Rather than MDF, I ended up getting five 6' pieces 1" square steel tube, for the router table
robin: depends on your drive
robin_sz: if it's a drive with tach feedback there's a tach feedback loop too.. I think
owad: is 1" gonna be stiff enough?
I suspect that you could set the ends of one of those on blocks, step in the middle, and get an inch of deflection with not even your entire weight
I'll try that
it is very easy to get into a "how stiff is stiff 'enough'" mode, and I'll be the first to admit I don't know how stiff a router table needs to be
I have a tendency to overbuild things
build it on a surface table
that ought to be 'stiff' :P
ds2: its already built
I can. But if I stand on two, I get almost no deflection. I'm going to have 5, and will only be putting wood on top of it
it just needs the worktable
then use one granite table from an old CMM
owad - that kind of hands on test is worth more than an hour of me talking ;-)
be sure to get a precision level on one end and check for deflection by pushing on the far end ;)
and since it's steel, I'll be able to tap holes, rather than trying to use those threaded inserts
I think this'll last a lot longer
are you going to put MDF on top, or just use the rails by themselves as your table?
but steel can only be so stiff ;)
I can't decide.
how thick is the wall of your steel tubes?
I'm going to have _some_ sort of sacrificial material betweent the steel and the workpiece, so probably a full sheet of MDF
I'm remembering some 1" home depot tube that had less than 1/16" wall
this measures .068"
not a lot of thread
I was thinking I'd go through both layers
you won't get any strength from the far side
two sheets of metal with air between them, when you tighten the second sheet bends a tiny bit, and the first one takes all the load
I was just looking in mcmaster - $8.02 for 25, 1/4-20
2 boxes would let you put 10 nuts in each of 5 rails, that would mean a nut every 4.8"
I've never used riv nuts. Are they difficult to install?
with an installer tool, not at all
if you have a tool, easy.. if you use a bolt and wrench, it could get tricky
they can be a pain to install without the tool, by inserting a screw and tightening
another thing I was thinking about is steel piping
25 1/4-20 with stuff left over for $9.99 @ harbor frieght
(assortment pack of 6-32,8-32.10-24. and 1/4-20)
or get the tool with 10 1/4-20's for $16.99!
which one? I'm seeing a lot of rivetrs
1210 is one
94100 is the combo one that claims to also do rivets
fwiw, the 6-32's tend to strip instead of set with the tool :(
ds2: with which one?
I have the 1210; so that one... donno about the 94100
the bigger ones seems to work okay
dont get hardware from harbor freight
it's made of chewing gum
get the $16.99 tool from HF, then get the rivnuts from mcmaster
Is something wrong with the HF rivets?
if it is important, don't use the HF rivnets
they will hold up initially...just further on down...
owad - their steel has more in common with cheddar cheese than real steel
* jmkasunich <- fastener snob
stop insulting chedder cheese.. ;)
Think any place local is likely to have them? I can't find them in Lowe's catalog
hard to say - dunno where you are, but unless you are very impatient, just order from mcmaster
I've seen it at some industrial surplus places
jmkasunich: can this kind of motor run safely at a range of rpms? It doesn't have a "max" marking. http://timeguy.com/cradek-files/emc/spindle-motor.jpg
within limits ;-)
you might need external cooling..
the low end is limited by cooling - as built, the motor is cooled by a shaft mounted fan, if you slow it down you will lose cooling
as sam says, you can fix that with a external constant speed fan
at the high end, the limits are mechanical
from zero to "base speed" (the nameplate 60Hz speed) you have constant torque, so HP is proportional to speed
above base speed, you have constant HP
how far above base speed you can go depends on two things
1) mechanical limits (balance, flying apart, etc)
2) breakdown torque - as speed goes up, the nominal torque drops, to maintain constant HP - but the breakdown torque (the torque at which the motor "stalls") drops even faster
you should be able to get 2:1 constant power range without much trouble, 4:1 is not uncommon
since the motor is low RPM to start with, you most likely won't hit mechanical issues for at _least_ 2:1 as well
1) mechanical limits (balance, flying apart, bearings etc)
right, forgot bearings
you probably will want to _remove_ the shaft mounted fan and rely on an external fan for cooling, at least if you are going above base speed
shaft mounted fans consume HP (and generate noise) as the cube of the speed
so it provides inadequate cooling below nominal speed, and turns power into noise above base speed
the original design was constant speed, so it wasn't an issue
the two gear ratios I have are 4:1 with each other
you're golden then
so if I want 3000 rpm top (original spec), I should set the varispeed so it's 3000 when the motor is at about what - 1500?
