My feed rates were limited by chatter with the stock 300W spindle. I just upgraded to an 800W GMT spindle and wanted to stiffen the x-rail at the same time. I inserted M5 50mm hex cap bolts vertically in the gap between the x-axis maker slides. They are a perfect fit for the gap. I used 5 bolts spaced about every 6.25".
I used a small washer on top (any larger would interfere with the idler wheels), and used a larger washer on the bottom. It is important to use washers which will not bend into the gap when the bolt is tightened. I used extra M5 waste-board inserts as the nuts, on the bottom.
I wanted to preserve the spacing of the x-axis maker slides so that the v-wheels would track true. So I clamped the maker slides together while tightening the M5 bolts, and took care not to over-tighten. It would be easy to get carried away with the wrench and force the x-rails apart, possibly damaging them. It doesn’t take much bolt tension to get the desired stiffening effect.
The x-rail is rigid now. There is no visible x-axis deflection when I press on the spindle in any direction.
I like this chatter-reduction mod because it
stiffens the x-rail substantially in bending and twisting
Brilliant, That’s what I’m trying to tell all this time. Those rails trying to move diagonally when forcing. I don’t think big heavy steel plate necessary. Great job.
I love this idea and I have been ready to upgrade to a Dewalt 611 but this mod had been putting me off of the upgrade for lack of drill press and I was about to buy one of them as well to be sure the holes were done right. If this works just as well then it will save me a big headache of tearing the machine apart and potentially screwing it up. Thanks! I wish they would sell a reinforced axis now that the standard spindle is the 611.
To be honest, I found the m5 bolt to be just a hair too big. I really would have to force it between the makerslides, and I felt like that was spreading them out just a hair, which is exactly what I don’t want. I found that some 3/16" machine screws with washers and nuts fit much more cleanly. Kinda makes sense, because everyone else’s steel bar mod uses 3/16" steel stock as well.
From previous threads/posts, the gap between makerslides is 4.75mm - based on the CAD drawings. I measure an M5 bolt as being 4.86mm. That’s a difference of only 0.11mm. Not sure if I’d worry too much about that.
I agree with @AlanDavis, yesterday I cut 2 pieces of 0.093 thick 1 1/1/2" X 38" acrylic and put them between the makerslides and used furniture bolts like the others to hold it together. It worked great and there is no more flex. I like what @MattWheeler has done here, it looks easier than what I did.
I loosened the bolts that hold the slides to the end plates, dropped an M5 in next to each end plate for temporary spacing, then placed the 5 M5 bolts with washers from the top, every 6.5 inches. I started in the middle, clamped the slides together, and tightened the 5 M5 bolts/washers. Then I removed the temporary M5 bolts near the end plates, and tightened the end-plate bolts.
From what I can tell, everything it lined up nicely.
Just got done with mine this morning, worked like charm !
6-32 x 2 inch screws
On top nr 6 washer and nr 8 washer (anything wider wheels were pushing on X axis motor side)
On bottom side 1/8 by 1 in washers with 6-32 wing nuts.
Now Inventables stop slacking and add 5$ worth of bolts with your kits.
It might flex under heavy stress, keeping bolt and nut big enough might give more rigidity. That bolt seems a little weak, especially the Phillips head. I’d rather to use 3/16" bolt with stronger nut and head.
I know its far from perfect. One thing for sure, I was able to flex the beam on router side easily with my hands before I’m not longer able to do that with 6 bolts in place.
Thank you all for the original
mod and the variants. I ended up using eight #10-32 x 2" machine screws with round heads, and some #8 washers.
I chose that number because they came in packs of four.
Installed before my first carve. Everything is working beautifully.
Thanks for this idea! It took some time before I got around to it, but I finally stopped by the hardware store and picked up the supplies. Super simple, super cheap, super quick to do, and it made a noticeable difference in the stiffness of my gantry.
I put 10 of these across the gantry with a 90mm spacing and used nylon lock nuts and large washers to create mor of a T underneath.
