Beautiful work Gary. If those angle attachment bolts at the bottom will not be accessible, I am assuming you used Red Loctite on those?
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Beautiful work Gary. If those angle attachment bolts at the bottom will not be accessible, I am assuming you used Red Loctite on those?
Looks nice Gary!!
Quote:
Originally Posted by wmgeorge
Thank you, Bill. No loctite yet, but I will be using it. Probably blue, rather than red. If I ever want to break it all down, I don't what have to use heat to unscrew it. The assembly and attachment was just for photographic purposes at this point, so loctite wasn't necessary.
Gary
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Quote:
Originally Posted by Ntl
Thank you, Dan.
That's one beefy setup. Keep going....
Quote:
Originally Posted by davida1234
Thanks, David. Beefy is what I'm going for. Although this will mainly be a wood router, I plan to cut aluminum as well. In fact, I plan to use it mill to caps for the extrusion ends, hard stops, etc. Much faster than manual milling with all the setups, tool changes, etc I can also cut fancier shapes with the CNC as compared to my mill.
I've given thought to using 3/4" HPDE for the spoilboard top (re: your build thread), but I'm on the fence.
On profile/through cuts, I zero to the spoilboard, then move Z axis up the nominal thickness to the piece I'm cutting and hit zero again. My cam thinks I'm zero'd to the top of the piece and the thickness I set is nominal (vs. actual). So, for 3/4" plywood, which is less than 3/4", I tell cad/cam the thickness is 3/4" and Z=0 is the top of a 3/4" thick plece. As long as the offset for my touch plate is accurate, and it is, my bit will always stop at the top of the spoilboard, but never cut into it. With my other machine, except for when my Z screw coupler slipped once, it worked 100% of the time. Long way around to reach one conclusion: The cost isn't as much of an impediment as it might otherwise be, because my spoilboard will probably have a useful life of several years. (For two-sided carving, I'll use a sacrificial piece of MDF for drilling locating dowel holes).
What keeps me on the fence? HDPE is slippery as heck. Maybe not as slick as UHMW plastic, but still slick. That makes clamping an issue. Up until now, I've used T-track ala Orange Aluminum (https://www.orangealuminum.com/t-tra...cessories.html) and cut maple blocks of varying lengths for clamping. MDF provides frictional resistance; nothing moves. I question how to get enough resistance with HDPE. I can see parts slipping around and ruining the job.
What technique(s) do you use for clamping to HDPE? Reaching under a 4 x 4 machine (actual frame dimensions 74" x 60") to tighten bolts won't work for me.
Gary
With MDF you have an option of using wood screws to hold down if needed. I use my track and clamps most of the time but its not always convenient.
Yes, HDPE is slippery and I do not advocate that you use it as a spoil board. But theQuote:
Originally Posted by GME
material checks most of the other boxes so it is a compromise you would have make.
It also depends a bit on your style of holding material on a spoil board. I personally
rarely use clamps as I don't like always making sure I don't hit any of those. Too easy
to break a bit for my taste. I almost always drill some holes in the material and screw it
down. If you are into serial production, those screw holes get bad pretty quickly in MDF.
HDPE does hold screws very well and doesn't go bad with screw holes but it is not as
easy to drive a screw first time into it as with MDF. A pilot hole works well but is not as
convenient as with MDF or BB.
I have both a BB plywood and HDPE as spoil boards for the Brygga, If you follow my
thread, you can see how it will fare. I will make some videos with clamping and screwing
down on the HDPE.
Thanks, Bill. I have never used screws in MDF. I have always used the t-tracks for my anchoring points. On my first machine, my biggest limitation with t-tracks had to do with the number of tracks used/spacing between them. I had them spaced too far apart, which sometimes created challenges when clamping things down. Small pieces were problematic, as were certain sized larger pieces. I was able to compensate, at least to some extent, by cutting maple hold downs longer, but I ended up with too many hold down sizes. Storing them started to become an issue. This time around, I plan to use more tracks and space them closer together.Quote:
Originally Posted by wmgeorge
I was fortunate to stumble onto the t-tracks Orange Aluminum offers. At $8.54/4' piece, they have the best price I've found by a wide margin., e.g., Rocker sells 4' for $30, Woodcraft $20. Spend $100 and shipping is free. They also offer 8' pieces at $17.08 each with the same deal on free shipping. You don't get colored anodizing, but not a big deal for me.
