Thoughts on Stiffening mod

The purpose of the printed parts is to allow the nut and fastener head to have a surface to rest on and distribute the force over a large area inside of the makerslide. The threads of the fastener are held by the nut, which is held in place with its corresponding 3D insert. The inserts slide down the inside of the makerslide similar to how you slide a t-nut in the t-slots.

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OK I see how your doing it now. I don’t have a 3D printer but I do have a CNC milling machine so I’m wondering if I could make the inserts from Alu. I would drill and tap the nut side and drill and counter bore the bolt side. Just need to come up with a cutter to get the outside profile.

Dave

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This turned out well. There is enough room for the y-axis motor cable to easily pass through after the hardware is fastened. The printed nylon inserts flex enough so that when the fasteners are tightened they conform to the contour of the makerslide, distributing the force very nicely.

I ordered the steel through McMaster. Unfortunately, it arrived bowed. I asked for a replacement, and that was also bowed; I suppose it may be due to how it’s stored in the warehouse. I was able to work the steel bar until it was straight. Other than that, their steel is nice, but it may be worth sticking with a local store so that you can select the best steel bar for your project.


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If VHB tabe is used, then the metal thickness will have to be reduced to 1/8". The tape is 1mm thick, so when applied to both sides it would take up 2mm (1/16"). Not to mention it would be permanent. If you could ensure perfect alignment then it would certainly work.

Hello. Sorry, total newb here. I am researching easy mods to do to my XCarve when it arrives in a couple of weeks. Do you need to drill holes for these screws/bolts (on the extrusions I mean)? What kind of screws and washers are these? I found the metal part itself (McMaster-Carr) but not the screws.

You will have to drill your own holes. The fasteners I used on mine are furniture bolts, which I got at Lowes. You can see my build video, which has Lowes SKU numbers for the bolts at X-Carve Maintenance/Troubleshooting Videos - Add Your Own!

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Has anyone considered just using aluminum bar and taking it to someone to TIG weld it? I’d imagine just a series of 1" welds on both sides and top and bottom would be pretty quick. The only concern would be keeping it all cool so it doesn’t warp.

If you are talking about welding the aluminum bar to the maker slide rails you have 2 problems. 1 You would have to remove the anodizing where you want to weld. 2 There is no way to keep every thing straight. Aluminum loves to warp when welded and there is no good way to straighten it after the welding.
Drilling and bolting does not introduce warping if done carefully.

Dave

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I’m thinking of doing the steel bar mod…are there any negatives for doing this? not being an expert of I wonder if the added weight of the steel would stress the motors and make them less responsive. could anyone comment on that I’m on the edge on this…thanks

We have seen a lot of folks make the mod with both steel and Aluminum and I don’t remember seeing any one report any problems.
I think it would be best to have nema 23 steppers and not nema 17s.

Dave

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The type of movement the gantry does is twisting along its length. Adding an open-channel (T, C or L cross-section) will have very little effect in this mode of deformation. The main thing that will help is fastening the two maker slides against each other to keep them from moving relative to each other. So, long story short, it really doesn’t matter what kind of material you use. Aluminum is fine, and MDF would even give you close to the same performance.

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I’ll report problem for you Dave, if you remember we were discussing non parallel Y axis problem couple weeks ago.
That was my mistake while drilling maker slides. Hole wasn’t absolute angle, causing maker slides pulling each other unevenly. Result of that, pulling Y axis holding plate a little. The bottom line is not to material using for stiffness, making those screw holes straight under drill-press is the most important key I believe. Thanks for your advises for troubleshooting. I’m back to perfect condition again.
Cheers.

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Alan

I’m glad you were able to solve the problem. You have hit on one issue that can arise when doing the stiffening mod.
With 99% of X-Carve owners not having a milling machine in there shop to set up fixtures on to drill the holes in the 3 pieces dead on, owners have to rely on what they do have.
If an owner has a drill press and clamps then with careful set up good holes can be drilled.
If all that an owner only has a cordless drill and clamps then it is a good idea to drill the holes in stages. Start with a smaller drill and work up to the final size in a couple of stages. If you are using steel for your center plate it is easier to push a small drill through first and then larger drills.
One trick that owners with just a hand drill can use is get a piece of hard wood that you can drill a good square hole in for your starter drill. after drilling this hole check it with your square to insure that it is square with the block of wood. Now you have a drill guide that you can clamp to the work and use to get your holes square with the MS.

I offer this information to help others that are thinking of making the stiffening mod to there machine. This mod helps the X-Carve be a better machine and can be done by all owners beginner to advanced.

