XXCoder: didnt even steal all of 3 pots set
01:38 AM randy: morning
01:49 AM enleth: so I have this large plastic jug that used to contain gear oil and I need to store hydraulic oil in it while I modify the powerpack - what would be the best way of cleaning out the traces of gear oil?
01:51 AM enleth: engine cleaning detergent? dish soap? dishwasher detergent?
02:06 AM Deejay: moin
02:10 AM -!- #linuxcnc mode set to +v by ChanServ
04:18 AM solarwind: https://weldingmaterialsales.com/catalog/rbcuzn-c-low-fuming-bronze-bare-and-flux-coated/ why are these called bronze when they're made of copper and zinc (brass)?
04:42 AM JT-Cave: morning
06:02 AM CloudEvil: solarwind: The power of lies.
07:39 AM Tom_L: morning
08:11 AM Tom_L: enleth, dawn dish soap is known for being a good degreaser
08:11 AM Tom_L: thick film: naptha then dawn
08:11 AM enleth: Tom_L: I'll probably try dishwasher detergent, it's highly alkaline and concentrated
10:34 AM roycroft: jt-shop: are you about perchance?
10:51 AM JT-Shop: for a couple of minutes
11:02 AM JT-Shop: lunch time see you down in the Beer Cave
11:15 AM roycroft: it's ok
11:16 AM JT-Cave: I'm here
11:16 AM roycroft: i was going to ask if it's possible to add a feature to the part you're making for me, but if i need it i can add it myself
11:16 AM JT-Cave: so long as it doesn't need to be bigger lol
11:16 AM roycroft: of course not
11:16 AM roycroft: i just want the motor mount bolt holes to be countersunk
11:17 AM JT-Cave: I'm just fixing to generate the g code so send me the dxf
11:17 AM roycroft: that would require another setup though
11:17 AM roycroft: unless you reverse it and machine from the underside
11:17 AM roycroft: if you've not made it yet i guess that could happen
11:18 AM roycroft: but i can do it on a drill press
11:19 AM JT-Cave: yeah I usually do that on a drill press with a zero flute
11:19 AM JT-Cave: that's pretty thin for a flat head screw...
11:20 AM roycroft: i have an 82 degree countersink with a pilot, so i'll just do it here if i need to
11:21 AM roycroft: 1/4" should be fine
11:21 AM JT-Cave: I just checked starlink and it's supposed to be in this area sometime this year...
11:21 AM roycroft: head height on a standard 5/16" flat head bolt is 0.198"
11:21 AM JT-Cave: what about a button head socket screw?
11:21 AM JT-Cave: but it
11:22 AM JT-Cave: it's $99 a month...
11:22 AM roycroft: button head may work
11:22 AM roycroft: although flush would be better, since the bolts are so close to the edge
11:23 AM roycroft: i just want to be able to mount something underneath the motor - a power switch or possibly the vfd
11:23 AM roycroft: i could get low profile flat head screws that would have an even smaller head height
11:25 AM roycroft: or maybe not - undercut screws are not available in the length i need
11:26 AM JT-Cave: could you tap the plate and use studs?
11:26 AM roycroft: anyway, i used 5/16" flat head countersunk screws in 1/4" plate for my compressor motor, and that's held up for over a decade with no problem
11:26 AM roycroft: no
11:26 AM roycroft: the motor is flange mount - it will be perpendicular to the mounting plate
11:26 AM JT-Cave: ah
11:27 AM roycroft: so i'll need to use bolts from the underside that go through some standoffs to mount it
11:28 AM roycroft: the hole in the center of the bolt circle is just so i can replace the belt without removing the motor
12:07 PM JT-Shop: hopefully I did my ciphering correct and the fixture holes are in the correct spot
12:08 PM Tom_L: jt do you have any of those 'protection' daughter boards?
12:08 PM Tom_L: ribbon type
12:08 PM Tom_L: 50?pin
12:08 PM Tom_L: i'm lacking ONE output from getting A axis on the current daughter card
12:08 PM Tom_L: but i've got 2 more ports
12:09 PM Tom_L: with no place to mount another daughter card :)
12:10 PM JT-Shop: a 7i31?
