Cutting gothic style post top

[cbradshaw]

Can anyone tell me how I would go about programming a gothic style post top. I want to cut this on a 4 x 4 cedar post.

Thanks

[Brady Watson]

Pictures speak a thousand words...Post an example.

-B

[cbradshaw]

Brady,

I am attaching a picture of one made out of pvc but I wnat to machine it on the top my my 4 x4 cedar post
8319

[Brady Watson]

How are you going to cut it - Multi-sided machining using a 3 axis tool or all the way around with the indexer?

-B

[cbradshaw]

Brady,
I will have to cut each side and flip it over. I don't have an indexer.

Carroll

[myxpykalix]

Carroll,

You could do this real simply on your Legacy with a template. if you can get a picture of the sample 90 degress to the camera and copy the angle like my example you could make your template in partwizard and cut it out on the bot.

Then take your template and a 1/2" endmill use the template to cut the shape cutting from the side as shown in the pic.
Then just take a 1" or 2" corebox bit and run it front to back across the top to create your cove on the bottom.

8320

[myxpykalix]

for that matter you could use the profile to create a polyline of the profile, use it to create a toolpath with a 1/2" endmill that is as deep as your part is thick (2"?) and create a jig that would hold your part above the table slightly above the surface and let the area to be cut stick out.

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[cbradshaw]

Jack,

The problem with doing it on the legacy is that the post is 7 feet long and my legacy is only 6

I can create the profile but I guess I don't know how to tell the bot to cut that profile the width of the 4 x 4.

[myxpykalix]

couple questions:

Is all you are wanting to do is create the profile you show on the top of the 4X4 on all sides?

Do you have a side view (90 degree) picture of the profile you want to create? Send it to me and let me see if i can set it up for you.

[myxpykalix]

Couple other questions:

How big is your table?
That is the longest endmill you have?

I have a couple of ideas cooking.

[cbradshaw]

My table is 8 foot. If I can figure out hot wo cut the profile I will just turn the part. I already do that for anothe style post I make.

Thanks for trying to help me!

[bill.young]

Hi Carroll,

If you don't have a bit that's long enough to cut from the side you could try running your profile toolpath through the Extruder Virtual Tool and cut it from the top with a ballnose bit. It will take longer to cut than cutting it from the side, and might require a little cleanup because it's a raster pattern, but it's another option.

Bill

[gundog]

If you can draw the profile mirror it and cut one side both profiles 1/2 the post depth then flip the part and cut the other half. A little sanding to clean up the seam.
Mike

[mikeacg]

I know we all love to use our ShopBots for everything we do but wouldn't it be faster to just make a pattern to trace the profile on the posts and cut them on a band saw? How many do you have to make, Carroll?

Mike

[cbradshaw]

Mike,

I do mailbox replacements and this is one of the mailbox post styles that I have to make. I have been buying this one from a competitor and it takes about 1o days to get it beside the fact he is 25 miles away.

The bandsaw will work and I just bought a new Rikon bandsaw and love it. I thought it would be too difficult to manuever the 7 foot post. Maybe I will give it a try.

Thanks

[mikeacg]

Carroll,

Have you considered making your caps a modular component like the pvc one you pictured? That would make it easier to maneuver on the band saw and would also give you the option of offering more styles of caps. You could make a fixture to cut the pocket on your Bot.

Mike

[erik_f]

Carroll,
Here is the file I sent you simulated cut one half in aspire. The same thing could be done on PW Cut 3d

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[dray]

you can bandsaw that in about 10 mins.

[erik_f]

I don't have a bandsaw! Ha! Besides wouldn't be more fun to watch your CNC cut a 3d file for a couple hours.

[Gary Campbell]

Carroll...
If you cant cut these with a long bit using a 2.5D multiple pass and clearance strategy,you might want to make a jig for the drill press to cut the circular recess 4 times with a forstner bit and then switch over to the bandsaw using an arc jig and trim the tops to a point. This should keep the machining costs somewhere near what they should be.

As much fun as it used to be to watch the machine run, I prefer not to have hours of machining into a $50 part.
Gary

[erik_f]

Good thing I sell cigars for a living

[dray]

Ahh then have fun! I am no good at 3d designing or I would help.

[erik_f]

I'm not very good at it either, that's why I did it. Just for practice. I'm pretty sure this could be done with a 1/2" ball nose pretty quickly...not as fast as a band saw...but you could set up a bunch on a board and walk away.

[cbradshaw]

Update,

I used everyone's advice. I cut out a arc cutting jig using the shopbot, used the bot to cut the 2 inch cove and then band sawed the rest.

Thanks, for everyones help.

I do have one more style to cut and it will be a 5 step process unless I can program the bot to cut it. I have a 3d model but I am not sure how to approach it.

Carroll

[Brady Watson]

PartWorks3D or Cut3D - either 2-sided or 4-sided milling.

-B

[cbradshaw]

Gents,

I have another post top that I need to cut. I have a model but do not have enough experience cutting 3d files to make the toolpath. Can someone help me with this?

I want to be able to cut each side and then flip the post to cut the other side.

I tried to upload the model but I get an error saying the file is too big.

[cutitout]

I have Cut3D if you would like for me to look at it? what type of file is the model?

[Brady Watson]

Cut3D is only $299 - which could easily be absorbed by just a few jobs.

-B

[cbradshaw]

I have a stl and a dxf file of it