Hey all. After years of wanting and saving, I have purchased a CNC machine! Since I don't have a precision mill, making one myself was out of the question, so I finally ordered a CRP4848 kit, legs, and electronics from CNCRouterParts. In total, the order was over $5,000 before shipping. I was so excited!
Unfortunately, I ordered the machine and parts over a month ago, and all I have received so far are aluminum extrusions from some third party company. That's right, 136 pounds of aluminum, sitting on my dining room floor doing nothing, for a month. The guy from CNCRouterParts emailed me once a long time ago with an update, saying he had no idea when the rest of the order would ship. Great update. Then another email when he told me it would ship in 5 to 10 days. Well, that email was 10 days ago, still nothing else shipped.
So I guess I'll review the parts I have already. First of all, the aluminum doesn't look precision milled at all. From the tool markings, it looks like they just used some sort of circular saw to cut the aluminum. Ridiculous! See the attached picture. What is the precision going to be from that, .063 inches maybe? I was hoping for 0.001 inches. Maybe I'm naive, but I thought parts would be precision machined for $5,000+ orders. Next, look at the holes drilled and tapped into the aluminum. I don't need calipers to see that some guy just eyeballed it. No precision machining or drilling whatsoever. Very disappointing. Of course, the aluminum hasn't even been deburred. Super. The entire reason I bought a CNC machine is because I don't have the tools to machine precision parts...and this is what I get?
I'll continue posting pictures and updates if and when I ever get the rest of the parts. I am most fearful for the linear motion component. I am hoping the ground rails will be accurate enough, that is my biggest fear. The pro machine was out of my price range, so this one will have to do. I'll post accuracy measurement when I have them. So far though, I'm disappointed in CNCRouterParts. Not just for zero quality control, but also for not shipping my order for over a month. If I would've known that, I would've bought elsewhere.
Terrible, I ordered a CRP4848 and it took almost exactly 3 weeks for all the parts to show up. This information on believe was relayed to me on the confirmation email, that shipping was 2-3 weeks. The aluminum showed up only 1 week after ordering for me. If you want an update on the order just shoot them an email I am sure tehy can give you an update.
Not defending them at all, but it was probably cut on a cnc cold saw which is the fastest way to cut that material, you will probably not see the finish after its built and if the saw if setup right it will be accurate.
The tapped holes I would use a horizontal mill to tap them.
You can check the taps by screwing some long bolts in and see if there are even with a square, same with the cuts.
If there not debured you can use a counter sink to clean the edges of the tapped holes easy enough.
Even without inspection tools you can still get an idea how well the parts are made.
I'm not so much concerned about seeing the finish as I am about accuracy, and for that reason, I'll definitely have to deburr it. Not just the holes, but all the internal edges so it can be flush with whatever it intersects. I hope you're right about it being accurate.
That's a good idea, once I get some bolts, I can check if they're square with a nice, precision square...but unless it is some weird optical effect or something, there is no way those holes are square.
My confirmation email never specified shipping time, but I remember either just before or after the order completed, the website said it would take two weeks. But we're double that now, I mean, I ordered this thing in late June, tomorrow will be August I wish they could have just sent the legs, or the smoothstepper, or something to keep me busy while waiting. I don't mean to sound too grumpy...I'm just annoyed and needed to vent
First of all, I'm very sorry it has taken so long to deliver the rest of your parts -- we got absolutely slammed with orders in June, which has traditionally been a slow month for us. We've been adding people to our staff and working to increase inventory, but are still struggling to catch up. I'll look into your order personally tomorrow to try and get things moving for you. You're completely justified in venting, and I apologize for the lack of communication on your order.
The extrusion you received is cut on a automatic aluminum jump-saw, which is pretty typical and is usually quite accurate in terms of length and squareness. As to the tapped holes, the holes themselves are actually formed during the extruding process, and they are then tapped (there is no additional drilling), so they are inherently parallel to the extrusion. I agree the 8020 factory could have done a better job deburring, and we'll talk to them about this, but I don't think you should have any functional issues with your assembly, especially since the tapped holes really only hold the bumpers for the machine.