12:11 PM Tom_L: i'm not sure, i haven't seen that one yet
12:12 PM Tom_L: i'm gonna look over the bit file and see if there's anything i can do
12:12 PM roycroft: or you can use the gpio pins on your rpi - and jt just wrote a hal configuration tool for that :)
12:13 PM Tom_L: i have one opto i'm not using for relays i might be able to use
12:13 PM Tom_L: i'm not using a rpi on this
12:15 PM Tom_L: my bit file and my pdf wiring chart aren't quite in alignment, i need to figure out what's going on there
12:15 PM Tom_L: i think it was a 7i37
12:15 PM Tom_L: unless there's one with just protection diodes etc
12:16 PM Tom_L: 7i37 might be overkill for this
12:17 PM JT-Shop: just looked at the 7i31 and it's pass through
12:17 PM Tom_L: looks more like a diagnostic board
12:17 PM Tom_L: with passthru
12:17 PM Tom_L: did he put buffers on that?
12:18 PM JT-Shop: a 7i37ta is a normal card
12:18 PM Tom_L: yeah
12:18 PM JT-Shop: I didn't see and buffers between the to plugs
12:19 PM Tom_L: no description or manual for it
12:20 PM Tom_L: i'll see what i can figure out in the next few days
12:20 PM Tom_L: surely i can find ONE io :)
12:21 PM Tom_L: i have a spare 7i47 i could use but that's way overkill for this
12:39 PM JT-Shop: damn I have to move the part a bit one of the fixture holes is half in another hole
12:53 PM * Tom_L declares the weekend official
01:00 PM * JT-Shop still has the 308 running...
01:00 PM JT-Shop: and almost broke my end mill by having too low rapid clearance
01:01 PM Tom_L: woops
01:16 PM JT-Shop: several rapid paths were right over the fixture screws which stick out about 1/4" and the rapid z was 0.200
01:17 PM Tom_L: is that set on the tool or the drawing?
01:17 PM Tom_L: mine is set per tool
01:18 PM captain_morgan: eeek, I hit a screw and destroyed (a thankfully cheap) v-bit last week
01:19 PM JT-Shop: set in CAM
01:19 PM captain_morgan: top of my 'get at the hardware store' list... brass screws. *sigh* been on that list for at least 2 months
01:40 PM JT-Shop: watching it cut the hole out and it looked like it was going to not need my intervention to remove the center until the last second the center went nuts and broke my carbide end mill :(
01:45 PM roycroft: i hope it's not my part that you're making right now
01:45 PM roycroft: it's certainly not important enough to be worth breaking end mills over
02:12 PM JT-Shop: it's my fault, I usually can catch it just before it breaks free and stop the VMC and remove it... just a second too late on the button
02:14 PM JT-Shop: it's only a $21 carbide end mill lol
02:52 PM Tom_L: it's easier to interpolate the whole center out
02:53 PM Tom_L: cheaper too :)
02:54 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/cnc/rotary/mount/Rotary_mount_path.jpg
02:54 PM Tom_L: i could have done that there too but experience told me not to
03:18 PM roycroft: so for this mill drivetrain project i ended up needing another broach - i need a 3/16" broach with a 5/8" collar for the motor pulley
03:18 PM roycroft: i ended up getting a shars broach and collar, and that came to less than $50 for both
03:19 PM roycroft: my experience with shars is that their stuff is made in asia, but it's decent quality
03:19 PM roycroft: and it ships from the us
03:21 PM roycroft: dumont would have cost me close to $150 for the same thing, and close to $100 used
03:22 PM roycroft: and the used ones rarely come with shims, so there's another $20 or so for shims
03:22 PM roycroft: the shars seems like a good value, especially considering that i likely won't use it often
03:22 PM roycroft: although it's a good size to have
03:23 PM roycroft: my boring bar that i was going to use originally is larger than the diameter of the bores, so that idea is out
03:23 PM roycroft: it would have worked with my original idea of going direct from the motor to the spindle
03:56 PM JT-Shop: roycroft, do you want that motor mount powder coated satin black?
03:56 PM roycroft: how much extra would that cost?
03:57 PM JT-Shop: $10, I'll do it with these other parts I'm fixing to powder coat
03:57 PM roycroft: sure
03:57 PM roycroft: that's great
03:57 PM roycroft: it will be better than my painting it
03:57 PM roycroft: thanks
03:58 PM JT-Shop: tossing another part in the oven and not changing color is piece of pie
03:59 PM roycroft: what's the default ip address of a mesa card?
