[rowbare]

You need one home switch per axis. With Mach, these can be wired together though some other systems might require them to be wired separately. One would wire them together to save on inputs when using the parallel port. If you are using the SmoothStepper, that shouldn't be an issue. The limit switches can be wired together. The limit function is agnostic as to what axis direction caused a stop. You will be able to see that for yourself.

In your case you have a big table so you might want to run separate home and limit switches. In fact you might want to home your x and y around the middle of the table and apply an offset value. On a big table with slow rapids you can save a lot of time by doing that. Home isn't necessarily the Zero position.

bob

[diyengineer]

OK so i previously bought about 9 honeywell limit swtiches from Jameco for $15 bucks (they were red and black). They were really nice little quality units. Now Jameco doesn't carry them and i cant find them anywhere!! It seems like all the Honeywell limits that i find are HUGE and $45 dollars a piece! Where can i find just the small micro switches that are 1-5 dollars and are Honeywell brand. I dont really want to trust my gantry breaking all because a chinese limit switch failed.

If anyone knows please let me know!

[brunog]

Diyengineer,
Do you have a part number of what you are looking for?
Have you tried Mouser and Digikey? Mouser sells Honeywell, Omron and microswitch products

Best regards

Bruno

[diyengineer]

Diyengineer,
Do you have a part number of what you are looking for?
Have you tried Mouser and Digikey? Mouser sells Honeywell, Omron and microswitch products

Best regards

Bruno

No i don't, they appeared just like normal small cheapy looking limit switches like the .99 cent ones with the 1" arm, except they were really quality units made by honeywell red/black in color. Can anyone suggest or shoot me a link to ones that are known to work well? I just want a name brand unit that will work when it needs to. I'm sure the cheapy ones work, but i cant afford to take any chances.

[Al_The_Man]

What you need to look for is Honeywell-Microswitch hermetically sealed roller top 914CE2-9 style or similar, they are pricey but try ebay, I have got real deals in these.
If you use an open style LS for $5.00 don't expect performance over the long term.
These are a common switch of choice in commercial equipment.
Omron make the same version also.
Al.

[diyengineer]

What you need to look for is Honeywell-Microswitch hermetically sealed roller top 914CE2-9 style or similar, they are pricey but try ebay, I have got real deals in these.
If you use an open style LS for $5.00 don't expect performance over the long term.
These are a common switch of choice in commercial equipment.
Omron make the same version also.
Al.

I will look! One site was selling them for $80 bucks a piece, ouch i need 6

[Al_The_Man]

Are you running Mach?
Three limits can do OT in each direction and home with 3 switches in series and take up one input.
Al.

[diyengineer]

Yes i have Mach. I thought i needed 6 switches to limit the 2 directions of travel on 3 axises? haha Now you have me all confused Al! Maybe you are talking about the homing switches only needing 3? Hmmm..

CNC4PC got back to me and said his photo sensors (for homing) can be easily extended and work well.

Maybe i will use those for homing and some cheaper simple honeywells as limits(the $3 dollar a pop ones), since if i program everything correctly they should not be coming in contact with very much since they will be placed at maximum travel of each axis, right? Wrong? lol



Thanks.


Also finishing up with the new 125AMP panel install. check it. Now i have to run all the wires and install the rest of the breakers for all the machines and receptacles i want Hopefully be lucky enough to finish that up tomorrow then run hard air lines everywhere. I'm thinking copper tubing for the air, and solder the joints. I've done the whole PVC thing and dislike it (had a few close calls and 150psi blow outs). I would do steel pipe but don't want to deal with the rust and corrosion. So copper i guess it is?

[diyengineer]

Instead of using mechanical limits at all can i use, "Inductive Proximity Switches".

I believe they need a ferrous metal to work. Since the machine is mostly aluminum i would have to apply some steel cubes, but alteast i wouldnt have to worry about a mechanical failure.