you can go for 2:1 constant power and 2:1 constant torque, which will give you 1HP at the bottom of each range, going to 2HP and the middle of each range, and remaining constant up to the top where you shift
you aren't planning to increase the nominal top speed (probably a good idea)
no, 3000 is fast enough
but you can increase the motor speed (don't have to, but if you use the vfd to _decrease_ the motor speed, you lose HP)
so, what to do....
the varispeed was about 4:1 range?
so overall you had 4:1 in low, then shift and 4:1 in high, total 16:1?
the ranges were 150-750, 600-3000
so varispeed was 5:1
ok, and they got some overlap
you are content with the existing range, right?
but you don't want to use the varispeed because you want EMC to be able to control the speed
yes. in fact I doubt I will use low range much.
how did the old control vary speed? actuators for the varispeed? or was that manual?
it ran the varispeed with a ballscrew
is that mechanical stuff (including motor) still there?
why not use it?
I want css
sounds like a job for hal.. ;)
EMC should be able to control that
ok, enough of that
you'll have to decide how much of the 4:1 speed range you want to get by going below base speed, and how much by going over
(also, how much, if any, overlap between ranges - that will increase the range the VFD needs to provide)
then you run the motor at whatever you intend its max speed to be (say 2200), and adjust the varispeed till the spindle is doing 3000, then leave it
note that increasing the motor speed will increase the speed of everything in the drivetrain that used to be constant speed - belts included
that means more power loss to belt friction, and more belt wear, not that either of those should be too severe
you really will get more power at the spindle if you use the varispeed in addition to the VFD, but that can be a later enhancement
ditto - time for another round of scrapinf
jmkasunich: a big problem with varispeed is it has to be running to change. that means no starting at a slow speed if you were previously at a fast speed. I think it would be enough of an ongoing pain in the neck that it's worth even losing some range and/or power.
for an unusual setup I could still always change it.
one thing I meant to bring up
you said "I don't think I'll even use the low range"
don't be so sure
I might just leave it as-is and have a hardwired switch to change it.
lathes sometimes spin big stuff (far bigger than any milling cutter)
yes definitely true.
if you are working on something 6-8" in diameter, you won't want to be spinning too fast
200 RPM at 6" is 314 SPFM - HSS in steel would be toast, HSS in aluminum would be pushing it - that is well into carbide territory
interesting that the slowest speed (150) is still pretty fast. I think this lathe is meant for pretty small stuff.
it is a chucker after all
goodnight for real now (last time was going to walk the dog)
I'm setting up my first emc2 machine now
latency-test gives me a max jitter of 26484 on the servo thread
now it just jumped to 39143
I'm using a 1.8 GHz motherboard with an old ATI Rage II+ video card
What should I look at to decrease the jitter?
did you turn off all the power saving options in the system bios?
Hmmm, I don't remember. I'll check that in a minute
what video driver are you using?
[04:06:23] <cradek> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?TroubleShooting#RTAI_Latency_test
some stuff here, some is more up to date than other
I'm not sure. Xorg.conf doesn't say! I haven't seen that before...
I'm using Xubuntu 8.04 BTW
yeah that's a new "feature" of xorg
I bet you can find in /var/log/Xorg.log
Guess I'll look in the log file...
it might be worth it to try forcing Driver "vesa"
Looks like it's using ati_drv and mach64_drv
the card is a mach64
Can vesa do resolution over 1024?
I'm a little surprised there's still a driver for those
vesa is generally slower. it will be an interesting data point if nothing else.
ok. I'll try changing the driver and check the BIOS. I'll have to reboot to do that, so I'll see you later. Maybe tomorrow since it's pretty late here
here too. goodnight.
