Step 22: Propeller Pt 3/4 - End Cone

The end cone is the attachment to the hub that makes the assembly more aerodynamic (or hydrodynamic) when travelling through a fluid. The base diameter is 2" to match the hub diameter and the height is 2" chosen to give a streamlined surface without being too long. The overall shape is a parabola what has been reloved around a central axis.

To build it a plug was machined from 1" polystyrene foam in two halves (Photo #1). 0.05" was left at the bottom to stop the parts coming loose on the last pass (Photo #2, I need to learn how to use the holding tabs feature in CamBam when I get the time). The two havles were then glued together using a thin layer of white glue after the swarf was removed with a utility knif and some 220 grit sandpaper (Photo #3).

To give the endcone a hard durable shell I covered it in a layer of fiberglass using the vacuum bag method using the following steps:

-I assembled the materials in Photo#4. I was working outside with good ventilation to protect myself from the fumes.

-I measure out the epoxy in to 2:1 ration of resin to hardener using the measuring cups. Shown in Photo #5 is 15ml of mixed epoxy, I ended up using 30ml.

-Starting the fiberglassing I wetted out a piece of fiberglass cloth 3"x3" (larger than the cone's base) onto the piece of waxed MDF. Photo #6

-Next I placed the foam endcone plug in the middle of the wetted fiberglass. Photo #7

-and draped a piece of fiberglass cloth over it. Photo #8

-I wetted out the cloth until all areas were saturated with resin. In Photo #9 I still have creases in the cloth. These will not lay flush even after vacuum bagging so small slits will have to be cut in the fiberglass overlapping the edges to smooth the material out.

-Next an oversized piece of peel ply is layed over the fiberglass. Photo #10

-And then a layer of breather cloth (Photo #11). I put an elastic band around everything at this stage to hold it all together while I made the bag. Photo #12

-I placed everything on one side of the vapour barrier (Photo #13) and doubled the plastic over sealing the edges with duct tape while inserting an air line from underneath the breather cloth and out a corner (Photo #14)

-The exit point of the air line is the hardest place to seal. I used plasticine around the airline as shown in Photo #15. This takes a long time to get right an is quite frustrating. The next time I vacuum bag something I will take the time to make a proper sealed connection using brass fittings.

- A vacuum is now applied using a pump made from this instructable. With this setup I can pull up to 25" Hg.

-After 24 hours to let the epoxy cure the part was taken out (sorry, forgot to snap a picture of this step), the excess glass cutoff around the bottom, a coat of primer applied and sanded to be flush with the propeller hub. Photo #16

-When I was happy with the fairing (more a function of the time I had available than the results, it could have been a lot better) I gave it a couple more coats of primer. Photo #17

-I cut out a recess on the bottom and using autobody filler attached a #6-32 nut and washer. I covered a 1/2" long #6-32 machine screw in Vaseline to prevent the autobody filler from sticking to it and assembled it through the mounting hole in the propeller hub (Photo #18). This makes it possible to remove the endcone from the top side of the hub. I later decided that removing it wouldn't be necessary so I faired the hub and endcone together with drywall compound and made them one piece.