Fairly cheap as well. ($10USD a piece) x 6 limits= $60 bucks.

http://www.dmm-tech.com/Pricing.html

Those as my limits and then use the photo sensors as my homes? what do you think is best Al? I might as well get all high tech :P

**http://www.engineershandbook.com/Com...itysensors.htm
Loads of info!

[rowbare]

You might find this thread interesting: http://www.cnczone.com/forums/showthread.php?t=101878

This is one of the better articles on limit switches: http://pminmo.com/home-and-limit-switches

bov

[Al_The_Man]

Yes i have Mach. I thought i needed 6 switches to limit the 2 directions of travel on 3 axises? haha Now you have me all confused Al! Maybe you are talking about the homing switches only needing 3? Hmmm..
.. since if i program everything correctly they should not be coming in contact with very much since they will be placed at maximum travel of each axis, right? Wrong?
. I've done the whole PVC thing and dislike it (had a few close calls and 150psi blow outs). I would do steel pipe but don't want to deal with the rust and corrosion. So copper i guess it is?

I have only set up Mach as a test so I have not used it, but I am sure others will correct me that you can set up one limit switch in the middle of each axis travel, with a striker dog each end.
When you home Mach it searches for the home limit which also acts as an OT limit, but as the function is homing, it homes only, after each axis has homed in turn, then the limits act as O.T. limits.

I don't believe you can use copper for air, I would not, I have seen it rip open quite easily.
Steel pipe will last for many years and you can always paint the outside.
Or use Galv.
Al.

[diyengineer]

I have only set up Mach as a test so I have not used it, but I am sure others will correct me that you can set up one limit switch in the middle of each axis travel, with a striker dog each end.
When you home Mach it searches for the home limit which also acts as an OT limit, but as the function is homing, it homes only, after each axis has homed in turn, then the limits act as O.T. limits.

I don't believe you can use copper for air, I would not, I have seen it rip open quite easily.
Steel pipe will last for many years and you can always paint the outside.
Or use Galv.
Al.

Nice i will look into using the galv, or steel!

I finished wiring the sub panel like a pro! luckily im still alive haha! Tomorrow i have to string out new circuits!

[diyengineer]

I have power! Everything went well! Now time for air!

Then back to building the beast.

[diyengineer]

I have a 20 gallon 6.5 horse shop vac that im hard piping in as well. So i wont have to roll that sucker around the shop. I might as well right?! lol

[eded59]

i have seen copper used in a lot of the factories in my area. I ask a plumber on the job about it and he pointed me here
http://www.copper.org/resources/pub_...e_handbook.pdf

[brunog]

I don't believe you can use copper for air, I would not, I have seen it rip open quite easily.
Steel pipe will last for many years and you can always paint the outside.
Or use Galv.
Al.

Copper is often used in factories in our part of the world, but nowadays instead of soldering the fittings together some plumbers will braze them.

Best regards

Bruno

[rowbare]

There is a current thread on HSM regarding air distribution: http://bbs.homeshopmachinist.net/showthread.php?t=42795

bob

[diyengineer]

[nomedia="http://www.youtube.com/watch?v=KJV__eJoZh0"]YouTube- ‪A Few Shop Upgrades.‬‎[/nomedia]


Finally 95% done with the shop renovations. Just need to hang & wire some lights that i already have and im golden... well at least for awhile haha.

finally ready to make some real progress on the machine, school is out for the summer!

sorry the video is from my htc droid eris cell phone, not the usual FLIP HD camera.

[diyengineer]

Dug into the rails today just to figure out the spacing between the rails. I started with a .035" gap using a feeler gauge, and worked down .001" all the way to no gap. I recorded my findings based on feel initially since im lucky enough to have the gear out of the gantry. Between .010"-.020" felt good. I accidentally pushed down super hard on the gear at one point and thankfully since i wiped the steel rails down with a enormous amount of oil one slipped just a hair! The gear basically set up the gap for me, right @ .014". THANK GOODNESS. I did a test run and bolted an entire side down all spaced .014" apart from each other and the gear clears each meshing rail perfectly, so nice you cant even feel the transition!

Im using socket cap bolts (steel) 8-32 x 1 1/4", they prolly only enter the aluminum threaded hole about .25". For steel going into a aluminum threaded hole, what is the recommended TQ? (there are no heli coils in the rail beds FYI, all aluminum, unsure of temper or type).

I bought a Tq wrench though and would like Tq them all evenly.

I guess im after the dry torque spec without lubrication (anti sieze). Would semi permanent loctite be considered a lubircant, or would i still use the dry spec?

[diyengineer]

coming along... hope to have the ball screw in tonight possibly?.. well see!

Gear and drive train in. ball screw support in, top linear rail in.

Now for the carriage and ballscrew.