CNC project for beginner operators ( Horizontal twin cylinder)

[stevehuckss396]

Hey guy's!


I have been working 6 days a week and have had very little time for projects. I cannot find more than an hour
here or there so I decided rather than do nothing, I'm going to make a few simple things here and there.

Jimmy, One of the guy's in my club wanted me to redesign Mr. Graham's HOSC engine into a twin cylinder. I liked
it so much that I blew it up to double size and decided to build it out of Corian countertop material. Jimmy
stops in at a cabinet shop and one of the workers there gives him the sink cutouts and scraps for free. Others
have made custom pens and YoYo's and other things out of the corian to give back as a thank you for letting
us have the scraps. I'm going to build this air engine to give back to the corian guy to thank him for the
pieces I have gotten over the years. If you have seen the base plates for the Peewee and Demon and the spark
plug insulators, they were all made from this persons generosity.

My plan is to make a part a week. With Mr. Graham's permission I will make the plans and the Gcode available
to anyone who wants to build one. The plans and Gcode will be attached to the post. I will try to get the post
up every Sunday. The plans will only contain the information required to finish the part so this will be a CNC
only thing. The CNC parts will be the base, standards, flywheel, and cylinders. The manually made pieces will
be the pistons, crankshaft parts, and finishing the CNC'd parts.

CAUTION: The Gcode was written to be used on corian. This material is like plastic so the speeds, feeds, and depth
of cut may be way to aggressive for aluminum.

This will not be as easy as it seems. Corian has no standard thickness. I have measured pieces from .445 to .485
depending on the type and color. As the pieces are made and the project moves forward, there will be some
adjustments that have to be made. If you are the kind of person who can run into the unexpected and just roll
with it, this is your project.

First I found the center (X0,Y0) of a 7 X 5 inch piece. The top surface will be Z0 for all tools. You need to
setup this way because I wrote the code to cut .525 deep to make sure the thickness of any piece will work. You
can also stack 2 pieces on the table to protect your table when the cutter goes thru.

The holes are center drilled, and drilled with a #37 drill bit and a 1/4 inch drill bit.

Then a 1/8 inch endmill was used to cut out enough of the part to allow the next step. I know you are thinking
that a larger endmill could have been used but my mill has a small spindle motor and gets real hot with the
larger bits. I used the smaller bit and cut at 60 inches a minute and it goes fast.

Don't worry about the funny looking cut down the middle. That was operator error and not the Gcode.

A 1/16 inch radius cutting endmill with a 1/4 inch tip was used to clean up the edge. If you don't have
this cutter and don't want to buy one, you could just leave the 1/8 inch endmill in and press cycle
start. The mill will go thru all the moves and when prompted for the 1/8 endmill again, it is already in
so cycle start again and you can continue having skipped the radius step.

Then the 1/8 inch mill was loaded and the piece was cut out.

The corian is brittle so cutting the tabs with a plier caused the piece to chip. Cutting it out with a band
saw might take a bit longer but will avoid damage. I haven't figured out exactly how I'm going to feed the
air to it so that won't be addressed at this time.

View attachment Standard.tap

View attachment Standards.pdf

 

[chrispare]

Geez if this is what you do in an hour,,
nice work this is going to be a fun one.

Thanks for your spare time work and sharing with the rest of us!

 

[stevehuckss396]

Geez if this is what you do in an hour,,
nice work this is going to be a fun one.

Thanks for your spare time work and sharing with the rest of us!

I draw and do the Gcode in the house while I'm watching the tube. I think it took just over an hour to make 3 of these pieces.

That's something I forgot to mension about the CNC. If you go to all the trouble to setup, make 2 or more of what you need if material allows. The first one might take 30 minutes but the next 3 might take another 30 minutes. If you make a boo boo, you already have another.

 

[Path]

This is going to be fun to watch and build.


Thanks,


Pat

 

[steamer]

Bubba , this is a damn fine idea!

You sir are a genius! :bow: :bow:

Dave

 

[kjk]

This is a great idea. I'm just about to start learning cnc at a local maker's co-op. What software do you use Steve? I still have an opportunity to influence what software tools the co-op gets. I know we have some donated licenses from Solidworks and AutoCad, but no one has mentioned a CAM solution. The mill is a Tormach 1100.

 

[stevehuckss396]

Bubba , this is a damn fine idea!

Thanks Steamer!

To Path (who sounds like he might actually build one) and anybody who does make one, I encourage you to post your pix of finished parts in this thread along with mine. Post the pix to show your success but also show the failed attempts so we can learn from them along with you. There seems to be alot of new CNC mill owners here lately so lets all help each other out.

The idea of this thread is to concentrate on one piece at a time. Show pix of how you did and help each other out. Then try to apply what we learn to the next piece and see if that one comes out better than the last. I'm no CNC expert so I hoping to learn some tricks here also. I'm going to use some simple fixtures to make the cylinders and flywheel. They will be made from corian also and only need to last long enough to make a dozen pieces. I'll show how I go about doing things but if you have an idea of a different or better way, pipe up and show it.

I could post some pix of the finished parts and blast thru the build but I see an opportunity here to share and gain something here so. . . .

Anybody going to try this thing?

 

[Mosey]

Which handle is the CNC one? I only have 3 handles on my machine. ( I'm jealous).

 

[stevehuckss396]

Which handle is the CNC one? I only have 3 handles on my machine. ( I'm jealous).

You would have to ask GBritnell on that one. He seems to have found it.