Gary
Quote:
Originally Posted by davida1234
Thanks, David. I'm thinking about BB for a base layer into which I cut dados for the t-track. I can then put MDF on top and cut slots to open up the t-track. The slots in the MDF will be the same width of the t-track slots, which means the MDF will overlap the top edges of the t-track. With this arrangement, you don't have to bother with screwing the t-track down. An elegant solution, but not one I came up with. It is explained by Peter Passuello at CNCnutz. He has some practical suggestions on his Youtube channel, CNCnutz. https://www.youtube.com/channel/UCQ3...lKOcjcaxkOfr6w, Episode 51, Don't Spoil Your Spoilboard, covers the basic idea.
I've been following your very interesting and informative thread. Is it your plan to extend your design to something as large as a 4 x 4? I like the rotating ball nut concept, and have enjoyed watching the progress you've made. You are a talented guy.
Gary
I know Peter Pasuello and his site from Joe's Forum.
He is a great guy and very resourceful.
Yes, I do plan to offer Brygga models for purchase.
Sizes will be from a 2x2 to a 4x4.
I am not sure yet if it should be offered as DIY kits,
semi-assembled or fully assembled and tested.
I wound up spacing my t-track at 3" on center. What I just recently did is clamp down a piece of MDF that is a true spoil board that I can screw parts to as well as mill holes in for indexing pins for two sided machining. So far it's working out well and my table top is still pristine. I wound up doing it this way for a job I'm running that is a bunch of nested parts that needed to be held down in the middle of the material. I found the setup is much faster when you just screw the material down and mill the indexing holes straight through the material into the spoil board. It's also cheap to replace once it's chewed up and only takes like 30 seconds to clamp down to the machine bed with the t-track.
Dan
I do mostly the same except that I screw down the spoilboard-spoilboard to the actual spoil board.Quote:
Originally Posted by Ntl
Quote:
Originally Posted by Ntl
Thanks, Dan. I've toyed with 3" t-track spacing. 3" or 4" sounds about right. I've also considered using a "removable" spoilboard for those "special projects," like 2-sided machining. I like using the blue tape and super glue method of work holding, but it takes more setup time than using t-tracks and hold downs. Tape/super glue does work nicely when you need support at more than just the edges. It's also good when you don't want to use tabs (for whatever reason).
Gary
I went with 3" just because it makes the math simpler for setting up work pieces and setting the WCS so far I'm liking the spacing. I started at the center of the table and worked outward. Originally I wanted to do a grid with the t-track but it was going to be a bunch of work to get it right. I still need to add two more rows since I ran out of t-track since I changed my spacing. So far I'm liking the setup though, eventually the plan is to install aluminum t-slot plate when I have the extra dough.
Dan
It's Y axis linear rail installation time. Here's how I did it:
I started out by borrowing an idea from CNCRP. They have a custom fixture they call a "rail alignment jig." IMO, it is a good idea for setting general alignment, but not to get the rail anywhere close to precise. CNCRP instructions tell the builder to fix one jig at each end of the axis, clamp the rail up against the jigs, and tighten all of the rail screws. That gets you a rail in a generally straight line, but if the rail isn't perfectly straight "out of the box", to a greater or lesser degree, you are going to get something shaped like a snake, or have a bow in one direction or the other. Even if the rail is perfectly straight out the box, just tightening screws can change things. Probably adequate for the user who just wants to get the machine assembled and running, and doesn't have the tools or skills to do it better. Good enough to work, but not anything like "precise".
My first step was to fabricate two alignment jigs. The pics of the CNCRP depicts a pretty think chunk of metal (probably aluminum). Since I decided that clamping to the jig was unnecessary, I used thinner metal. I used a piece of 1/4" thick aluminum angle. Since the 90 degree junction is too large to allow the angle to site flat on the extrusion, and aluminum angle is notorious for not being square on the legs, I fixed everything on my mill. Here's a picture of the finished product:
https://www.cnczone.com/forums/attac...d=419486&stc=1
I have to admit to a mistake. You will see 2 mounting holes drilled. I got my dimensions (I built it on the fly with the plan in my head) wrong, and 2 screws wouldn't fix next to one another. Turned out to not be an issue. One well tightened screw worked fine.
