View Full Version : OK goin in... full speed!


boosted
01-18-2007, 05:16 PM
Ok well I decided I am done lookin and will go ahead and start a project.
I only really need a 30X30X10 table but after looking around and pricing the simple parts, I decided to go a bit bigger...
36"X72"X12" which should net me close to a 30"X65"X10" usable area.
I was going to go all out and do aluminum plates for the frame, but then thought why?
So I rethought a few things and decided to go 1"X2" T-Slot extrusion. I will be adding a cross brace every 24" to add rigidity and reduce and kind of lateral flex.
After reading several build ups I decided on the acme 1/2"X10 threaded rod, but decided on the 4130 (bend that I dare ya!) with the black oxide finish to prevent any chance of rust.
I am also wondering what people have used to support this? I am assuming they have a certain amount of the threads milled off and use a thrust/tapper type bearing?

I was thinking about 3/4" 304 S/S for the guide rods, any thoughts? yeah neah? Yes on the massive 6' run I will run several supports.

I will mainly be running 1/4" 6160 aluminum plate but on occasion run 1/2.
Or anything that any hobby race team/person brings me.

I have the general idea of what I want done and how to do it, but I will be the first to admit I do not know everything and will gladly take suggestions and help anyone will give.

yukonho
01-18-2007, 05:30 PM
Welcome!
In your post you said you will be running 1/2 and 1/4" aluminum, do you mean this is what you will be cutting? If so, a router is not the right machine for you, you need a mill.
I am sure you have heard it before, but I am encouraging you to go for a smallish machine to start. Too much flex will make your machine un-useable. Be sure to get plenty of opinion and think everything through several times.
Good luck!
Colin

boosted
01-18-2007, 05:36 PM
Welcome!
In your post you said you will be running 1/2 and 1/4" aluminum, do you mean this is what you will be cutting? If so, a router is not the right machine for you, you need a mill.
I am sure you have heard it before, but I am encouraging you to go for a smallish machine to start. Too much flex will make your machine un-useable. Be sure to get plenty of opinion and think everything through several times.
Good luck!
Colin
If I had the cash I would get a mill but I don't, so I'm having to do this. The same goes for the smallish machine.
For the most part it will be cutting simple shapes and a few picture engravings.
I also plan on having the program run depth in stages, I:E; deal with things 1/8" at a time. Yeah it till take longer to run parts, but it will immensely reduce stress on the machine framework and should produce better results.

Yes after I make some cash with this machine I plan on getting a mill and turning this to a light(er) duty machine.

Also the 6160 is a light aluminum, and the 1/2 will be few and far between. I figured a good 1.5HP router should make light work of it.

GaryCorlew
01-18-2007, 05:39 PM
What are you planning on running on the guide rods? If its linear bearings, the stainless will not work, you have to have hardened steel or else the bearings will dig in.

boosted
01-18-2007, 05:41 PM
What are you planning on running on the guide rods? If its linear bearings, the stainless will not work, you have to have hardened steel or else the bearings will dig in.
Nice to know cause I was planning on using linear bearings...

thkoutsidthebox
01-18-2007, 05:44 PM
Hey and welcome again! :)

Just wanted to say good luck with your build and dont forget photos! :) Videos are also good after its finished. ;)

boosted
01-18-2007, 06:53 PM
well hardened is up there in price.
Will 41L40 be fine? I think it will be but want to ask...

yukonho
01-18-2007, 09:28 PM
You can not use anything but hardened rod for linear bearings, sorry. You can do a search on it and read up for info, or just trust me that people have tried it and the balls always dig into the shaft on anything but hardened shaft.
For what it's worth, your machine is far too big to be thinking of milling aluminum like you are talking about. Cuts will take forever and the machine will flex a lot. Machining marks will be ugly and chatter will be everywhere. A CNC mill like the X3 can be had for a couple grand now and will do the job you want it for. Check out Syil, they have ads here on cnczone.
I am not trying to pop your bubble here, but I think it is important that you hear this so you dont make a big mistake.
colin

boosted
01-18-2007, 11:21 PM
You can not use anything but hardened rod for linear bearings, sorry. You can do a search on it and read up for info, or just trust me that people have tried it and the balls always dig into the shaft on anything but hardened shaft.
For what it's worth, your machine is far too big to be thinking of milling aluminum like you are talking about. Cuts will take forever and the machine will flex a lot. Machining marks will be ugly and chatter will be everywhere. A CNC mill like the X3 can be had for a couple grand now and will do the job you want it for. Check out Syil, they have ads here on cnczone.
I am not trying to pop your bubble here, but I think it is important that you hear this so you dont make a big mistake.
colin

Ok, I broke out the pens, pencils and paper and laid out my own design. I will still be using the T slot, but for pure material mounting/retaining only.

All the frame parts will be 3/4" aluminum.
The uprights will be 35 cm long at the base and semi tapered at the top. They will also have 2 cross supports connecting them, the rear one will be 20 cm tall with a retaining screw every 2 cm. The bottom brace will be 14 cm with a retaining screw every 2 cm. The Z axis will employ the use of two (one per side) double sized linear bearings. Everything else will use single sized, 4 per axis (2 per rod).

I am not sure what I was looking at before on mcmastercarr.com but it certainly was not what I thought it was. The 3/4" hardened rods and 24" supports will only be around 180ish. Again I am keeping the size mentioned before, hence why I am adding the supports 4" long centered every 20".

I would post the actual design but I have not gotten used to autocad yet and translating all those paper dimensions can get confusing for readers.

cncboss6
01-20-2007, 05:26 PM
Hello, use thomson shafting which is also called c-60. It is 60 rockwell, ground and polished. That is what the factories use with linear bearings. Pat

boosted
01-20-2007, 08:41 PM
Hello, use thomson shafting which is also called c-60. It is 60 rockwell, ground and polished. That is what the factories use with linear bearings. Pat

I am getting the mcmastercarr, hardened precision shafts.

cncboss6
01-20-2007, 09:08 PM
Chances are, it is about the same as Thomson shafting. I was just trying to held, Iam a toolmaker, and do know alittle about steel. Pat

boosted
01-21-2007, 03:41 PM
Chances are, it is about the same as Thomson shafting. I was just trying to held, Iam a toolmaker, and do know alittle about steel. Pat

I checked out the details for them today.
Case hardened shafts, linear bearing purpose made. C60 exterior toughness.
Considering I am getting 2 each of the following 16", 36" and 60" for 160ish I am not complaining.