03:59 PM * roycroft just powered up his pi and mesa card, and wants to see if the mesa card is alive
04:00 PM JT-Shop: did you set the static ip for the rpi?
04:00 PM roycroft: no
04:00 PM roycroft: that's why i want to know
04:00 PM roycroft: so i can set the ip on the pi
04:00 PM roycroft: also so i can ping it once i do
04:01 PM roycroft: i'm loading up the manual, but i figured asking here would be faster
04:01 PM roycroft: ok, i found it
04:02 PM JT-Shop: set the rpi to or anything but which the mesa card is set to if jumpered correctly
04:03 PM roycroft: yeah, and i'm not pinging the mesa card
04:03 PM roycroft: so i should check the jumpers
04:03 PM JT-Shop: use my 7i96 tool to talk to the mesa card
04:03 PM JT-Shop: aye
04:04 PM roycroft: i just want to ping it right now
04:04 PM JT-Shop: open my 7i96 tool and press F1 on the machine page for help
04:05 PM roycroft: i don't have a gui interface right now
04:06 PM roycroft: my laptop is in the other room - i just ssh'ed to the pi
04:06 PM JT-Shop: W5 Down W6 Up
04:07 PM roycroft: yeah, they were down down
04:07 PM roycroft: they are down up now
04:07 PM roycroft: if "up" means towards the center of the board
04:07 PM roycroft: if "up" means towards the edge of the card, they were both up
04:07 PM JT-Shop: up means the Mesa word is not upside down and the card is vertical
04:07 PM roycroft: if "up" means towards the edge of the card, they were both up
04:08 PM JT-Shop: if I didn't flash it then they would both be down
04:08 PM roycroft: anyway, i can't talk to the pi anymore - i suspect adding the static network config disabled dhcp on the wifi
04:08 PM roycroft: so i'll have to lug a console out to the shop to fix that
04:09 PM roycroft: i'm killing time waiting for a vm image to copy
04:09 PM roycroft: i needed to copy it to a hypevisor in a datacenter
04:10 PM roycroft: the network interface to access that hypervisor is in private address space, behind a firewall that's connected to the outside world via a 256k dsl link
04:10 PM roycroft: i have to use the stupid vmware vclient that only runs on windows to do this
04:10 PM roycroft: it spent five hours copying, and was 80% finished, when windows rebooted to install some updates
04:11 PM roycroft: so i had to start all over again
04:11 PM roycroft: and this is one of my windows installs that i keep telling to *never* update
04:11 PM roycroft: but it keeps ignoring me after a while
04:13 PM roycroft: hmm, maybe the reason i can't ping the pi is because i forgot to turn the power back on
04:14 PM roycroft: ok, i can ping the mesa board now
04:14 PM roycroft: i'll configure it later - my immediate goal was to ping it
04:16 PM roycroft: leaving the board jumpered to does not impede my ability to do anything else, does it?
04:17 PM roycroft: other than not being able to change the ip without reflashing it, that is
04:21 PM JT-Shop: aye is the best, you can do anything you need from the rpi
04:22 PM roycroft: i see no reason to change it
04:22 PM roycroft: and if that's the only thing that cannot be changed with the jumpers in that position, then it's the best way to set the jumpers
04:24 PM roycroft: if i'm honest, my more immediate interest is in getting linuxcnc to talk to the rpi gpio pins
04:24 PM roycroft: i both don't have my high voltage components yet for doing motion control, and know that configuring the mesa card will be straightforward
04:25 PM JT-Shop: it should be simple to make a config to control the rpi pins
04:25 PM Tom_L: on that one it is
04:25 PM JT-Shop: oh by the way I improved the rpi tool a lot this morning
04:26 PM roycroft: good to know
04:26 PM roycroft: i'll clone it again
04:26 PM JT-Shop: version 1.0 is much more intuitive to use
04:26 PM roycroft: you did what andy suggested?
