NC Router build

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9/13/2018 8:39 AM

We're rolling.
Computer and software are set up. At least as much as I can without a machine to test it on.
Some cast aluminum plate was donated to the project by a a customer. I will be using it for just about everything except the tube frame. This material is much more stable than 6061 T6. I just have to saw it close and machine to final dimensions.
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A quick hit with random orbital cleans off the oxidation.

Some of the linear bearings are here.
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Ball screws hopefully here in a couple of weeks.


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9/20/2018 2:19 PM

Progress. Most of the pieces cut. Y and Z axis plates are done.


Cutting outside dimensions.
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Counterbore for Z axis. Photo

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9/27/2018 9:01 AM

Testing the Z axis

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9/30/2018 5:02 PM

Base machine is done. I still have to design the work table. I would love a T slot table but it's really expensive. I only have about $800 in it now and the table is like $400.
Everything seems to work. I get some odd noises from the steppers from time to time.

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9/30/2018 6:22 PM

Looks great so far ,nice work . What material do you have in mind for the work surface ? They sell these sections of T slot track that you could possibly use on your working surface. I know the wood working guys recess them on table tops.
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9/30/2018 7:06 PM

Looking forward to the progress on this build. Thanks for sharing. Are you going to replace the router motor with a cartridge spindle?

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10/1/2018 5:07 AM

Sprew, if this was going to be a production machine I would go with a water cooled spindle but it's more of a hobby machine at this point. I will be getting a speed controller for it though because I have to be able to drill.

Mr.X, some machines have an MDF table with a pattern of threaded holes for dogs. That's easy to do but not that versatile. I have seen the t slot rails too and some guys use toilet bolts with them. I have some research to do.

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10/1/2018 9:03 PM

Borg - The point I was trying to make (subtly, if I understand your configuration) is that the nose of your spindle should be below the bottom of your Z axis ball screw bearing even when your Z is max positive.
I think that once you get a work surface installed you will have more Z travel than you have clearance.
The spacing of the ways looks good.

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10/2/2018 4:36 AM

Sprew wrote:

Borg - The point I was trying to make (subtly, if I understand your configuration) is that the nose of your spindle should be ...more

You are right, the spindle is too high and I plan on modifying that but it's partly that way because I will be mounting a drill chuck to the spindle which will add 2 to 3 inches plus the drill bit so I need the additional Z+ to accommodate that but I did over do it. For plain routing though I need to drop the router down about 2 inches. I will probably just add another plate at first but eventually I will probably make another Z axis plate.

So far I'm happy with the rigidity of the design. The rapid speed is ridiculous. I have it at 5 in/sec which is plenty and it will go much faster but why? I'm working out some issues with accuracy on the Y axis. It misses it's home position by .005" to .010". I think I narrowed it down to one of the cheap drivers but I have to try massaging the step rates and such before I toss it.

Thanks for the input.

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10/11/2018 7:19 AM

Update. Did the modifications to Z axis to give more clearance. Went to the DeWalt router with a separate speed control (not shown). I tried the Harbor Freight router first partly because it came with 3/8" collet which most of the others don't offer. What a POS. I ran it for 3 minutes and screws started vibrating out all over the machine. You have to be very selective on what you get from HF.

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10/11/2018 8:44 AM

Not really sure how many routers i have,five ish ,some in tables for this and that,but my favorite is the first.

It's a 75ish model made by craftsman. The switch burns up so I just wire it straight.
Full wile E coyote but it just fits the hand and lite.

What are you cutting? Metal or wood Ivan?

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10/11/2018 11:09 AM

hillbilly wrote:

Not really sure how many routers i have,five ish ,some in tables for this and that,but my favorite is the first.

It's a 75ish ...more

Just wood. I could probably take some really light cuts on aluminum but I don't think I will. I have access to a real CNC machine for that. Besides, I would end up getting coolant all over my nice dry work surface.

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11/5/2018 6:58 PM

Update.
Machine has been done for a few weeks. Doing some video for a YouTube thing.

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11/12/2018 10:53 PM

Borg
Did you see this?

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11/13/2018 7:02 AM

I wish I could have seen more of what he was calling a router. I saw engine lathes and milling machines but only a short view of a router spindle, cutting aluminum.

I do have to say that I was surprised that he was drilling into steel without center drilling first. So I wasn't surprised that he broke a drill. Maybe I'm anal about center drilling and other metal machinists might disagree but I always center drill when using jobbers length bits. Especially small ones.

Well done video though. So far, mine is very crude and moving along at a snails pace.