We want you to have a good experience with your machine build, and I'm sorry we haven't lived up to that so far -- we'll definitely get things going for you as quickly as we can.
I ordered the PRO4848 back in May and it took about 3 weeks for everything to arrive which beat the quoted 4 week lead time. I think these guys are very honorable and will ultimately make you satisfied with their product....just my two cents
That is typical for 80/20. Not saying it is bad at all but it is normal for them to cut material and drill that way. I built a PRO2448 and all of my extruded material went together perfectly even after having it look as yours does. You will have to be carefully precise as you assemble the 80/20 material on your build no matter anyway. It should all go together fine provided everything is carefully assembled.
Your extrusion comes from 80/20, not CNCRouterparts. In all my dealings with CNCRP, I can say that I've always received my parts quickly, sometimes shipping the same day. I'm a huge fan having owned a machine made from their parts for several years. If you don't like their parts, send them to me... I'll put them to good use P.S I just ordered a part from them this week... got here in 2 days and I'm in Texas!
I just assembled my extrusion early this week and it was less than 1/16" out of square. I don't see any way of getting it perfect without a lot of work with shims. The corner brackets pretty much dictate the position and square-ness.
After finally getting the gantry squared up, it compensates for the base being off. I mounted the motors on the x-axis last night and everything seems to remain square. I'll find out when I'm able to make some cuts. I'm sure there are some adjustments that can be made to get it cutting fairly square if it's needed.
Hi all, I have an update! I spoke to Cory on the phone this morning, and I've just received 4 tracking numbers. Looks like most of the parts are now on their way, so I'm happy
As far as squareness goes, I'll likely check the squareness of everything at every step of construction with an INCRA precision square. I'm hoping to beat even 1/16th inch...even though is sounds small, over 48 inches, that is still over a thousandth of an inch off per inch.
Just got 95% of my cnc put together from cncrp. My experience has been nothing but outstanding. They are extremely professional and their products have reflected that. Im glad to hear they've gotten you taken care of though.
Hehe, big things have small beginnings...But 4 packages are finally arriving tomorrow. 36 days was a long time to wait, but hopefully it'll be worth it. I actually tried to go back to make the original post a little nicer, but couldn't find any way to edit it. Oh well, I'll post some pics and measurements as the build progresses.
Hey all, just an update My beautiful router is starting to take shape. Everything so far is very level, and the largest error from rail to rail is less than 1/64th inch near the very back, but for most of the distance, I couldn't measure any error. It took a ton of time to get that precision though. I made some pretty big mistakes that cost a lot of time. Some things I've learned:
1) Don't bother spending time squaring the legs, since you'll just have to loosen it up and expand it to fit the base of the router later.
2) Assemble the base (with 2 or 3 supports is good enough) on the floor, not up in the air on those legs. Use a precision square for every beam.
3) Definitely use pipe clamps to make sure the beams are flush. I redid the base because I later measured it was off by 1/32" at one end when measuring across. But after that, I couldn't measure any error in the metal frame at any point.
Other thoughts...I'm not sure how much I trust the legs, I'll reinforce them later. No matter how tight those bolts are, they still shift around, then I have to re-level the base. Also, I think they could use a second bolt at the top of each leg. With just one bolt, they swizzle way too easily. Also, having the legs fully supported with a diagonal and horizontal beam for every side will make them much more solid. I don't include the machine base, since those top joints swizzle.
One problem...the racks I got were 52.125", but in the assembly drawings and 3d model i saw they were 54". Because of that, I didn't know exactly where to put the rack supports with respect to the ends of the machine...so I just split the measurement difference at each end...hopefully that's okay.
I also found 4 curious little pieces of metal in the bumper bag for CRP110...Not sure what to do with them, so I just guessed, lol.
You need to measure your table on the diagonal to determine square, measuring across only determines if the frame sides are parallel.
The shortened racks are one of the infamous changes that have been made and not documented. Since you centered them, you will be removing(loosening) them and repositioning them. Another great feature of their documentation.
The little metal plates you refer to, I believe it's the plates you have behind your bumpers in the pic, are for the prox switches and go on the backside of the bumper bracket. Yes, more of that wonderful documentation.