-Using metalic autobody spray paint I had on hand (Photo#19) I gave the endcone/top hub assembly and the bottom hub three coats of paint followed by a layer of clear coat. Photo #20
<p>Hola, tienes un dise&ntilde;o del equipo mejorado actualmente?, costo?</p><p>Tiempo de entrega?, costo de env&iacute;o?, requerimientos d hardware y</p><p>software,? etc.Estoy en M&eacute;xico, D.F</p><p>Tel.52- 5555-27-21-21</p><p>movil. 044555-4196924 Gracias.</p><p><br></p>
<p>I see this was made 3 years ago any improvements since then ? and could you use nema 23 with this build </p><p>thankyou</p><p>Richard Westerfield </p>
<p>Anyone know how to size/pick the timing belts and pulleys?</p>
<p>Approximate cost?</p>
<p>What driver board did you use? </p><p>Thanks</p>
<p>I am working on a similar project. But it's a laser cutter.</p><p>Neat project! </p>
<p>Great Job Nick.</p>
<p>I built one, cost $750 and has a cutting area of 3'x3'x4&quot; you can see my videos in Youtube under my name bubalettow</p>
<p>Why you worked in the unit inch?</p>
<p>i wonder where you put the usb or any communication cable to communicate between the CNC machine to the PC *i assume this CNC controller is PC-based. and if there is, where di you pluh that cable on the machine? directly to the stepper motor or add an additional built-in controller. Thanks</p>
<p>Excelent work</p>
<p>Hi Nick, this is such a good instructable. I have a little question if you don't mind. I noticed that in the plan of left-right gantry sides one of the holes (where you attached limit switch) is missing. Do you get that hole later after installing everything or you just forget to draw it? Or maybe its position is given different on the plan?</p>
<p>Nice work bro. :)</p>
<p>Is this 130 oz-in unipolar rating of the stepper motor? And will the dimensions change if we use any other motors....</p>
<p>Hi everyone, I'm getting a lot of messages asking if I have a 3d model for this project. Unfortunetly I don't. I only have the 2d dimensioned drawings attached in the steps.</p>
<p>amazing work </p>
thanks thanks thanks .... so much... <br>ill try its
great article!!! very informative!!!
Just to let everyone know, i am working on a sketch up of this project (minus the custom sled hardware) to be made with standard length aluminum extrusion, and all 3/4mdf (for ease of construction and rigidity). if you would like a copy let me know <br>
A great project! I would like to have access to your latest mods and CAD drawings. <br> <br>Thank you, <br>
I'm interested in this sketch up. I'm about to rebuild my CNC.
Here is a list of my modifications so far. I have not finished the mock-up so this is not the final list <br> <br>Moved mount for y axis motor up 4 inches <br>changed gantry assembly for moved motor mount <br>replaced bearing block with alernitive gantry sides <br>shortened overall gantry height for added clearence <br>modifed track for easier assembely <br>modified ider bearings for timing belt security <br>modified base for new tracks and timing belt tensioner <br>changed belt tensioner to 3/4 mdf
I'm looking forward to seeing your modifications. My one suggestions would be to avoid using MDF if you can. I used it on my first machine for cost reasons and found it to be less than ideal as is its much heavier and not nearly as stiff as ply.
The reason that I wanted to do this in all mdf is because it is half the price of 3/4&quot; ply. This is also just to be able to have a machine that i can use to cut more sturdy, expensive woods, such as the 3/4&quot; ply or other soft lumber (because a 1by is actually 3/4&quot;). <br> <br>These modifications are only for a first machine to make the better machine, not for a really long term use (put it together, make new parts, replace, repeat) <br> <br>:)
i would like to know what type of sepper motor make and model you used and is your roter large enough to use on 1/4 steel if not what would you recumend ? <br>thank you <br>richard westerfield
Richard, this machine is not even close to being stiff enough to machine steel. If you want to machine steel you will need to use a proper milling machine such as a Sieg mill. There are a number of tutorials online on how to modify one for CNC use and this website (http://www.littlemachineshop.com/Info/minimill_compare.php) has a great breakdown of the different models sold by distributors.
Please say......... <br>What are the soft wares we have requried to operate Desktop CNC? <br>I Have Mach3(Downloaded from artsoft), AutoCAD,Kcam4(Downloaded from:http://www.kellyware.com/download/index.htm) and trail version of ArtCAM Express <br>I have doubt that,these softwares i have are not Genuine versions.....so These are having capable to operate Desktop CNC Machine or not? <br>Thank you........
Sir please suggest me...,cheaper and good working &quot;3 Nema 23 stepper motor 287oz-in cnc kit' from ebay
Please help me...... <br>sir.....i want to buy 3 Nema23 stepper motor 287oz-in cnc kit from ebay with cost of 132USD....ie china manufactered on through this link <br>http://www.ebay.com/itm/3-Axis-CNC-Kit-Nema-23-Stepper-Motor-287oz-in-3-Axis-Driver-Board-/140903100382?pt=LH_DefaultDomain_0&amp;hash=item20ce7aafde <br>I have doubt that it will work or not ? <br>It is suitable or not to our woodcutting Desktop CNC Machine?
Please keep on posting about This topic. I want to know more details about it. Anyway, I have read some of posts in your blog here. And all of them are very informative. Thanks for sharing. <br><a href="http://www.routercenter.com/" rel="nofollow">CNC Routers</a>
I was very encouraged to find this site. I wanted to thank you for this special read. I definitely savored every little bit of it and I have you bookmarked to check out new stuff you post. <br><a href="http://www.routercenter.com/" rel="nofollow">Used CNC Router</a>
+1 for Shigley's!! That's my bible.
you are too good man. can i use stepper motor with 80 oz in( 0.6 Nm) .will it work or not. <br>thks
You jump so quickly from hardware to software. Could you give more information how you work to load your designs to the machine. Also which motor drivers do u use? <br>Thank you so much
The Instructable was meant to focus on the hardware as software could vary depending on personal preference. In general I used Rhino 3D for the CAD work, exported as an STL which was loaded into CAMBAM. From there I generated G-code which was read by Mach3 and sent to the Hobby CNC driver board. Let me know if you need any more information.
