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Birth of a 4-axis CNC machine #4: Linear Rails - WOO HOO! - eBay doesn't totally suck after all.

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Blog entry by DS posted 03-21-2013 09:39 PM 1695 reads 0 times favorited 14 comments Add to Favorites Watch
« Part 3: How lovely are the feet! Part 4 of Birth of a 4-axis CNC machine series Part 5: Bet you thought I gave up on this... »

Just won these on eBay!

I’ll bet most of you gave up on this build!
This will be for the main x-axis which will carry the gantry.

There’s enough resources (read money) left to buy the A xis motor, gear head, chuck and tailstock.
After that it’s back to the waiting-for-money game. :-(

If only the clerk at the 7-eleven would stop selling me the LOSING lottery tickets this would go faster.

Expected delivery March 27th
(I feel like a proud Papa)

—————————————————————————————————-

UPDATE:

Score another one for eBay!

This is a 100:1 planetary gear box with a NEMA 34 Stepper motor.
It will become the drive for my rotary A axis. that takes me from 200 steps per revolution to 20,000 steps per revolution. SWEET! And for the auction price of $72, it can’t be beat.

This should arrive in the next week or so.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251



14 comments so far

View DIYaholic's profile

DIYaholic

13581 posts in 1333 days


#1 posted 03-21-2013 11:30 PM

Ok, ya got linear rails…..
Length?
Brand?
Guides?
You know, what are the vital stats???

Oh yeah…
Congrats on the score!

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procratination a bad thing?

View SPalm's profile

SPalm

4820 posts in 2540 days


#2 posted 03-21-2013 11:36 PM

Sweet. Those look really nice.

Sigh, real linear bearings. If only I had…

So only a few more things to buy :)

Steve

-- -- I'm no rocket surgeon

View Joe Lyddon's profile

Joe Lyddon

7732 posts in 2710 days


#3 posted 03-22-2013 12:32 AM

Still… very interesting…
Thank you.

-- Have Fun! Joe Lyddon - Alta Loma, CA USA - Home: http://www.WoodworkStuff.net ... My Small Gallery: http://www.ncwoodworker.net/pp/showgallery.php?ppuser=1389&cat=500"

View DS's profile

DS

2131 posts in 1078 days


#4 posted 03-22-2013 05:35 AM

Okay I was in a hurry before when I posted.

Here is the skinny:
They are THK rails 1960mm long (77”)
Each rail has two SR20 Bearing blocks on them

I know, I know there are a lot more things to buy, but, this is a significant step forward in the right direction.

Next step is to assemble the A-axis. I’m looking at a used 100:1 reduction gear box with a Nema23 stepper motor for $70…I would need a chuck and a tailstock to complete the assembly.

Baby steps… I’ll get there.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View DIYaholic's profile

DIYaholic

13581 posts in 1333 days


#5 posted 03-22-2013 01:51 PM

DS,
You obviously have a “plan”, but are you adjusting said plan “on the fly”, for your purchases, or are you just purchasing according to the plan?

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procratination a bad thing?

View DS's profile

DS

2131 posts in 1078 days


#6 posted 03-22-2013 03:17 PM

There IS a plan, but it is a flexible plan. These rails are longer than what I need and I will cut them down. The remaining portion of rail might be useful for the Z axis if I can get a couple more bearings for them.

More than a plan, I have a vision in my head of what I want to accomplish. There are multiple options that are suitable for my purpose, so, as certain opportunities arise, like these rails, I will exploit them as best I can.

I had in mind to purchase a 4th axis head with the chuck, gear box and stepper motor all in one. That option is about $280. Then I saw this used gearbox with a stepper for $70. I would just need to make a mounting plate and add the chuck and I’d be good to go.

The pre-assembled chuck was a 3 jaw chuck and that really isn’t what I want on this unit, so I’d be replacing the chuck anyways. There is an advantage as well that the used gearbox is 100:1 where the full unit had only 8:1 gear reduction. For the relatively large diameter turnings I see myself producing on this machine, the bigger reduction gives me more fine resolution.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View DIYaholic's profile

DIYaholic

13581 posts in 1333 days


#7 posted 03-22-2013 05:24 PM

Sounds like a “PLAN” to me.
That is how I do everything.
Picture it…
Purchase supplies…
Start the build…
Then WING IT!!!

With so many variables involved in such a complicated build, I tend to get “Analysis Paralysis”!!! I end up more undecided (& confused), with the more research I do!!! It doesn’t help matters that I’m not an engineer or an electronics geek!!!

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procratination a bad thing?

View DS's profile

DS

2131 posts in 1078 days


#8 posted 03-22-2013 06:16 PM

That’s just it— I’ve been analyzing this build for 15 years already.
Time to just do it.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View JL7's profile

JL7

7206 posts in 1623 days


#9 posted 03-22-2013 09:49 PM

Nice score…..

-- Jeff - I have not failed. I've just found 10,002 ways that won't work.

View Dave's profile

Dave

11168 posts in 1498 days


#10 posted 03-24-2013 10:44 PM

What are the cahnces of that.

-- Superdav "No matter where you go - there you are." http://chiselandforge.com

View DS's profile

DS

2131 posts in 1078 days


#11 posted 03-25-2013 03:53 PM

I just scored a Gear box for the A axis. (See the update in the OP.)

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View DIYaholic's profile

DIYaholic

13581 posts in 1333 days


#12 posted 03-25-2013 03:57 PM

Nice score on the gear box!!!

That should provide enough resolution!
How many Pixels??? Lol!!!

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procratination a bad thing?

View DS's profile

DS

2131 posts in 1078 days


#13 posted 04-02-2013 06:51 PM

Well, the Rails and the gearbox are here… There is so much more to buy and do that I can hardly decide which direction to go next.

I’ve been looking to buy my Y-axis rails and I keep getting the nagging feeling that I’m going to want the machine to be wider than it currently is.

That means buying longer 8020 t-slot material, longer rails etc.

I think it will be worth it to be able to machine larger width panels. (36” vs. 24”)
The current size is a funciton of the t-slot rails that I was given and not the purpose-built machine I am looking for.
Hmmm. It’s just money I guess.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View DIYaholic's profile

DIYaholic

13581 posts in 1333 days


#14 posted 04-02-2013 11:02 PM

I agree, IT IS ONLY MONEY…..
Thankfully, it is YOUR money & NOT mine!!!

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procratination a bad thing?

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