The next step was to locate the jigs on the extrusion. I placed them about 34" apart, starting at the front end. With all of the screws in the linear rail, but loose enough to allow me to flex it, I pushed the linear rails up tight against the two jigs. Here's a photo:
https://www.cnczone.com/forums/attac...d=419488&stc=1
Then, I placed my 36" Woodpecker straight edge up tight against the linear rail. (Note: the straight edge was one of Woodpeckers One Time Tools, which means orders were taken over less then a 30-day period, and once sales closed, the product is retired. This straight edge was ground to a tolerance of .0002"/12" - about as accurate as one could hope for. It is 2-1/2" wide and 7/32" thick. As between the linear rail and straight edge, the linear rail will flex first). Here's a photo:
https://www.cnczone.com/forums/attac...d=419490&stc=1
With the straight edge still pushed tight against the linear rail at the jig points, I use 2 C-clamps to hold the straight edge into position. I then used a piece of .001" shim stock to check for gaps between the linear rail and straight edge. I then started 3 rounds of tightening the bolts within the length of the straight edge. I started from the front and worked toward the back. The first round was to get the screws barely snug. Then checked for gaps with shim. None. Second round was to snug the bolts down about half way between barely snug and and fully tight. Third round was final tightening. All went very smoothly and easily.
The next step didn't exactly give me fits, but it made me do a bit of troubleshooting.
I removed the C-clamps and moved the straight edge toward the rear 18". That left half on the part that was known to be perfectly straight, and the other half on the unsecured part. I replaced the C-clamp at the forward end, and the 2nd at the rear. The front half was tight all the way along, but the rear part had a gap of around .002". I was able to flex the rail, but it wasn't regular along the back half the straight edge. So I tried again. Same result. Tried a third time. Same result. Obviously, I was doing something wrong, but that "something" wasn't obvious to me at the time.
When I regrouped, I put one C-clamp at the forward end, and a second at the midpoint. No gaps to the midpoint. Then, I added a third C-claim at the rear end of the straight edge. Success!!! I grasped the linear rail and held it tight against the straight edge as I when through the three rounds of tightening. Checked with .001" shim. Couldn't get it in over the 36" length of the straight edge.
Using the same successful technique, I moved the straight edge to the far rear and clamped it in place (with 3 clamps).
Here is a photo depicting the 3 clamps.
https://www.cnczone.com/forums/attac...d=419492&stc=1
Install of the Y-axis master rail complete.
Next up: Installing master rail on X-axis (gantry).
Gary
Looking good.
Grabbed a bag of popcorn and i will be following closely this post!
I was to build a machine a bit like cncrp pro 4x8 but i might start from scratch like you did !
Gary it appears your machine is going to be pretty much like the Saturn2, even to the placement of the linear rail on the top. That leaves you no up/down adjustment (other than shims) and subject to the straightness of the aluminum extrusion. The CNCRP places their rail on the side to allow adjustments, they seem to have a proven design with no issues with accuracy.
I don't think they mount them to the sides to provide adjustment. That's an adjustment that few of their customers would be able to do. They mount them with a jig, parallel to the rails.Quote:
The CNCRP places their rail on the side to allow adjustments, they seem to have a proven design with no issues with accuracy.
Extrusions are likely to be much straighter than steel, and short of mounting to machined surfaces, Gary's method is about as good as you can get. You certainly don't want to be shimming the rails.
Personally, I prefer side mount, as it potentially gives you a flat edge to edge table, with no interference from anything,
They use a Jig to aline with the top of the rail, side mounting gives them a way to adjust the up/down if needed. Same method CAMaster uses. On top your counting on the top of the rail being perfect otherwise you need to shim. There is a reason why CNCRP does what it does. Steel rails can also be ground flat, if needed. Why would aluminum be more true than steel?