04:26 PM JT-Shop: and more
04:26 PM roycroft: cool
04:26 PM roycroft: it will be a bit
04:27 PM roycroft: i'm doing os updates right now, and there are a lot of new ones
04:27 PM JT-Shop: https://forum.linuxcnc.org/27-driver-boards/43907-rpi-4-gpio-calculator
04:27 PM roycroft: hopefully today's upgrades won't hose things for linuxcnc
04:28 PM roycroft: the update to 10.11 sure failed, though
04:28 PM roycroft: but i won't worry about that if the machine comes back
04:29 PM roycroft: this is just a scratch install for testing anyway
04:30 PM roycroft: which is good, because it's not coming back
04:35 PM roycroft: i would say that updating to 10.11 on the pi is not a good idea
04:35 PM JT-Shop: debian?
04:35 PM roycroft: the bootloader keeps trying to cycle through all the devices it thinks it can boot from
04:35 PM JT-Shop: or raspberry os
04:35 PM roycroft: and displays "firmware not found" for each one
04:36 PM roycroft: i'm using andy's image, which is raspberry os
04:36 PM roycroft: i think
04:36 PM roycroft: but this is good, in a way
04:37 PM roycroft: i discovered that i had not logged all my changes to the changelog, so now i get to rebuild from scratch and make sure i do log all changes
04:41 PM roycroft: is there an os you recommend for the rpi?
04:42 PM JT-Shop: https://gnipsel.com/linuxcnc/uspace/
04:42 PM JT-Shop: I used a lite with openbox
04:44 PM roycroft: i'll give that a go
04:44 PM roycroft: i've almost always used raspbian on my pis
04:45 PM roycroft: but i really don't keep track of all the oses people run on them
04:46 PM roycroft: btw, in case anyone is interested, adafruit just got a batch of rpi4b with 8GB of ram
04:46 PM roycroft: they won't last long
04:54 PM CloudEvil: https://thepihut.com/collections/raspberry-pi/products/raspberry-pi-4-model-b?variant=31994565689406 also
04:54 PM CloudEvil: - first other vendor ichecked
04:56 PM JT-Shop: that is raspbian but the lite version
05:05 PM Tom_L: i nearly forgot how to build a bit file
05:07 PM roycroft: everybody must have just gotten them back in stock
05:07 PM roycroft: when i bought mine recently i had to check a dozen or so vendors before i finally found one that had a 4GB version, and those are sold out now
05:08 PM roycroft: or were
05:10 PM roycroft: ups were just here
05:11 PM roycroft: the driver - the one who always notes "handed to mr man" - said to me "this is the third day in a row i've delivered to you. am i going to have to start coming here every day now?"
05:11 PM roycroft: in a fairly snotty tone
05:11 PM roycroft: isn't their whole reason for existence bringing parcels to people?
05:11 PM roycroft: if she didn't have to come here, or elsewhere, why would she still have a job?
05:12 PM roycroft: on the other hand, it's the longest conversation i've ever had with her
05:16 PM Tom_L: count it as a plus
05:17 PM Tom_L: mmm pcw isn't here
05:18 PM Tom_L: i wonder if i can drive an opto from a fpga pin
05:18 PM Tom_L: probably but it would be good to hear a 2nd educated opinion
05:19 PM JT-Shop: when I built my plasma I ran the geckos straight off the 5i20
05:19 PM Tom_L: really?
05:19 PM Tom_L: ok good to know
05:20 PM Tom_L: then i can free up an io and be good to go on the A axis step/direction
05:20 PM JT-Shop: aye, didn't have the money for a daughter card and ran it that way for years
05:20 PM Tom_L: heh
05:21 PM Tom_L: then i can keep all the 'functions' on the first header and gpio on the rest
05:24 PM roycroft: i should be clear
05:24 PM roycroft: it's the most words she's ever said to me
05:24 PM roycroft: i just said "thank you" as a response
05:24 PM roycroft: which is all i ever say to her any more
05:46 PM -!- #linuxcnc mode set to +v by ChanServ
05:46 PM -!- #linuxcnc mode set to +v by ChanServ
06:10 PM solarwind: roycroft what belt grinder do you have?
