G0704 Power Drawbar Overview

This is a detailed overview of my custom designed power draw bar for the G0704 mill. The assembly fits on the stock head with stock motor.

[@michaelbrocato7535]

Sweet setup and I love the detailed explanation...job well done

[@Lspe7]

Great job. Looking to do something similar on my KX3 cnc. Most of the videos about the pneumatic drawbars do not explain the concepts as well as yours.

[@SurfyKirky]

I’m sold really made it easy to understand how they work. A design or kit would be awesome

[@darkobul1]

cool man. Lot of work but nice design. You have demystified to me hole thing.

[@GuyFawkes911]

thanks great video.

[@TMCmakes]

i would love to see drawings, but after hearing that it took you a year to implement, maybe i'll just buy a cylinder and build a housing for it! i love building stuff for the mill, but i love building stuff WITH the mill even more.

[@ChristopherJones16]

04:27 I’m having trouble following how the draw bar lifts up by being pressed on downwards. Is it actually being lifted up or only appearing to be lifted up because the washers are being pressed down creating the illusion the draw bar is lifting up?

[@LionSandwich]

The plate is the reaction force for the Bellevilles being compressed by the changer piston.

[@Brute4rce1111]

I was thinking about making my own but it looks pretty complicated 😅. Have you thought about hydraulics? Possibly a small pump power pack with a 1.5" hydraulic cylinder?

[@LionSandwich]

It was complicated. Don't do it😂

[@772777777777777]

Thanks for explaination and overview of your design very helpful

[@joat_mon]

Nicely done! Thanks for sharing. I'm considering going down the 3D printed power draw bar rabbit hole too. What are some of the major issues to overcome using plastic components? What I'm considering is using some metal parts to overcome the limitations of the 3D printed parts. Thanks again, nice design!

[@LionSandwich]

Don't do it. I've sank way too many hours into failures. Plastic simply isn't stiff enough to create reasonable sealing surfaces.

[@joat_mon]

@@LionSandwich I hear ya. Safety and flying plastic shrapnel come to mind too. It's an engineering puzzle that I can't help but to ponder though.

[@rc-cnc3431]

Interesting concept. How much force did it produce @90 psi

[@LionSandwich]

1500lbs

[@minasianjohn]

Hi, I'm very interested in making one of these you have done a nice job in designing and building it. I'll say I like this concept more than the pneumatic Harbor Freight version. If you have the specs and the sketch ,I would be interested in buying it from you. Thank you kindly. John

[@ChristopherJones16]

Is that the one that uses the air ratchet?

[@homemadetools]

Nice, subscribed! If you want more subs, feel free to embed your video on our homemade tools forum; looks like you're one of us :-)

[@mr1enrollment]

if I am not mistaken, the series connection of pistons does NOT multiply the force. rather only the linear deflection/motion of the piston is 'multiplied'. the force remains: F = (pi*r^2) * air pressure = (3.14*(3/2)^2) * 90 = 424 lbs-force, which sounds light to me. What is the spring rate of the washers?

[@LionSandwich]

No. Think of it like there is 90psi on all exposed area of piston. In this condition the "affective" piston area is your calculation x 3.

[@mr1enrollment]

@@LionSandwich ok I see it now.