Dave

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I didn’t even remove my rails to drill them. In fact, I didn’t disassemble anything to do this mod. The only thing I did was remove the cable from the middle of the maker slide and loosen the mounting bolts on the ends. Then I drilled clean through. No misaligned holes. And just an FYI, you do not have to re-route the wire, say thru the top channel like some have. If you take your time you can thread it back thru the maker slide with the bolts running thru it. The wire should have space either above or below the bolts.

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Hello there. I just wanted to make an observation about this particular part. It certainly is the right shape and thickness. However, the horizontal portion is too wide. The v-wheels cannot roll freely with this part installed. In fact, one cannot insert the carriage with the part installed. I actually tried.
At this point I have a couple of options but I think what I will end up doing is purchasing just a metal beam from Home Depot and drilling the appropriate holes. Trimming this part would be too time consuming.

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I am using an aluminum tee. It was purchased as a 1 1/2" wide and tall piece. I simply trimmed (the bottom, horizontal section) to 1 3/16" wide on my table saw with an appropriate blade and safety devices. It fits perfectly on the underside of the gantry using the same bolt-through treatment as the flat bar. I will post some pics when I get a chance. I believe the aluminum tee is more rigid (and lighter) than a flat bar. The bottom of the tee cradles the makerslide and makes it virtually impossible to sag–it holds itself up.

If you are uncomfortable cutting aluminum, or are not equipped to do so, a local machine shop could do this for you for an affordable price.

I had a steel flat bar in place but decided to try the tee due to the observation I had of the gantry “bouncing” a bit during fast direction changes. There was no longer any noticeable flex, but rather a certain inertia present when the Y axis changed direction. Fastening the whole frame to the table may have eliminated this, but my thinking was that over time the extra weight of the steel may wear on the motors and belts. The aluminum tee is half the weight and is, in my opinion, a better solution. Sag, bow, and twist are gone from the gantry–as well as the inertia bounce. I’m not an expert on the physics by any means, but my eyeballs and test cuts tell me the solution I have implemented works the best for my situation.

How necessary is this mod? If all I need is 1/32" accuracy from my machine, will I even be able to tell? I don’t have my machine yet, so not sure. I’m concerned about adding weight to the already heavy gantry with the dewalt on there.

Ryan, I would consider this mod almost essential, especially if you can do it during the initial build. The additional weight is negligible for the two Nema23’s, not sure how the 17’s would handle the additional weight but I would guess that it wouldn’t be much of an issue. I have a single Nema 23 running the Z axis of my milling machine and I’m sure I’m asking way more of that motor than the X-carve is asking of the dual motors on the Y axis. If you clamp the extrusions with the steel/aluminium bar between them and use a drill press to drill the holes it’s a fairly easy operation. Just take you time to make sure the extrusions are square to each other and the bar doesn’t extend past the top of the extrusions and you won’t have a problem. Drilling the holes slightly oversized will give you some wiggle room when you are making the final adjustments to the machine

It is more removing chatter then accuracy.If you have you calibration right then accuracy follows by default. You will soon discover that if you got your machine ordered before they dropped the cheap motor with a collet adapter that they referred to as a spindle that you will want to move up to a trim router or a VFD spindle that will cut all day without crapping out.

Dave

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Here are some pics of the mod using 1 1/2" aluminum tee, milled down to 1 3/16" width. It ends up exactly even with the edge of the T-slots on the bottom of the makerslide and the top edge of the side T-slots.

This has proven to be more rigid than the flat steel sandwich for me, and the total weight of the assembly comes in at at just under 5 lbs. without the cradle. The steel mod weighed in at almost 6.5 lbs. without the cradle. It feels more solid than the steel as well. Almost like one solid piece; I can’t flex or twist it in any direction by hand with all the force I can give. The steel bar had a hint of flex on the flat side (bowing) but nothing top to bottom (sagging). That may be why I saw a spring or bouncing (kind of like a whipping backlash) action with fast direction changes on the Y axis. I am getting none of that with the aluminum tee.

The aluminum tee cost me $27 for an 8-foot section. I have enough left over for another 1000mm or two (almost three) 500mm X-Carve upgrades. Highly recommended if you want maximum rigidity using the stock makerslides. If someone really wanted to, there is enough room to add t-nuts and recessed machine screws to the bottom of the assembly. For me, the furniture bolts seemed more than adequate.

As a side note… there was an issue with an uneven spot on the “V” edge of the makerslide with the “X-CARVE” decal and it had to be replaced so the V wheels would roll smoothly. The pic without the decal is the final assembly with the new makerslide.

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