4th Axis Build Help

Glad I took the time to read DMS post. I was just about to pull out the numbers but he did the work for me.
Chris

MANY people say 6061 machines "gummy". I agree.
7075 machines like a fine wine.........Sweet!
 
All from Wiki:
T6 temper 6061 has an ultimate tensile strength of at least 42,000 psi (300 MPa) and yield strength of at least 35,000 psi (241 MPa).
T651 temper 7075 has an ultimate tensile strength of at least 67,000–78,000 psi (462–538 MPa) and yield strength of 54,000–67,000 psi (372–462 MPa).

Just wanted to add a source for these numbers.
Depending on T factors they can change drastically.
T4 temper 6061 has an ultimate tensile strength of at least 30,000 psi (207 MPa) and yield strength of at least 16,000 psi (110 MPa).
Mild steel (A36) runs around 400 to 550 MPa tensile and yield strength around 250 MPa.

If the 6061 will get the job done, then it will get the job done.
Chris
 
Here is a page of stats of various aluminum alloys



Have you chosen bearings? Have you figured out how you are going to pre-load the bearings?


I have chosen 32306 Tapered Roller Bearings. The seals are Timken 473448. I will pre-load by tightening a 3/4" nut on the shaft.

This is really good info, thanks.

Wow...$162.20...I don't know if it's worth it.

Jim
 
Tapered rollers should do well. Make sure you post some pics of the build ;)
 
Tapered rollers should do well. Make sure you post some pics of the build ;)

I'm going to post pictures from before, during and after. It should be comical to watch someone who has no idea what they're doing actually construct something useful.

Jim
 
Somehow, I thought this board would be a lot more active. Is it the time of year? Is the hobby dying? Is it that my topic isn't interesting? Is it an after-effect of censorship? What gives? I was hoping for a lot more feedback before I start making chips.
 
Kinda seems like we are waiting for you... Give us something to go on, I am very interested to see what you come up with! If you want more feedback, post a drawing, schematic, bar napkin sketch, etc. I will be happy to look at it and try to find problems!

Hell, put up a photo of a big block of aluminum on your mill, and you'll have people drooling. (Just me? Ok...)

Or just dive in and make some chips! Sounds like you have it all worked out, so go for it! And let us know if it worked! Or not! If it doesn't work, you didn't waste the time, or money, you just gained that much experience!

-Cody
 
Yeah, didn't mean to leave you hanging, but it sounded like most of your questions were answered (material, bearing fit..). I agree Codered, lets see that big old block of aluminum :drool:

So, how far have you gotten on the design? If you haven't already done so, I would draw it out on paper or in cad just to make sure you have everything accounted for. The other thing to think about is the order of operations (what order you are going to machine each feature in). I have found that to be one of the biggest difference between someone with experience, and someone just starting out, and it makes a big difference. Specifically, you want to re-clamp your work piece the fewest number of times as possible. If you do re-clamp, you want to work to an accurate reference. For example, on that big block of yours, make one surface as flat as you can, then measure everything from there, and make sure that surface is one against the table of your mill, or against your fixed vice jaw. I would also recommend squaring up your stock, and then marking out all your dimensions before you start. It's very easy to miscount cranks of the handle, and drill a hole in the wrong place; marking out lets you see if you are "on" or "off".

I had assumed that you were off working, if you have other questions, or are stuck, just ask, people are always willing to throw in their $0.02.

Not sure if this helps, but here is a link to some pictures of a dividing head I built when I was first starting out. The body is 2x2x2"

https://picasaweb.google.com/113058612034694188913/DividingHead?authuser=0&feat=directlink
 
Well, being the idiot that I am, I didn't realize it was my turn. I do apologize - I am new at this. I have begun and will post drawings and progress. Again, I'm sorry for not understanding the 'process'.

Jim

- - - Updated - - -

Here is a hint:

4th.JPG

This is my design that I created in Excel. Please bear with me.

4th.JPG
 
Looks pretty solid. What are you planning on doing for the spindle (construct, purchase)?

Not sure if you have seen this, but it's a 4th axis along similar lines. The guy integrated a brake into the assembly to help when doing heavy cuts

[video=youtube_share;b2-Kdud7eiA]http://youtu.be/b2-Kdud7eiA[/video]
 
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