I think the consensus for this mod is that M4 is the way to go. My M4s slid in between the makerslides pretty easily, but I could feel there wasn’t much room. I’d go as far as to describe it as a “slop fit,” because the tolerance on drilling your holes down the centerline from human error artificially inflates the necessary gap to get the screws through. I had to do the mod twice because my first attempt was with some clamps and a hand drill.10 thou left and right of the centerline here and there was enough to make it impossible to pass all 10 M4 screws through on my 500mm machine. So, I bought more aluminum bars and used the drill press at work and deburred, then it all went together. I’d be hesitant to do M5s unless I had another larger CNC to mill the holes in the bar stock perfectly.
Hi guys, I am new to this forum but couldn’t help replying to the thread as I have tried both the M4 bolts and washers between maker slides and the drilling x gantry and fitting plate between. By far the most effective is the bolts through the maker slide!
If you intend to drill the maker slides you must make sure you have the drill in the right place to avoid the channels that the end plate screws mount into. Also when reassembling make sure everything has been cleaned up and there are no burrs anywhere. Make sure to pre-thread the right hand Y stepper motor cable before inserting bolts. Also I used 2 pieces of 2mm x 40mm x 1000mm aluminium from B&Q (UK Home Depot’ish). I did not have to cut the plates at all and everything just dropped in. I used these bolts and nuts from Screwfix (UK tool supplier) unfortunately supplied in packs of 50!!!
B&Q (diy.com)
Aluminium Panel (Plate) (L)1m (W)40mm (T)2mm Product code: 3232630604359
Screwfix (screwfix.com)
JOINT CONNECTOR NUTS M6 X 17MM 50 PACK (83521) £4.99
JOINT CONNECTOR BOLTS BZP M6 X 35MM 50 PACK (87106) £2.59
The heads of these connectors are flat and miss all important bits of X carriage.
Total time for conversion/upgrade <60 minutes. Result is a super stiff Z axis - result!
Happy to advise if required but super easy to do.
Hello,
can someone give me the dimension of the braces (with holes position) in mm? I have disassembled the machine to make some upgrade and I have a friend that can cut me those, but need the exact dimension.
Thanks
I’ve finally got around to doing the 30 minute X axis - or so I thought, turns out I’ve actually done the 60 minute mod 
Top piece is 12mm x 3mm aluminium, drilled and countersunk for M5 screws. Bottom piece is 32mm x 3mm mild steel bar, drilled and tapped for M5 screws. The most difficult part was making sure that the holes, especially the tapped one, were in perfect alignment so the Makerslides could clamp together nice and square.
Not sure about the 60 minutes, took me the best part of yesterday to drill/tap the two bars!
More images of the job here. http://imgur.com/a/Re4tN
Safety Alert! Or perhaps idiot alert might be more accurate.
Prior to painting the 32mm steel bar silver (to match the Makerslide), I thought I’d remove the mill scale you get on hot rolled mild steel. The standard way to do this is with hydrochloric acid as it’s very hard surface that takes some serious effort to sand/grind off. OK maybe the lazy rather than standard way
I got an old plastic bucket from the shed and put it outside well away from the building, rubber gloves and safety glasses (full face helmet style), old clothes, a container of water - just in case. Gently poured a little acid on the bar over the bucket and waited for the magic to happen.
I should have checked the bucket more carefully, turns out it contained about 50mm of fine, aluminium fillings which generated lots of unexpected hydrogen? gas, smoke and heat. Got a good lungful of fumes before I managed to pour enough water in to stop the reaction.
Next time, it’s the grinder…
What do you folks think of the upgrade?
The wide maker slide?
It would be great to have someone measure and post the deflection for each 
To be honest, it won’t be much stiffer than bolting the two slides together, but it’s far more convenient and cleaner. Also, whenever you bolt extrusions together, there’s always a chance that you’ll add small deflections that will impact accuracy. That mechanical uncertainty is eliminated with the wide beam.
A nice comparison would be both mods (30 and 60 minute).
Incredible problem solving…
Perhaps this will allow me to move up to the 1800mm X-axis. I do however have one minor question for you:
What size bit did you use in your drill press, Sir?
Just want to say a big thanks to everyone who posted mods and advice - I was trying to make some test cuts in Aluminum with my stock xcarve. I was getting a lot of chatter, drfits, etc… but between this upgrade, buying better end mills, bracing the y axis, chip blower, and finally upgrading to a Dewalt 611… I finally got some decent test cuts on my scrap aluminum and now I am ready to give some real world projects a go. Thanks again to all.
Deflection with new rail is .003 old rail no mods .1 (if i remember correctly) using one finger lift.
Will get back once i remeasure.