Thanks for the post, it was interesting. I may have to learn a little about cnc lathes. It would not be hard to set up a spindle on my router except it wouldn't be for cutting metal.

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11/13/2018 11:23 AM

Pretty cool. You'll be cranking out carved Les Pauls in no time!

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11/13/2018 6:00 PM

Foghorn wrote:

Pretty cool. You'll be cranking out carved Les Pauls in no time!

I'm doing carves now. Not a Les Paul though. They have more challenges other than just carving.
This is one is progress. 2 more coats of lacquer and it goes on the hook for a month or so. It may be hard to see the carve in the pic.


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11/13/2018 7:18 PM

I don't know if I'm spewing a bunch of stuff you already know but I'll throw a few things in anyway. A vacuum table and spoiler board is the way to go with wood working. You don't want to have to program around clamps and fixtures. Even with 5 head high production machines we still used spoil boards.
Can you change your spindle speed? Depending on what bit you are using and spindle speed should determine your travel speed. Different bits will indicate what they are to be run at and others you can tell by the tool marks. Not all bits in a router will leave tool marks that you can read but you shouldn't have more than 1/16" spaced tooling marks on your work piece if you are traveling at the correct speed for machine and bit as well as the type of wood. On the slow side, you shouldn't have tool marks less than 1/32" or chances are your bit is running hot. Type of wood matters because you are not going to mill Cherry, Oak, Poplar and Mahogany at the same speed. Especially in turns and corner cuts.

I'm just thinking that if you can't change your spindle speed or know where it is at, and change your travel speed for turns that 5" per second is screaming fast for this set up.

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11/14/2018 6:04 AM

I'm basically a novice at this stuff. I just learned g code 6 months ago. I end up teaching myself stuff all the time by scrapping out wood. I use spoilboards for only a few things. I intend to make the same things many times. For that I make tooling which has it's own machine coordinates and position on the table.
I can adjust the spindle speed but I only use it for drilling and it doesn't work all that well.
I just use the router at full speed for most cuts. For a 1/2" carbide straight flute bit I cut at about 15 ipm at 1/4" depth. For very light shallow cuts it's more like 40 to 60 imp. I am limited by the router itself which is rated at 1 3/4 hp. That's a bullshit rating though. It's an 11 amp motor at 24,000 rpm's. I don't have the available power in my garage for a real spindle but I think the machine can handle more.
I'm not sure what you mean by tooling marks. Can you explain it?

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11/14/2018 7:57 AM

I googled and got this information from this site. http://www.tinkerandfutz.com/a-guide-to-cnc-bits/

Balance your need for speed with edge finish

Generally speaking, the bit design you choose will be designed to cut fast or cut smooth. Think of the difference between a chainsaw (fast) and a hand saw with fine teeth like a fret saw (smooth). If you need to cut a large amount of material in a hurry in a high volume production environment you’ll go for an aggressive bit that can be pushed through your material quickly. If you are making furniture and you’d rather not spend a day sanding a ton of tool marks off your nice hardwood, you’ll want to choose a bout that is made to leave a smooth finish. The more flutes (cutting edges) that a bit has, the finer the cut. A single flute bit will be very aggressive and leave a rougher edge than a 4 flute bit will. On the other hand, you can push a single flute bit through your material much faster than a 4 flute bit. This is because making one cut per rotation allows for a more aggressive feed speed than a bit that makes 2, 3, or 4 cuts. Chip clearance is also improved with fewer flutes meaning faster cuts.

(My comment)
I think it had some good info that might give you a better idea of what I was talking about. What I am saying about the tool marks are that some bits leave straight lines that you really can't read but usually they have a speed rating to tell you what to run them at. Others will leave tool marks much like a planer or molder. Its been so long since I have been around it that I forget the different types of bits. But what ever bit you use or even what type of bit it should be cutting at a rate of no more than every 1/8" and no less than 1/32" to be running at optimal speed. This is for the durability of the tooling as well as the finish on the product you are milling. I'll look and see if I can find any documentation on it or if I have any old hand books that explain it more. Basically you can go fast and rough or smooth and slow by bit design. No matter which you choose, your bit still should be cutting in the 1/8" and 1/32" range (spindle speed and travel rate). But for woods like Cherry for instance chips very easily, you need to slow it down in the curves. A few curves is fine but if you have a lot of curves, you are heating up your bit. Cherry as well gets burn marks real easy so if you have a lot of curves with Cherry it will take a lot of thought and compromise to get the final product you are wanting to achieve.

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