routers and blades

[jacquesm]

Today I tried to get a 1:5 model of the blades out of a chunk of wood to see what kind of troubles I'll run into when I try the full scale one. I wrote a bit of python to give me a 'job' file that the plasmacutter program will accept, ran into a few bugs in the software (I never tried true 3D work yet), and fixed them.

I rigged a clamp to an ancient black & decker router, ran a few tests and then set it up to route the front side of the model.

It works, but the finish is pretty rough (lots of runout on the bearings of the router) especially near the root portion of the blade where it bites pretty deep into the wood. Eventually we'll be routing foam, so I don't think it will be a problem, but right now it looks real ugly in some places. Also the blade is 'backwards', if you were to make a windmill with this one it would spin counterclockwise, I have changed that in the software to get a 'proper' blade.

It's funny how I was totally confused as to how the blade actually sits on the hub, I somehow pictured it with the airfoil portion pointing *into* the wind, but that's not the way it should be. I checked Hugh Piggott's book one more time and found out that I did indeed have it completely backwards...

One big problem that I don't have a good solution for is how to make sure that the blade top and bottom portion will 'register' properly when I flip over the base material to route the other side.

The cutter table looks pretty rough right now (some rust even!), I haven't gotten around to painting it any further because I'm too busy with the windmill, I hope to get to that in the winter. It is in its current state because I recently redid the whole gantry system to reduce vibration (the trusses make it much lighter).

The blade profile is a little wider at the tip than the norm, that's to keep the noise level down. If there are strong reasons for narrow tips other than weight reduction then I'd like to know about it. I have heard some narrow tipped blades and I'm amazed at the noise levels they put out, some really scream (especially plastic injection molded blades). The wider ones seem to be much more quiet.

Another - minor - gripe is that the router bit is flat at the tip, I could not find a ball shaped bit that has a long enough cutting portion to do the whole job (unless I cut the profile in several passes, but in foam the nice thing would be to route the whole thing in one go). This 'flat' portion causes a dimensional error in the steeper portions of the cut.

pictures follow:

The router clamp, it fits the toolmount on the z axis slide of the cutter:

Side view of the router mounted on the slide:

Top view:

Halfway into the cutting:

Finished front side (but reversed):

Semi intelligent vacuum cleaner mount:

[Norm]

   Looks pretty good so far! When I ran across the part where you pictured the design backwards ...just think of the possibilities! You could make dozens of blades.....All Wrong!

       No sarcasm here...just light hearted humor!

  I think a lot of us have got confused on this at one time or another.

   No need to tell you to have fun...looks like you already are!!

                   ( :>)  Norm.

[jacquesm]

hehe, that had me laughing out loud here (strange looks for s.o.). Reminds me of a joke where two scientists are looking at the output of a huge computer and the one says to the other do you realise that it would take a 1000 humans armed with pencil and paper at least 10 years to make such a colossal mistake ?

Another name for the same phenomenon is garbage in -> garbage out !

[drdongle]

Once you get this perfected you could have a neat little business making blades for other people. They down load the software, calculate their blade dimensions and then email the results back to you. You then make the set, and drop them off at UPS for delivery. Oh and get a nice little check.

Carpe Vigor

Dr.D

[LEXX]

I like your machine, and really want one!!  What would that unit cost?  Where do you live?  If Canada or states you could order the proper router bit from LEE VALLEY, they have pretty much every thing.  Oh yeah, I was looking at the last pic, aren't you a little young for power tools, I have to complement you on your writing style tho.

LEXX

[jacquesm]

I live in Northern Ontario (St. Josephs Island). Pretty much as rural as it gets while still being within a school bus area. I have no idea what a machine like this should cost, but if you are serious then I'll have a look at what goes into it in parts and labour. This is a fairly heavy machine (200+ pounds for generator + governor + slipring assembly), it will sit on a 60 foot tower on top of a hill.

Hehe. That was my son helping his dad, he's ok around the workshop (but I wished he'd be more disciplined about the safety glasses... I only noticed that when I saw the picture on the site, never even crossed my mind that he was right up to the router bit).