Good luck moving forward.
You've done a great job getting your base together -- the most important thing is to have the two steel rails parallel to each other. Everything else can be handled later, and if you setup dual homing switches on the X and X slave (recommended) you can auto-square the gantry every time you home the machine. We have one customer who put their machine base together quickly and ended up with one bumper was offset from the other by almost 1/2". He didn't bother to fix it and still cuts exceptional (and large) workpieces on a CRP4896 using dual homing switches. Not saying this is the best approach, but you don't need to stress about this too much.
The 52" racks provide more than enough travel for the machine since the gear only touches the rack at one point, so placement doesn't need to be precise. When you mount the rack and pinion drives you will notice that the pinion gear is biased to one side -- you just want to bias the rack in this direction. The actual spacing of the rack clamps isn't too critical either.
The extra brackets in the bumper kit were included by mistake -- they are for the prox switches, but you have a newer X bumper design which already has tapped holes for M12 threaded prox sensors, so you don't need the brackets if you decide to add switches later.
Hey all. I encountered a bit of a snag assembling the Y axis. Like the website suggested for the steel rails, I used the z-axis motor mount as a spacer and meticulously straightened the rail. Now, those 5 aluminum supports/whatever that fit in between the rails is a hair too big. I can't slide any of them between the rails. I see three options, but I don't know what is best:
1) Forget those 5 pieces of metal ever existed
2) File down one side of each piece so it'll fit between the rails
3) Undo one of the steel rails and use those aluminum pieces as a spacer
I'm also having a problem with the gantry risers. I can't seem to make all 6 bearings rotate at the same time for either riser. Individually, each bearing block is fine. But when tightening them to the gantry risers, not all the horizontal bearings rotate at the same time. On a scale of 1 to 10, how important is it that all 6 bearings make contact? The risers don't seem to have any play at all, so that's good. Would it be difficult to adjust those linear slides once the Y axis gantry is installed?
Also, on of the risers runs smoothly until the last 2 inches, then grinds to a halt. Does this mean the steel axis isn't straight enough? It would be a serious challenge to make it straighter than I already have.
On your gantry, I'd choose option 3 and loosen the bottom rail so you can install the rail clamps. These provide additional pressure holding the rail down, and also serve to keep things in place a bit better if you ever crash your machine so you don't need to re-adjust your rails. The top rail should now be straight and well positioned for the rack and pinion drive spacing.
On the gantry risers, on your scale of 1 to 10 for keeping all 6 bearings rotating, it's about a 2 The system by design is a bit "overconstrained by having 4 carriages, so it can be difficult to get every bearing in contact at the same time, but this is not really important. You can loosen the bolts that hold the carriages to the gantry riser after the gantry is on later if you want to adjust them, but it's probably not worth doing until you break the machine in a little.
On the riser that is stalling out, this is probably not a straightness issue, and is likely just due to a localized high spot on the rail. I would loosen your vertical bearings slightly on this unit, and again re-tighten after you have cycled the machine back and forth a bit.
We've had these discussions with other customers before, so we'll update our tips and tricks document with some of this information this week as well.
Alright, I re-did the y axis rail and inserted those pieces of metal. I had trouble at first with some rough spots when test rolling the high z plate. Dial caliper showed there were some places almost 20 thousands off! I was able to pull the max deviation to +4, -2. Rolling the high z plate is much smoother now, but for most of the rail, there is a hair of play if I put my hand under and push upwards. I'm going to continue the build, since getting a tighter tolerance on those rails will be very difficult. I put all my strength into my clamps to bend those rails into place.
Quick question. For the high z plate, those bolt are not accessible by a wrench. I'm guessing a 3/8" socket wrench is the required tool...but is there clearance for that? I'd hate to go out and buy one, only to realize later that it doesn't fit.
Epic CRP4848 Build Thread!
I wish they could have just sent the legs, or the smoothstepper, or something to keep me busy while waiting. I don't mean to sound too grumpy...I'm just annoyed and needed to vent
P.S I just ordered a part from them this week... got here in 2 days and I'm in Texas!
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