Thank you for this instructable! I'm planing on building a similar one with some modifications on the Z axle to have a little bit more depth and I will be using a dremel 4000 as the cutting unit. you mentioned metric units...do you, by any chance, have the metric drawings for this? I am converting everything, but I then have to match it with commercial sizes and if had already done that... ;) <br> <br>another question...have you tried to cut either copper or aluminium with this machine? do you recoon it is stable enough for that? <br> <br>once again, thank you for sharing this ;)
It shouldn't have any troubles cutting aluminium using a dremel as long as you get a high quality double fluted, spiral, carbide end mill. I have quickly found that the cheap HSS cutter I have are limiting the machine's performance. As for metric drawings all I have are the imperial ones. As long as everything is sized as the closest metric alternative it should all work out with only a few holes needing to be re-bored larger.
that's what I've been doing ;) maybe i'll just cut all the parts in imperial sizes and make all the holes in metric size because it's easier to match with screws and nuts ;)
I want to built a 50&quot;x50&quot;x@5&quot; high routing capacity,what is yiou recommendation regarding the electronic and motor,i built several composit airplanes 4 passenger and i am designing a twin with Mazda rotary rx-8 engine. <br>First i get quote from several place with a big CNC router and they came up about$11000 to do the fuslage half mould from polystyrene. <br>This is why i started to look building my own from aluminum rectangular structure. <br>i do design with Rheno and any recommendation can be appreciated,my experience in router is very limited but i am learning very fast and i dont see any <br>problem of building the structure
The motors will depend on the weight of the gantry. Cutting polystyrene won't give much resistance at all so as long as the motors can move the machine it will be able to cut. The folks over at gecko drives have a good write up on how to estimate the size motors required (http://www.geckodrive.com/support/choosing-a-drive.html).
I was going to build this over the summer with my father, he used to sell CNC machines and he has always wanted to own one. We were wondering if this CNC Control Board would work with your instructable. <br>( http://www.ebay.co.uk/itm/CNC-Kit-3-Axis-Stepper-Motor-Driver-Nema17-12V10A-220V-/270900965305?pt=UK_BOI_Industrial_Automation_Control_ET&amp;hash=item3f12f4afb9 )
The only issue I see with the board is the 62 oz-in steppers. The motors I used are 130 oz-in and I have never noticed them stalling or loosing steps but compared to other builds I have seen, they are on the small side. The axes have a little resistance to overcome but not enough that I wouldn't expect those motors to be able to move the machine so the question is how much torque is left over to do the cutting. If you want to cut platic and wood I don't think it would work but if you're interested in cutting foam and milling PCB's I reckon you could get away with it. <br> <br>On another note, it is the first time I've seen a diver board being run off of a switch mode power supply without a few hefty caps to smooth things out. I'm not terribly knowledgeable on the electronics side of things but I would imagine that performance would be reduced compared to that if it was run on a beefier linear supply.
After some correspondence with them I was reccomended this model board. This board has 170 oz-in Stepper Motors. Do you think I would run into any problems with a higher oz-in? <br> <br>http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&amp;isIU=1&amp;item=261029020897#ht_8120wt_946
170 oz-in will work well. If I were to do it over I would get steppers in the 150-200 range.
After looking through your BOM, I noticed you bought CamBam and MACH3, why did you feel th need to get CamBam also, was MACH3 not capable enough?
There are four steps to getting something made on a CNC machine: <br> <br>1) CAD software. This is used to draw a 2D or 3D part to represent the desired geometry with lines or surfaces. <br>2) CAM software. I use CAMBAM. This takes the geometry from step 1 and figures out what tool movements are needed to cut it out. These movements are detailed using G-code which only gives a start and end point and states whether they should be joined with a straight line or an arc and what speed to go in between them. <br>3) Machine controller. I use Mach3. This takes the start and end points from G-code and figures out how to turn the motors to make the cutting tool follow a straight line, move at the right speed and accelerate and decelerate as required. This information is output as step and direction signals for each motor. <br>4) Drive board. This converts 5V step and direction signals into current through the motor&acirc;€™s armature making the motor move and by the right amount. <br> <br>Some of these steps can be combined. For cutting pockets and drill patterns I do step 1 within CAMBAM. Mach3 also comes with a few wizards which can specify pockets and drill patterns and achieve steps 1-3 all in Mach3. To achieve the full potential of the machine to cut 3-d surfaces I required the full Rhino-Cambam-mach3 combination. This is an add-on feature to the software and not its main purpose of machine controller. Artsoft also has a freeware program called Lazycam to do basic cad/cam work which is no longer supported but I have not tried it. The Mach3 documentation is quite good and will give you an understanding of what you can do with the wizards alone (http://www.machsupport.com/documentation.php). The machine is not tied to any particular software/hardware. There are many options for each step and any could be used, some free, some affordable, and some tens of thousands of dollars for use on 6 axis machines. <br>
Okay, I will check those programs out, I think I saw a blurb about them on the Mach3 site. My father used to sell heavy duty CNC machines in the 80s. The ones he sold used to go from $150,000-$1,500,000.
Thanks for your instructable. It's very good.

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