Biggest issue with fabricating this beast so far was making laminations. It took three of us three days (that's 9 mandays ! working hard !) to get them up to spec after the raw cutting. Someone else here suggested laser cutting, which would make things a little cheaper, possibly. Or maybe I could invest in a laser head if this gets serious. For now the diy option gave me lots of flexibility, the airgap on the original design was so tight that any blade would stall the moment that thing cut in, right now it's a bit on the large side and I wonder if I will be able to shut it off completely with the short circuit switch (there is that 60 feet of cable acting as a nice little heater in that situation). We'll see where this goes.

You're free to copy the design (I'll post cad files of all the parts when I'm sure that's it), I have absolutely no idea where this is going and if it's going to work or not but it sure does look good. It still is absolutely untested, has never been in the weather and I'm sure to run into tons of snags (which is pretty much the story of this whole project), so it is probably better to wait for a bit to see how I fare. No need to duplicate my mistakes

We have the winding/coil insertion down to something workable, but I'm sure it could be done a whole lot better. 'Zubbly' has a writeup about rewinding an AC motor for pm conversion which makes my stuff look like childrens work, but then again he *is* a pro (and we *are* a bunch of children, even if a little older).

With a proper winding diagram any motor rewinding shop should be able to do that part for you anyway, it's just that I wanted to do this one myself because the motorshop here in town messed up the winding of the scale model. They said there was not enough room for the copper, I pretty much proved them wrong with the stator of the real machine. I was pretty sure it could be done, and we don't have a head or a coil winding machine (just a pegboard). I do have an idea for a CNC based coil winder that will wind these puppies right on the stator, that should take the sting out of the whole operation.

Pleased to meet you, and thank you for the kind words.

[brett]

I am very interested in your router/cutter table. Did you use plans from here

www.machinetoolcamp.com? I was thinking of purchasing the 5x10 table plans, wondered if you had any experience with them.

You are obviously very talented, nice looking work.

[jacquesm]

I designed and built the table from scratch (this is version 2, lets just say I learned a lot , if I were to build another one I'd make some changes, but not a lot. If you want I can make some drawings and post them, but it won't be soon because I'm busy making the windmill right now. I do have some pictures up at ww.com, they are of the machine before the changes but it gives you a good idea of what it looks like and how it works.

[brett]

I see.... So the blue machine was first one and the unpainted-really nice one with the router is the second one? I would really appreciate any information that you could spend the time posting, whenever you find the time. I can understand structure and relationship to moving parts on basic level using pictures and could build to approx. size by copying, but could not even begin to guess at size and type of motors, bearings, controllers, pc interface equipment needed. An unreasonable expectation to post all inclusive info on sizes part numbers etc, in my opinion, of course unless you sell plans like the www.machinetoolcamp.com plans to recoup on your efforts. What is your opinion on those www.machinetoolcamp.com plans, say the 5x10 cnc router plans? I am not trying to be a nosy person or a stalker, please forgive me if this offends you, but under that LOCATION post earlier on the discussion board i noticed you are in northwestern ontario. I am right next door at winnipeg beach , Manitoba. Lots of Canadians eh. Good luck on your wind generator building, sounds like it will be a powerfull unit. I am looking forward to following your progress. Thanks again for sharing everything so far.

[jacquesm]

Hi Brett,

'Generation One' was inded the nice, pretty blue machine, we spent a few months building it, then a few more testing it and we found that it had some serious shortcomings (vibration, maximum speed and moving weight), so we redesigned the gantry system, and that is the machine I'm using right now. If I would make another one it would be pretty much the machine I'm using now with some slight modifications.

I'm using it with homebrew software, but it will work just as good with the 'Nist' software.

As soon as the windmill is up I promise to make a detailed plan on how to build the cnc router/plasma cutter wiht lots of detailed pictures and part numbers. I hope to have my machine up and running before the first snow, so I'm burning every hour I can right now, but give me a few weeks and you will have all that you want (and then some I'll make the plans available for free.

I have not looked at the site you mention, but I will do so.

Winnipeg ?

I heard a funny thing that mentioned Winnipeg on the radio a week ago, it said:

"Canada has 3 1/4 world class cities, Vancouver, Toronto, Montreal.... and Winnipeg in the spring"

Take care there.

  Jacques.