[jdunham]

Greetings CNC'ers! First off let me apologize for another "I'm a newb and I don't know what I'm doing" threads but I'm hoping that by publicizing my build here that I'll get some sound advice and good motivation.

My wife owns her own business out of the home doing monogrammed gifts of all types and she came to me with a request. One of the things she sells (and sells a lot of) are wooden monograms cut from compressed balsa wood. And since right now she only resells them we thought we'd look into what it would take to make them ourselves. Long story short, I end up in the world of wooden CNC machines and now I think I've gotten more excited about it than my wife. So here goes!

I've been doing a lot of research/reading/learning the last couple of weeks and I've decided to go with the 24x48 Solsylva build. Several factors played into this decision. Cost probably the number one reason but I also was drawn to the fact that I could use a lot of materials from local home improvement stores and because I have a pretty modest set of tools available to me. What I'm hoping to gain is a good foundation so I can make future improvements to the Solsylva or to build another machine altogether. For now I've decided to use the plans with very minimal tweaks just so I can follow the instructions and not burden myself with things I may not completely understand yet. I'll be going with the wooden gantry and Z-carriage versus the aluminum and I'll be going with dual leadscrews and single motor on the X axis.

So to keep me from changing my mind I had to go ahead and get started. Day one I got the frame for the bed assembled.



Day two I got the legs done as well as a second frame that will be used as a shelf below the bed. I made a short trip out to my Dad's house and stole his drill press so I could get precise holes drilled for the leadscrew mounts.



Tonight I'm hoping to get the legs mounted and hopefully get the shelf mounted as well.

Wish me luck!

[Devastator]

You've got a good start. I am building a Solsylva 24X48 too: http://www.cnczone.com/forums/cnc_wo...lva_build.html

I'm to the point of figuring out the dust boot, and limit/home switches. I've already made some cool stuff with it though. My advice is to make sure to do a little something on the machine every day or your build can stall and you forget where you were in the build when you start back up. I did that a few times.

Good luck with your build.

[jdunham]

Thanks for the advice. I've visited your thread several time during my reading to check up on it. You actually gave me a good idea that I had not thought about when is comes to dust collection. I have an old house with an unused whole house vacuum. It's unused because we found out that it likes to kick on by itself in the middle of the night for some reason. Perhaps once I'm ready I could modify it somehow to work as a dust collector.

Last night I worked on getting the legs mounted to the bed/shelf. I was stalled a bit after I noticed that I had drilled out one of the leadscrew holes on one of them incorrectly so I had to remake one of the legs. That's what I get for working on it too late on a weekday I guess. After that I was feeling energetic so I went ahead and made the pipe supports and got them mounted. Well almost, I ran out screws right before I finished so one of them is still held on with clamps.

[Devastator]

Wow, you are really making progress. I started building mine exactly like the plan set too, but all of the wood warped. On the second go around I changed the bearing mounts. They are add on mounts made from steel rectangle so I can get more adjust ability out of them. I was afraid I'd get it all done and not be able to move the bearing blocks around enough to eliminate binding. I'm glad I did this because alignment was a snap. If you want any speed out of your machine, you must not have any detectable binding. Keep up the great work.

BTW, what leadscrews are you planning? I recommend 5 or 8 start. I used 5-start.

[jdunham]

I plan on using 5 start leadscrews unless someone convinces me otherwise. The way I understood it, 5 should be more than sufficient.

So did you use wood or plastic for your first set of bearing mounts? I have access to a 3d printer here at work and I was toying around with the idea of printing out the bearing mounts. Just not sure how strong that plastic would be versus cutting board plastic.

Also, which parts of wood were starting to warp so I can keep an eye out for it?

[Devastator]

Yes, 5 start is good for speed and you still have good resolution. 8 start is better for speed but you get less resolution. I used black phenolic for my bearing mount blocks. It is hard and stable. If I were to do it over, I would just use some flat oval plates that look like muffler flanges to just pinch the bearing and hold it where I want it. I fabbed one for an end of my Y after I had to redo it when my stepper shaft broke. It was super easy to make and alignment is really simple. There is a photo on my build log.

On the wood that warped on mine....they were the X rail supports and the Y gantry. The parts the pipes mount to. They twisted real bad after about a week when the wood started drying out. I remade them out of laminated birch plywood and bonded and screwed some angle iron for good measure. You'll find that when you tighten down the pipes, the washers sink into the wood and the amount you tighten each one is arbitrary so they may not be all equal. I was also afraid that once the wood dried better they might become loose. With the angle iron they don't have this problem. Everything is level and no deformed wood.

[jdunham]

I started working on the X rails last night and it took me a couple of hours to get one close to where I wanted it. For some reaon I had a heck of a time getting the holes drilled in the pipe evenly. On a couple of them I had to widen the holes to get the bolts to line up better. For the second rail I might have put togethr a jig or something to help out. As it stands theres only a tiny bit of movement in the rail when it's not tightened and that may come back to bite me when it comes down lining things up later. We'll see. If I have to remake them I will.

[Devastator]

For some reaon I had a heck of a time getting the holes drilled in the pipe evenly.

Harbor Freight has a jig for drilling round objects that will help as well as using a punch and center drill. I wouldn't fret about the looseness however. The way it goes together, you need some play to get everything together, then tighten everything slowly and evenly checking for binding along the way. That step took me two weeks to get out all of the binding.