Looks like the jitter went down to 13283 with the vesa driver
but the screen doesn't look near as good. It's darker and grainier
I did have power save disabled in the BIOS
so hostmot2 does have step generation?
untill i'm able to fetch a 24DC psu, i can just use a computer PSU to drive 12V steppers,.. it 'l just be slower,.. right?
basicly depends on the motors
12V .4A 4-lead bipolar 4W 1.8° stepper motor
brant is ITC model ITC-CNC-1 (only found a french datasheet of it)
silly bugger costed me 30 euro,.. expensive stores :'(
[18:36:45] <alex_joni> http://fantasticcontraption.com/
alex_joni: thanks for the great link, your fault if I don't get no work done today
dushantch: yeah, I know how it is :D
I can't pass stairs :(
* alex_joni is at big ball
* dushantch is on big ball too after some hair pulling ofc
hm.. I'm not there yet
what stage is that?
* dushantch passed it now :)
dunno, doesn't say :)
I just got to big-ball
hmm seems a good job it didnt work on my pc
* alex_joni passed big ball
alex_joni: these 4 balls sre tough :)
im at around the bend
dushantch: indeed.. did you pass it?
alex_joni: not yet, now trying to make a carriage for them :)
mission to mars im at now
anonimasu: just 2-3 more to hair pulling
i think this one is hard enough
dushantch: wanna see something fun?
alex_joni: I got them to the second side but can't get them in lake
[20:09:30] <alex_joni> http://imagebin.org/23899
alex_joni: congrats, I'm cursed that I want the least clicks solution, also known as lazy
alex_joni: does it work?
up the staiers..
I have one in the lake :D
yes.. it worked !!!!
mine is funnier, a beer whoever gets how it works :) http://imagebin.org/23900
* alex_joni already got it to work :D
next is down under
alex_joni: I had to do it my way: http://FantasticContraption.com/?designId=331059
funny thou that it works
dushantch: bad paste?
alex_joni: works for me, that's what you get when you register
works for me too
I didnt register
I meant you can save position like that when you register
hmm.. didn't work for me :)
got to awash yet?
nope, still down under
trying to build a pendulum
dang - I just managed to finish 4balls
hmm not much going to be machined today
dushantch: hint: you need to make a moving pendulum
I was only taking pics of my bits today
alex_joni: am trying
alex_joni: thank god I don't have much work today or this would really upset me
it's close to midnight here :)
alex_joni: here too
time to go play with guns
say goodnight gracie
alex_joni: I've got 1/2 ball in but can't get further :)
I beat down under
I'm always close, but can't get the whole ball in, just a part
* alex_joni thinks awash is harder
want a hint?
not anymore :D
dig like a worm - yellow wheels on bottom, pink ones on top
[21:24:28] <alex_joni> http://imagebin.org/23902
oh boy, "handling" looks tough
that's what I had
I had about 6 pink wheels on top, otherwise similar
cmon I'm still on down under
I couldn't get more elegant than this http://FantasticContraption.com/?designId=331774
ha, beat handling
jmkasunich: cool.. I'm still struggling
jmkasunich: only 3 levels left
jmkasunich: how did you do handling?
two cars, one going right, one left
the right one had a wooden floor that caught the falling thing that I had to carry
both had chains tied to corners of the thing
when the chains came tight they pulled it upright again
had to tweak lengths to get it upright at the same place
what game is that?
[21:48:24] <jmkasunich> http://FantasticContraption.com/
Ironically, I JUST found (MS-DOS) Increadable Machine last week
Well, got the safe moved over... now too tired to even look at it =)
jmkasunich: 1 car stupid but works solution http://FantasticContraption.com/?designId=332094
dushantch: those links don't work for me
I use firefox
so do I
hmm.. tube seems hard
I tried and works in other browser, copy/paste :(
I get a screen complaining about flash version, when I bypass that it just starts the game again, without showing me your thing
anyone know anything about solaris?
a-l-p-ha: I know some solaris, whats up ?
jmkasunich: so far all I managed was to get it out of the house zone
ha, I got it!
ah, don't tell me
I think I know
two yellow wheels against the right wall, two pink against the left, brace the bottom yellow against that lump down there
Dallur, trying to ssh to a solaris box, with putty, and the home and end keys are giving me ~
vertical links, and angled cross links, such that weight develops side force
it crawls up the walls
a-l-p-h-a: what shell are you using on the solaris box ?