 

[stevehuckss396]

Finished the first pieces today. After getting the waste cut off I had 2 pairs that didn't seem to match. It is
extremely important that the two crankshaft holes be the same height off the base. If you have any reason
to believe that the two pieces don't match, put a couple of 1/4 inch drill bits into the 2 holes and take a
skim cut to get them perfect.

I made a few extra pieces so i needed a way to setup the pieces quickly for drilling. Using a scrap piece of
Corian I milled the entire piece flat and then cut a slot 1/8 inch deep to use as a setup block.

Now I can but the piece into my stop and then push the piece up to the setup block that is sitting on the
vise jaws. Should get every piece into the same place and nice and flat to within a few .001's every time.

I drilled all the left sides and then switched to the rights. The piece is left overhanging the vise so I could
get my finger under the piece to press it into the under side of the setup block.

I chucked an 8-32 tap into my battery drill and ran threads into all the pieces. Then the holding tabs were
ground off and polished with sand paper. I try to leave my tabs at high spots or corners because it makes it
easier to clean them up after.

Next piece will be the base a week from tomorrow. Until then i have alot of tabs to grind and polish.

 

[Tin Falcon]

Looks great Steve I am trying to talk myself into this build should be relatively easy yo do as you are doing the R&D and blazing the trail thanks for sharing.
I do want to reminds folks of safety. the MSDS sheets for Corian are a bit long (7 pages)and confusing here if anyone wants to read it.
http://www2.dupont.com/Surfaces_Commercial/en_US/assets/downloads/pdfs/COR001_CORIAN_MSDS.pdf
the basics
1) collect dust at the machine.
2) clean up dust in the shop.
3) do not breath dust.
I have done a fair amount of Corian work here are my methods
Keep the shop vac hand and collet chips as produced if possible. Collects dust and keeps the tool cool.if the tool gets hot the colors turn milky .
vac up around the machine after the parts are made.
wear a dust mask if the stuff is flying.
wet sand Corian it keeps the dust down and he surface cool .
Tin

 

[Tin Falcon]

this may be a dumb questions Steve but it seems like you have a lot of extra material around the palr. How necessarily is the 5x 7 ? I know you have it up on blocks and need some clearance on the ends so your tool holder does not hit the clamps but why so much on the y is it needed for support. I have a bunch of Corianin 4 - 4 1/2 inch strips so am thinking of using that. May clamp to the table with a sacrifice piece under it.
tin

 

[stevehuckss396]

this may be a dub questions Steve but it seems like you have a lot of extra material around the par. How necessarily is the 5x 7 I know you have it up on blocks and need some clearance on the ends so your tool holder does not hit the clamps but why so much on the y is it needed for support. I have a bunch of corianin 4 - 4 1/2 inch strips so am thinking of using that. May clamp tot he table with a sacrifice piece under it.
tin

You could probibly go as slim as 3-1/2. Just want to make sure it stays together while the piece is getting cut. I just happened to have a 5 inch piece here.

4-1/2 would work well for the base also which is the next piece that will be made.

 

[steamboatmodel]

Which handle is the CNC one? I only have 3 handles on my machine. ( I'm jealous).

Its the one with $$$ on it. CNC is great, you can fill a scrap bin in no time, and come back later and refill it with identical parts.
Regards,
Gerald
Retired CNC Technician.

 

[stevehuckss396]

What software do you use Steve?The mill is a Tormach 1100.

Steve is using CAM BAM for the CAM I would expect Mach 3 for the CNC.
Tin

I use Alibre to design and create the DXF (2D) and STL (3D) files.
Sometimes I use AutoCAD to modify the DXF's
Then I use CamBam to create the Gcode
Mach3 runs the mill and if I ever get around to it, the lathe.

There is a free program called DeskEngrave that is good for creating and engraving text.

 

[Tin Falcon]

Mosey no need to be jealous CNC is just a different way of spending hobby time and money. It can be a faster way of making parts and open new possibilities. And it can reduce tooling needs. but it is a different learning curve. I big part of me wishes I waited and bought a second mil to turn to cnc. but all learning is good.
like anything else if the want to is there you can do it.
and like Gerald said you can scrap parts faster as well.
Tin

 

[stevehuckss396]

and like Gerald said you can scrap parts faster as well.

Another reason I thought this would be a good CNC start. Corian is cheap and sometimes free. If you make a bonehead move (and I have) you might have a shot at not breaking the tool. I plunged an endmill straight thru a 1/2 inch thick piece because I forgot to reset Z to zero after a tool change. The mill and tool were fine and no damage to anything but a piece of Corian.

Anybody besides Tin going to build?

Friday after work I'll post the base with the code and PDF drawing. I'll do a friday post every week so you will have the info for the weekend.

 

[Jeremy_BP]

I'll certainly give this a go when (if) I finish my CNC mill build.
Looks great so far!

 

[chrispare]

I am waiting on a chip for my board, once im back up I will give this a go as my first cnc project.

Its quite ironic, An alumn chip somehow found its way to the stepper chip pins and shorted it out.

 

[kvom]

A few comments and questions:

1) Any chance you can supply the CamBam files those of us that have the program?

2) I assume you set the tab height tall enough to account for the thinnest Corian you're likely to get. Otherwise the tabs could be quite fragile.

3) I recently acquired a quite large piece of Corian. I have been thinking of cutting some pieces up to use as fixture plates for milling metal parts. Any reasons not to try this? I assume I can cut it easily with a jigsaw.