Re: G0704 extended Y axis??
The table on a G0704 itself is 7.125 or so wide and the Y base is 13.25. If no overhang was allowed as is stock, the travel would be in the 6.125 range. 8 is possible with over travel occurring on both ends (possible due to the stepper mount and the column spacer. 12" would be impossible without an entirely different base. An inch or 2 of engagement of the gibs is not enough.
I think you must have got onto the Charter Oak/Industrial Hobbies site to see 12" Y travels.
Re: G0704 extended Y axis??
Quote:
Originally Posted by
Jim27
Looking at getting at G0704 to CNC. The HF 44991 is more in my budget but the Y axis is too small. Does the G0704 ever go on sale?
I have looked at some extended Y axis info on the G0704 and getting more than 8" would be a real plus since a few things I want to do are 8" across. I have seen some claim just over 9" (which would be enough) and just ran across this that states 12". No real info though without signing up so I didn't do it.
Making a CNC Milling Machine - Increasing the travel - THE MAKERS GUIDE
I am guessing the 12", if possible, is not recommended due to poor support at the extremes?
My real question is about ball screw conversion. If I go for the extended Y axis (9+") do I need longer ball screws? If so, where can I get them? Or do I need to machine the ends myself for this?
Bill (Makers Guide) based his build from the files I sent him, My G0704 has 12" of travel but seldom use it usually stay in the 8" range.
Here is my build log.
http://www.cnczone.com/forums/bencht...97650-cnc.html
I also have a few videos on youtube.
Re: G0704 extended Y axis??
Quote:
Originally Posted by
Jim27
My real question is about ball screw conversion. If I go for the extended Y axis (9+") do I need longer ball screws? If so, where can I get them? Or do I need to machine the ends myself for this?
Yes you need a longer y ballscrew to get up to 9.5" y travel.
Y Axis up to 9.5 inches, Z Axis up to 18 inches
I suggest getting ballscrews from linearmotionbearings on ebay, Chai will machine the ends to whatever specs you provide.
Hoss
Re: G0704 extended Y axis??
I should have clarified, the files I gave to Bill was only to accomplish the 12 extended travel, all the other files came from Hoss2006. His DVD's that I and Bill both bought.
Re: G0704 extended Y axis??
Mine is set up for 10" Y, I highly recommend doing the rear mounted stepper motor, makes future mods and enclosure much easier and requires a longer ball screw which would have to be purchased again of you decide to change it later.
I did 10" because it put the spindle centered on the table mid travel when using the rotary table head 5th axis mod.
I wouldn't go over 10", if you need more, I would look at the charter oaks mill as stated above. I actually would go that route regardless because it's just a better mill to start with and well worth the extra money.
I love my G0704, but I'd sure have started with the larger mill if I had it to do over again. Once you start extending the column off the base with spacers and the head, you start losing rigidity pretty quickly, that column is just too small and the way it mounts is rather weak. It does allow the extensions the way it's designed, but you'd be far better off getting the travels in a mill designed for it.
Just my thoughts.
Chris
Re: G0704 extended Y axis??
Thanks for the replies. For comparison I was checking out some old Bridgeports. Thy Y travel (or at least the table size) was 9". For example, several were described as 9 x 42. Was thinking the Y would be more. One of the drawbacks is they weigh about 3000 lbs and the thought of moving something like that is daunting. How does a G0704 CNC project compare to getting a Bridgeport (or other similar old mill) for hours and cost invested? Maybe get a Bridgeport CNC with old/defective controls and update the controls reusing the motors and position feedback? I've got a motor control background which would help on the controls upgrade.
Re: G0704 extended Y axis??
Quote:
Originally Posted by
Jim27
Thanks for the replies. For comparison I was checking out some old Bridgeports. Thy Y travel (or at least the table size) was 9". For example, several were described as 9 x 42. Was thinking the Y would be more. One of the drawbacks is they weigh about 3000 lbs and the thought of moving something like that is daunting. How does a G0704 CNC project compare to getting a Bridgeport (or other similar old mill) for hours and cost invested? Maybe get a Bridgeport CNC with old/defective controls and update the controls reusing the motors and position feedback? I've got a motor control background which would help on the controls upgrade.
A 9x42 knee mill has a 9" x 42" table. Travels are typically longer in Y, shorted in X. Most 9x49 knee mills have about 11-12" Y travel, and 32-34" X travel. Knee mills make lousy CNC machines....
Regards,
Ray L.
Re: G0704 extended Y axis??
Vertcnc is selling his converted MD001 with automatic tool changer ready to run for a pretty reasonable price. That is the long table rf45 model. You might be miles ahead of the game going that direction. Building one from scratch can be frustrating if it's your first mill because you will need to machine the mill itself to be able to install ballscrews, mounts etc....
Not to mention the tool changer and drawbar is a very useful add on. Check his name for posts... He also has some videos on YouTube, pretty cool!
Chris