06:10 PM solarwind: I'm looking into buying one or making one
06:11 PM roycroft: i built one - the first version of jeremy schmidt's
06:11 PM roycroft: i would recommend version 2 though, and in fact i recently purchased plans for v2
06:12 PM solarwind: Ok thanks, I'll check that out
06:13 PM roycroft: it's the best belt grinder design i've ever seen
06:13 PM roycroft: i put a 3hp motor on mine, and i think that's the perfect size motor
06:16 PM roycroft: building it will also give you a great excuse to play with your welding gear
06:37 PM solarwind: I've really been liking bronze brazing lately. If I had a zinc deficiency before, I can tell you I definitely don't anymore :P
06:38 PM tiwake[m]: brazing is kinda fun
06:38 PM solarwind: As a bonus, burning off the zinc from the brazing rod leaves behind copper. I
06:38 PM roycroft: i have that supplied air respirator now
06:38 PM solarwind: So yeah, I never could figure out why they're called bronze brazing rods. They're RBCuZn
06:38 PM solarwind: roycroft yeah I bought a PAPR helmet, the optrel one. I love it
06:38 PM roycroft: so no welding fumes woudl bother me
06:38 PM roycroft: since i won't inhale them
06:39 PM solarwind: Bronze is copper + tin right? The brazing rods are copper + zinc which is brass
06:39 PM roycroft: traditionally it is copper + tin
06:39 PM roycroft: there are generally other metals present as well
06:39 PM solarwind: https://weldingmaterialsales.com/catalog/rbcuzn-c-low-fuming-bronze-bare-and-flux-coated/
06:39 PM roycroft: and there are "bronze" alloys without tin
06:40 PM roycroft: copper + aluminium
06:40 PM roycroft: i'm not sure if silicon bronze has tin or not
06:40 PM solarwind: The common low fuming bronze rods are very much a brass alloy
06:40 PM roycroft: but basically copper + tin = bronze and copper + zinc = brass
06:40 PM solarwind: silicon bronze is for tig brazing. https://weldingmaterialsales.com/catalog/ercusi-a-silicon-bronze/
06:40 PM solarwind: It has a tiny bit of zinc and tin
06:41 PM solarwind: But the bronze rods are definitely brass, not bronze, so I'm not sure why they're called bronze
06:44 PM roycroft: i've heard nickel welding rods referred to as "cast iron rods", because they're used to weld cast iron
06:44 PM roycroft: perhaps it's similar with the brass "bronze rods"
06:46 PM roycroft: anyway, two things i really like about the jeremy schmidt grinder are that there are so many attachment arms that can be made for it, and uniquely, when the grinder belt is tilted the table remains stationary
06:46 PM solarwind: Yeah cast iron TIG welding rods are either 55% nickel or 99% nickel depending on how ductile/machinable you want it ot be
06:46 PM roycroft: welding on cast iron is generally a bad idea, especially with ductile iron
06:46 PM roycroft: but folks do it
06:47 PM roycroft: brazing is vastly superior to welding when it comes to cast iron
06:47 PM solarwind: I've done it on my ductile iron vise with no problems. But yes I agree, brazing cast iron is much less stressful
06:48 PM roycroft: when you melt ductile iron it gets hard and glassy and brittle when it solidifies
06:48 PM roycroft: basically, you just don't want to ever melt cast iron
06:48 PM roycroft: so braze it
06:48 PM solarwind: Yeah if it cools too quickly, it hardens. But if you preheat and post heat, you can manage that
06:49 PM solarwind: But yes, brazing is easier because it avoids all that
06:49 PM roycroft: and on small parts that's fairly doable
06:49 PM roycroft: but it's hard to pop an engine block or a bridge port mill knee in an oven
06:50 PM roycroft: unless welding on cast iron is your thing and you have some really big ovens
07:34 PM roycroft: well the stock raspbian distro upgraded to 10.11 fine, so it was probably the rt-prempt kernel that fouled things up before
07:46 PM roycroft: i suppose i should be taking effectively snapshots as i build this machine - after every major step, shut down, pull the ssd, and dd it onto my nas as an iso image
07:46 PM roycroft: it's pretty slow to install updates and the like
08:18 PM skunkworks: JT-Cave: starlink is amazing..
08:49 PM roycroft: i've not seen anything on the forum about linuxcnc on bullseye, and i'm so far behind on the mailing list that i really don't know if folks have succeeded in running it
08:49 PM roycroft: does anyone know?
09:02 PM roycroft: some guy just knocked on my door and said "did you get some mail that wasn't for you? i ordered a hot tub and the post office said they delivered it here because i was not home."
09:02 PM roycroft: i told him i have received no deliveries recently that were not for me
09:02 PM roycroft: and he said "are you sure? they said the delivered it a day or to ago - can you check?"
