CNC Mill #2

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JimGlass
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CNC Mill #2

Post by JimGlass » Thu May 15, 2003 10:04 pm

I'm back at it again building another bench top cnc mill bigger and more rigid than the first machine. The head will be mounted to a 6" square steel colum and a moveable ram to increase reach in the "Y" axis. The head "Z" axix will move in square gibs and will have 5" travel. The table and saddle moves on linear ball bearings on Tompson shafting. "X" axies travel is 26" and "Y" axis is 14".
Image
I'm using 550 oz/in stepper obtained where I work. They are changing them out with servos. The steppers will drive from a Gecko 201 driver board, already ordered. I'm using 1/2-10 acme threaded rod for feed screws. I spoke with Mark at Gecko and he figures these steppers and feed screws would have enough power to jack up a car. I guess the machine with self destruct if the travel bottoms out.

Just finished hardening and grinding the spindle shown on the machine table. I used a-2 tool steel. The spindle will only accept endmills with 3/8 shanks or smaller. Sorry, no collet system this time.

I hope this design will be rigid enough to cut steel. Hardly wait to try it out but with summer approaching and vacations it could be a while.
Image
This is the first CNC machine originaly built for another project. Notice the head is not a rigid design running up and down 1" Tompson shafting. Then the spindle extends 10 out from the 1" shafts. Very smooth running but not rigid under a load.
Jim
Tool & Die Maker/Electrician, Retired 2007

So much to learn and so little time.

www.outbackmachineshop.com

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Marty_Escarcega
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Re: CNC Mill #2

Post by Marty_Escarcega » Fri May 16, 2003 12:16 am

Boy Jim, I sure admire you building them from scratch. Your work looks great!
Marty
"Jack of all Trades, Master of None"

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AndrewMawson
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Re: CNC Mill #2

Post by AndrewMawson » Fri May 16, 2003 2:34 am

Great work Jim, where do you find the time?

How are you supporting that table? From the photo it looks as though the the aluminium slab spans for its entire length - is there something to stiffen it?
Andrew Mawson
Battle, East Sussex, UK

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FrankG
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Re: CNC Mill #2

Post by FrankG » Fri May 16, 2003 5:44 am

Hey Jim,

Most intense,,, It is inspiring to see what other folks are doing.

Your initial mill was one of the inspirations for me to begin the journey into CNC (which I'm just starting...)

Frank
http://www.theworkshop.ca

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JimGlass
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Re: CNC Mill #2

Post by JimGlass » Fri May 16, 2003 5:59 am

Thanks for all the compliments.

Andrew: Your right about the table spanning it's length. I will address that later. I'm going to mill a 2 shallow pockets
on the underside and mount 2, 1/4 x 1 x 36" brass strips. Then the aluminum blocks that retain the linear ball bearings will have a steel strip of hardened toolsteel for the brass to slide against. I'll do the same with the "Y" axis. This way there is no vertiacal deflection. The steel part will most likely have a channel ground to retain the sides of the brass strips as well. I did this on the first mill and worked out very well.
Thanks for the interest,
Jim
Tool & Die Maker/Electrician, Retired 2007

So much to learn and so little time.

www.outbackmachineshop.com

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len
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Re: CNC Mill #2

Post by len » Fri May 16, 2003 12:59 pm

Great inspiration, Jim. Glad to see someone actually designing and building these things. As a "retired" software/computer engineer working with controls, I know how much time it takes to actually finish such a project, so my admiration goes out to you. Please take extra time to document your work so the rest of us can benefit.

len

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