Kb58's granite CNC router build

[kb58]

The spindle, mount, and VFD are stuck at FedEx in Memphis while our government determines what the import tariff will be.

I'm torn on the whole tariff issue. On the one hand, tariffs (may) serve to make a country reconsider their business practices. On the other hand, who does it directly impact the most? Answer: me, the buyer, and the factory I'm buying from. It's a stretch to say said factory's business will be so impacted by a US tariff as to induce the Chinese government to change their ways. I find it ironic that a tariff designed to punish China actually ends up punishing the end user the most instead of the originating government.

I get it; China's notorious for copying things made elsewhere, then undercutting their competition's prices, and the US wanting them to stop doing that. I completely agree that sending all our money to a foreign country hurts us as a nation. I think WalMart has done more to break our nation's manufacturing than any other, but I digress. The theory of the tariff is that by forcing the customer - me - to pay a lot more, it'll make me consider domestic sources... I did, and as far as I can tell, there aren't any US (non-ATC spindle) manufacturers!

The right solution is to apply tariffs only on competing foreign products, not on ones with zero domestic competition. The trouble is that's hard to do, so instead, the US took the easy way out: everyone pays a tariff even on stuff where there are no domestic options. Gee, thanks.

 

[kb58]

The spindle is still stuck in the US Customs system, saying that the shipper owes them additional information. The shipper says that they've supplied that information, twice. Called Customs and they said they'd send me a form to fill out - nothing happened. Called again, supplying the same information they requested the first time, and again, nothing happened. Good thing that I don't need this anytime soon.

Mental note to self: think twice about ordering something that goes through Customs.

 

[kb58]

Well that wasn't much fun...

FedEx sat on the Chinese shipment for weeks, then finally forwarded it to Customs. Customs directed me to an online 5106 form to fill out, which I did the same day. A week later, hearing nothing, I sent an email asking if they were waiting on me - nothing. Another week passed and I sent another email asking the same question. Again, nothing. This week, they just updated the delivery status to... "Sending back to shipper." WTF. No notice, no indication of why, it's just heading back to China. I have no idea what's going on. I let the shipper know immediately; he's been very helpful and cooperative throughout the entire situation, so I don't think there'll be any issue concerning a refund. Right now though, I don't know what to do about getting a spindle - at least through FedEx...

 

[kb58]

The manufacture convinced me to try one more time, this time with UPS. So far things appear to be going much smoother, with it having already cleared Customs today and I should get it tomorrow.

 

[kb58]

The spindle arrived on 29 December in great condition and oddly, sailed right through Customs without them contacting me... I don't get it. I have heard stories of people getting a big bill from Customs after the fact, so we'll see. The spindle is a real beast at around 42 lbs, and its mount, sheez! I also bought a variable frequency controller because they carried pre-configured units. I'm very pleased with Jianken, the manufacturer, and even though I have yet to run the spindle, highly recommend them. They certainly went above and beyond to get me the spindle. Once the replacement shower door is installed (currently stuck in-route due to weather), I'll at least temporarily wire up the spindle and verify operation. There aren't a lot of other parts needed to get on with construction. Collets are needed but that's way down the road.

The first thing is to figure out how to square and flatten the glued-together granite cross member. I still think the easiest way is to use my mill and a diamond surfacing disk. The idea is to keep the cutter wet, which eliminate dust, makes it last much longer, and cuts down on heat distortion, but requires protection of the mill from flying water and grit. Another way is to cut it dry, eliminating the flying water, but there's still the grit, which will get everwhere. A vacuum can maybe deal with that, but I guess the path forward will become clear once I'm there. Of course, maybe by some miracle, it's already flat... uh huh. Having a surface plate to work off of does make it much easier to check, regardless.

 

[kb58]

A heavy duty but beat-up stand came with the surface plate. While it's perfectly usable, I don't like it due to its near total wasted internal volume. Instead of modifying it, I "invested" in a portable work bench with proper drawers that was on sale. It was exactly the same height at the old stand, so it wasn't hard to slide the surface plate onto the new work bench. After looking at it a while though, I worried it was going to be too much weight once the surface plate, granite side plates, rails, granite gantry and spindle are added, for around 600 lbs. The picture you see here was after deciding that reinforcement was needed, and a triangular frame will be riveted inside the frame just below the butcher block top. I bought two steel rems for the job, both about 50" long, but I still have the nagging bad habit of cutting things too close, and didn't buy enough!

 

[kb58]

The router assembly is going to be pretty heavy (~350 kg) and the surface of the workbench seems marginal. Surface plates are supposed to be supported by three points 20-25% in from the edges, so a frame was fabricated to cross under all three points. It'll be welded together and riveted to the inside frame of the workbench, just under the top, then the butcher block top reinstalled. the wood could be left out but does look nice, though it'll be nearly covered by the surface plate.

 

[kb58]

The brace was partially welded, and finished welded in-place because return flanges on the frame prevented putting it into position as a complete assembly. Welding it while squeezing myself inside the workbench, sans drawers, inverted, with no head support was probably the toughest welding I've ever done. Anyway, it's done, riveted along the workbench's front and rear flanges, the wood cover was reinstalled, and the surface plate slide into position, again.

With that done, the original surface plate table/support needs to be gone. It'll either be put on Craigslist or put out on the curb with a "FREE" sign.

Getting the original table out of there frees up valuable floor space and makes it more pleasant to work in the garage. The next challenge is not so much drilling and attaching the granite end blocks onto the surface plate, but ensuring that the blocks end up at exactly the same height. In the video series I followed, the guy had a sweet little drill press that he could slide around on the surface plate with a diamond grinding wheel in it, sliding it back and forth to grind the tops down to a consistent height. I don't have one, and Bosch doesn't sell the model here, never mind not having the space to store it afterwards.

A few ways to end up with level tops might include:
- Placing the two granite end pieces on the mill, grinding them while keeping the grinding bit wet to cut down on wear and dust. The identical pieces would then be sat on some aluminum tooling plate placed under the surface plate. This seems like a bad idea overall due to the rock dust, grit, and water being thrown about.
- Bolting them on loosely and use a vertical caliper to ensure the tops are the same height, shimming them as necessary before bolting and epoxying them on.
- Bolting them on as-is, then shim the rails to level and square. I suspect I may have to do this regardless, so do I just embrace it as what needs doing regardless?

 

[kb58]

I think the best way to ensure that the granite side rails are the same height and in-plane is to use two small surface plates as references. Using 8" tall plates (when placed on-edge), and bars placed across the top, should create a plane parallel to the main surface plate. The side rails will be placed roughly in position, and shimmed up until they butt against the bars, then glued and tightened to the main surface plate. If necessary, sand paper can be placed between the bars and side plates and moved side-to-side to confirm that the sides really are the same height and in-plane. Pictures when it happens.

[Edit] Thinking more about it, there's no reason that both side rails need to be attached at the same time. The two reference surface plates can be placed next to each other, and a much shorter bar placed across the top, so no need to extend all the way across the 36" surface plate.

Or that's the theory...

 

[kb58]

Mornings are spent replacing/repairing siding on the house, and teaching myself CAD in the afternoons. I chose Alibre, a CAD package that is not subscription-based. I figured now is the time to learn CAD, the incentive being to use it to design the router, but also to have the knowledge to enter parts to be fabricated on it!

Manufacturer CAD models were used where possible, but for the most part, everything had to be measured to generate the component models. I included a shot of the rather enormous and heavy Y-axis roller guides and rail - those scissors are standard size! Most everything is on-hand, including the touch screen monitor, controller board, servos, and what really impressed me, a full-featured "mini pc." It's the small black box on the table.