The manual says that bulging of the pipes is ok after you tighten them. It is really not because the bulging is not just isolated to a small part, it deforms the whole thing slightly and you will get detectable binding. Not extreme, but enough to feel. I made custom rounded nuts to go inside the pipes. When the manual mentions filing down the deformities caused by tightening, you know it is a bad idea.

[jdunham]

Good to know about that jig. I'll be sure to check that out before I do any more drilling.

Also I discovered that the length of the threaded studs wasn't long enough for my taste so I might cut some longer ones. As it is I don't have enough space for two washers and the nuts inside the support beam. I might try rounding off those nuts as you described as well. Thanks for all the input. You've already been a huge help.

[revwarguy]

Hi jdunham,

Welcome to the monkey house! I built one of the tables you are making - you can see the log of it here. It might have something of interest in it. If you have any questions about it, fire away! I used 5 start screws, and I think they are right at the sweet spot.

[revwarguy]

As far as drilling into the pipe, drilling a hole on a curved surface is one of the more difficult shop tasks. The HF jig mentioned before by Dev is here:
Attachment 190150

This is sometimes called a V block. It is essential to clamp it down somehow. Once you have the first hole drilled, insert a rod to fit in the new hole, which you can check each time with a level to make sure it is still upright for the next hole. To make sure the pipe is directly centered over the bit each time, you can use one of these:

Attachment 190152

This is a type of center finder. Grizzly has them for $3.75, #H2940. Chuck the cylindrical part in your drill press chuck, and move the pipe under the inverted V part until the indicator points straight up, then clamp. Even then, the drill bit will want to wander on the pipe surface. To mitigate this, try a center drill also recommended by Dev, like these:

Attachment 190154

These are also available at HF. All you have to do is get the hole started, and you can switch to the proper sized drill. Hope this helps,

[Devastator]

Thanks for all the input. You've already been a huge help.

Hey, no problem. I've learned a lot from my build and if I can help anyone avoid the same pitfalls, I'm happy to. I will say that the machine you are building can do some serious work if you build it right and do some smart upgrades.

If you haven't fully decided on the drive configuration for the X, I'd go two motors and slave them in software unless you don't need a lot of torque. That is currently my biggest limiting factor on depth of cut and speed. I'm running one motor and two belts. The one long belt just looked too sketchy for my taste. I may redo it to use two motors when I get the money for a new 4 axis driver. My other option is to go up to nema 34 but then the drivers get even more expensive.

[jdunham]

I was planning on going with this setup from cncrouterparts.

http://www.cncrouterparts.com/3-axis...-kit-p-74.html

Naturally I only know what I've read so I heard that running slave motors could sometimes be frustrating to deal with. I was going with a single motor but I had not made up my mind on one belt or two though. I was leaning towards one for simplicity.

Also thanks for those links. Now I know what to look for at HF.

[jdunham]

Also I forgot to mention that I won't be needing a lot of torque initially. We'll be mostly working with compressed balsa wood starting out but I'm sure that'll change as we start getting familiar with the machine.

[CarveOne]

I use the CNCRP four motor kit on my 3' x 4' steel frame machine with 5 start lead screws, and highly recommend it. Get the motors with 3/8" shaft and get the CNCRP or DumpsterCNC anti-backlash lead nuts for it. The 3/8" shaft has more gripping surface for anything that uses screws to compress the delrin or aluminum coupler onto the motor shaft. When Mach3 is configured properly the dual motor axis setup is generally very reliable. On my first attempt at using it I had a lot of problems and it turned out to be a wrong setting in Mach3. Both of my machines use dual motor X axis now and I wouldn't use anything else.

I have all of the tools that revwarguy recommended and they are all good recommendations. In addition, get a set of 135 degree split point drill bits. This type of drill tip will start cutting without walking around the rounded surface. Just use light pressure at the surface and increase pressure once it has made a small dimple in the material.

[jdunham]

Hmmm. So that's two votes for slave motors on the X axis. Sounds like I might need to give that more consideration.

[CarveOne]

And don't forget that you will have almost 760 oz pushing the gantry weight, and it's pushing each end of the gantry equally. I check my gantry squareness before each cutting session just to insure that it doesn't start cutting with a small error if any steps are lost in the previous cutting session for whatever reason. If you have some binding on one side or hit something like a clamp it can lose position on that side.

You can set up the auto squaring feature of Mach3 using limit switches or install hard stops with adjustable screws to set the alignment by slowly running the gantry up to the screws, turn off the motors, and manually move the lead screws against the stops then turn the motors on again.

[Devastator]

Naturally I only know what I've read so I heard that running slave motors could sometimes be frustrating to deal with.

David Steele overstates that in his manual. It is actually more frustrating to lose steps because your single motor does not have enough torque to push the tool through the stock.

Even though your current use is for balsa, you will eventually want to cut some birch plywood.. That's where I notice the lack of torque on the X. I have to limit my feed and depth of cut to accommodate the weak X.

With the G540 and mach, the slaved axis is no big deal.

[jdunham]

That settles it then. I know for a fact that we'll eventually need to cut some more dense woods later on.

After the initial build is done, what options will I have for cutting my own upgrades? Do you think I might be able to do some limited work with aluminum if I stick with really slow feed rates?

[CarveOne]

When you try cutting aluminum, don't use soft aluminum like is used for window trim. Use a harder grade like MIC6, 6061, or 7075. Use a little WD-40 for lubricant to help prevent aluminum from sticking to the cutter. That will break cutters. You will need to try different feed and speed rates to determine the optimum settings for your particular machine.