Low cost CNC machine, is it worth it?

[Qboiler]

https://www.maslowcnc.com/

i cut some form blocks with my cheap performax band saw, and was not satisfied with the quality, so was looking at alternatives and was really thinking hard about just buying the hydro formed ribs and spar from bearhawkaircraft but my brother sent me the link above. For about $500, it looks like a potentially viable poor man’s CNC. My numbers still come out higher than just buying from Bearhawk, which is about $3700 for professionally made part, with no spoilage... but for the dedicated plans builder it still might be good?

Any thought or has anyone tried it? The one cool thing I liked was once someone had good data files they could be easily be shared.

[rodsmith]

I started out as a dedicated scratch builder. Now I advise anyone that asks, buy as many pre made parts as you can afford. You will be glad you did as the years roll by.

[davzLSA]

Amen to that brother, my education on that cost me about $3000 and about 400 hours of time, you really need to pick your battles and there is no shame in buying parts.

[way_up_north]

https://www.maslowcnc.com/

i cut some form blocks with my cheap performax band saw, and was not satisfied with the quality, so was looking at alternatives and was really thinking hard about just buying the hydro formed ribs and spar from bearhawkaircraft but my brother sent me the link above. For about $500, it looks like a potentially viable poor man’s CNC. My numbers still come out higher than just buying from Bearhawk, which is about $3700 for professionally made part, with no spoilage... but for the dedicated plans builder it still might be good?

Any thought or has anyone tried it? The one cool thing I liked was once someone had good data files they could be easily be shared.

ive been accused on here of not being gentle with my opinions or advice... so read this post with gentle classical music playing in the background ..sipping hot cocoa.....

...does this unique cnc method copy acutely across the whole width of the form... if I remember correctly it’s more accurate in some areas then others...maybe that’s been fixed ..if not do not use this method

You have a few choices... spend good coin on a traditional x y axis machine you might only use once...

become an expert tool and die maker(wood) like the rest of us on here(make a rib form 3 times you’ll get good)

or buy some of the best ribs in the buissness...the most recent pictures of ribs from the factory show what consider the sexiest ribs I’ve seen .... there is is not a hint of distortion ... you’ll have a perfect airfoil... no flat spots

or break out the roll of cash for an accurate machine

or break out the disk sander and make and re make form blocks till you are the master of all you survey

few years back ... I would not let a hamster ride in anything I could scratch build... now after trial and error... I can make a form block within half a millimeter accuracy in any direction measured ...the cheapest method is you become the machine

avipro ribs are balls on accurate.... with a scientific replication of the ribblett airfoil

any part you make on a machine still has to be checked for accuracy...

[Mark Goldberg]

The ribs we have professionally hydroformed are made by the same company that makes the RV ribs. We could probably save several hundred dollars on each kit by having one of the factory workers make ribs as done by you scratch builders. You would think one worker making ribs all the time could get pretty good at it. But we like the professionally hydroformed ribs because they look so nice. Mark

[S Lathrop]

I have a decent machine shop behind my house. I have a lathe, CNC mill, press brake, couple drill presses, band saw and both gas and TIG welding equipment. That is to name just a few bits of machinery.

Beyond the drill press my hand tools are what I use most on my project.

When I need to make something that is both complex and needs to be accurate, I make a drawing of the part and get it printed full size. I then glue that drawing to what ever material I am making the piece from. I cut, sand , file to get the part I want. In short, I find this has been the best method for me to make parts and I don't need the shop I have to build this project. But if you make friends with a machine shop owner to do the few jobs that might exceed your capabilities and resources you will be way ahead in this project.

[fairchild]

Keep in mind too--- the bed of the machine has to fit the biggest parts you want to do---- the main center ribs are 3 feet long. Probably more parts longer than that in the fuse.

I am just using ( I HOPE :-) ) good take-your-time machine shop practice..... and I would say my ribs might be easily within .010 variation -- or maybe a little less--- not as pretty
as the 100 Ton hydroforming machine that the factory uses--- but good for just some guy making them ---- and plenty fine I think for their intended purpose.

That would be a LOT of green to tie up for so few parts. Most people I have heard of with them run them night and day - 24-7 to make them pay for themselves.

T

[svyolo]

We had a CNC at a metal supply warehouse I worked at in college. The warehouse was probably over 20,000 sq feet. That very rudimentary (1984) CNC machine made more money than the rest of the warehouse. If they had the work, it worked around the clock.

CNC machines have come a long way, and come way down in price. But they still cost quite a bit, and take up a lot of shop space that can't be used for anything else. It is a nice tool, but not one I have ever considered buying. I would probably get a mill and lathe first, and I am no where near buying either of those.

If I was going to scratch build, I would at least buy the pre-bent spars, and without a machine shop, any machined parts. I might make the ribs myself.

Or make two, and buy the rest from Mark.

[spinningwrench]

I have two CNC machines in my shop and use them extensively for making parts for my Bearhawk Patrol. Little metal parts that things line up perfectly on. large parts, I just finished making the wood floorboards for my Patrol. Small CNC's can make big parts provided you can slide and re-index the part in a new location. An alternative for say form blocks is to take you air foil design in any CAD format to a woodworking shop with a large CNC mill. They can cut you a form block accurate to within .005". I will admit the hydroformed ribs from Mark are a thing of beauty.