09:03 PM XXCoder: rather diffult to miss hot tub
09:03 PM roycroft: i'm pretty sure that no hot tub was delivered to my house
09:03 PM roycroft: and just as certain that the usps do not deliver hot tubs
09:03 PM roycroft: they're a big larger than what they handle
09:03 PM XXCoder: yeserday I got anti-delivery
09:03 PM XXCoder: some lady went in and stole a pot
09:04 PM roycroft: i've never seen this person before, either - he's not my neighbor
09:04 PM roycroft: the post office would not have delivered anything to a neighbor if the intended recipient was not home
09:05 PM roycroft: and certainly not to some random house
09:05 PM XXCoder: btw https://media.discordapp.net/attachments/602938910947016730/898444340114915338/unknown.png
09:05 PM XXCoder: that lady and soon to be stolen pot
09:07 PM roycroft: installing the preempt-rt kernel did not work, btw
09:07 PM roycroft: the pi is hanging while booting
09:07 PM XXCoder: can read logs?
09:08 PM roycroft: just the console
09:08 PM roycroft: it's not fully booting
09:08 PM roycroft: the console shows that it can't find the gpio bus
09:09 PM Tom_L: you didn't want to use the iso?
09:09 PM roycroft: i'll try again after dinner, but takes a couple hours to build a kernel
09:09 PM roycroft: it's old
09:09 PM Tom_L: you can update it
09:09 PM roycroft: i tried that and it failed
09:09 PM Tom_L: i did and am running 2.8.2 on the rpi
09:09 PM roycroft: which is why i tried jt's method of installing raspbian and then building a preempt kernel
09:09 PM Tom_L: you have to uninstall 2.8.1 pre
09:10 PM Tom_L: change the sources list and reinstall 2.8.2
09:10 PM Tom_L: if i can do it anybody cad
09:10 PM Tom_L: can
09:10 PM roycroft: it's not linuxcnc that's failing
09:10 PM roycroft: it's linux
09:10 PM Tom_L: get a bad download?
09:10 PM Tom_L: that's what i did
09:10 PM XXCoder: checked crc?
09:10 PM roycroft: i want something fairly current, especially since the letsencrypt problem
09:10 PM roycroft: the initial install goes fine
09:11 PM roycroft: it's upgrading from 10.8 or 10.9 to 10.11 that fails
09:11 PM Tom_L: mine is about as current as you can get
09:11 PM Tom_L: mmm
09:11 PM Tom_L: that i'm not sure of
09:11 PM Tom_L: i'm not one that needs the bleeding edge stuff
09:11 PM roycroft: i don't need bleeding edge
09:11 PM Tom_L: i did do updates though
09:12 PM roycroft: but i need a distro that does have the current root certificates
09:12 PM Tom_L: but i can't tell you what buster version it is off hand
09:12 PM roycroft: i'm curious about linuxcnc on bullseye
09:12 PM Tom_L: i haven't heard of any support for it yet
09:12 PM roycroft: and if folks said that they've done it i might give it a go, early in this build
09:13 PM roycroft: but i'm fine with buster
09:13 PM roycroft: i'm still waiting for a relay that i need before i can wire up the high voltage part of my controller
09:13 PM Tom_L: http://buildbot.linuxcnc.org/buildbot/builders/0000.checkin/builds/8224
09:14 PM roycroft: so i'm configuring the pi in the meantime
09:14 PM Tom_L: bullseye isn't in the build list yet
09:14 PM roycroft: i won't bother trying bullseye then
09:14 PM roycroft: but i would like 10.11
09:14 PM Tom_L: but it looks like master just passed the build
09:23 PM roycroft: what i get is a bunch of this: "firmware:gpio: Failed to get GPIO 0 config ..."
09:24 PM roycroft: where GPIO 0 cycles up to 7, and the repeats the sequence
09:24 PM roycroft: and a few other errors
09:24 PM roycroft: then it hangs
09:27 PM roycroft: i need to look at installing kernels on debian again - i recall having to reconfigure grub for a new kernel when i've done this in the past, and jt's guide does not do that
09:28 PM roycroft: it may not be necessary - i'm not saying his guide is wrong
09:28 PM roycroft: i should probably try to build it using 10.9, and then perhaps do the upgrade to 10.11 later
09:37 PM roycroft: i think jt's guide misses a step, based on a rpi preempt-rt kernel build site i'm looking at