a-l-p-h-a: here is a detailed guide on how to rebind keys depending on which shell you are using: http://188.8.131.52/search?q=cache:219u3ip2QrkJ:www.google.co.kr/answers/threadview%3Fid%3D27006+solaris+%22home+key%22+%22end+key%22&hl=is&ct=clnk&cd=1&gl=is&client=firefox-a
I tried with only 3 wheels
a-l-p-h-a: that link might not have the exact solution but essentially you might need to rebind the keys although if memory serves me right if you have bash on the solaris box everything should be passed through
a-l-p-h-a: that is if you have bash and are using it
jmkasunich: any luck with back and forth?
I managed to grab the ball, but I can't carry it far
and now I can't even grab it
Dallur, yeah, it's bash
Dallur, that link is for csh
? I could be wrong...
just edit ~/.bashrc and put in the following line:
bindkey "\e[1~" beginning-of-line
bindkey "\e[4~" end-of-line
those two lines should map end and home
I managed to get it to the right of the green.. but not up the slope
bindkey "\e[2~" overwrite-mode
bindkey doesn't exist on the server
bindkey "\e[3~" delete-char
thats end and delete
a-l-p-h-a: just use bind
just figured that out
a-l-p-h-a: all sorted out ?
jmkasunich, I'm stuck on higher
jmkasunich: I managed to throw the ball in the hole to the right
higher? is that a level?
I just got to umpossible
higher is a level.
oh, I mixed you up with alex
got it too :)
Dallur, hmm... if after bind '"\e[4~":end-of-line'; and then I type "^" and then hit end it works.
a-l-p-h-a: but not loaded from .bashrc ?
is it now.!
Dallur, thank you!
a-l-p-h-a: np :)
this page is wicked. http://www.geocities.com/h2428/petar/bash_bind.htm
boo!!! alt-backspace didn't owrk
neither did backward-word/forward word
There's a reason for my hatered of electronic locks, and that just proved it!
jymm: what did?
Like most electronic locks, they have the battery compartment on the outside so you can change it if it's low.
Ok, if you enter in the wrong combination, there's a 2 second delay untill you can try it again.
If you enter in the wrong combination three times, it locks oyu out for five minutes.
with me so far?
Now, if you open the battery compartment, it's a 9V battery. If you unclip the battery and just hold it in your hand you can hold the contact together with your fingertips
Noe, if every time you enter in a wrong combination, the second it says error, release the contacts and the 2S delay is removed, and completely voids the 5 minute lockout
what a piece of shit lock
I can get this thing open in a couple of hours if I had something to push the buttons for me.
it only has 100,000 possible combinations.
jmkasunich: any ideas?
tried a catapult and a ramp - nothing seems able to get on top of the green platform
I got the ball ontop of the green platform
with a catapult like thingie
but I can't get it around the edge
and adding a chain makes it too heavy
jymm: well, locks can be picked..
normal ones too..
well, I was able to lauch a "car" onto the roof
of course it went flying off the far end
how did you launch it?
anonimasu: But you can't remove the two exposed screws, exposing the electronics, then look up the datasheets online in 10 minutes =)
with a complicated ramp arrangment
wheels don't have enough traction to climb the ramp
so I put a pink wheel on the roof, and a second upside down ramp with weights on it
[23:31:12] <jmkasunich> http://FantasticContraption.com/?designId=331774
jymm: no, however it'd still take a few tries..
anonimasu: Yeah, but not minutes.
you are forgetting that they still need to guess.
anonimasu: With the electronics removed, there are three wires leaiding inside the safe. I'm just looking up the pinouts so I don't short out anything.
I'm not sure if you guys noticed, but you can connect to the outside of the pink wheels, and then it acts like a rotary piston sorta thing.
[23:44:27] <alex_joni> http://imagebin.org/23905
it worked :D
shorter wheels on the car :D
hmm.. there is nothing else after this
the car climbs the ramp while the other wheels are making the ramp go up?
and the car is fastened to the end of the ramp
with the chain
* alex_joni just wasted 3h :(
if you say :D
you posted the URL at 14:35, its now 19:35
lets say 2h were justified