yes there is a shoulder in the chassis of the machine where the rail sits/bolts against.
yes there is a shoulder in the chassis of the machine where the rail sits/bolts against.
So i got stuck into it and removed the old rails.
Cleaned and stoned and cleaned again, tapped the threads to make sure they're clean. Cleaned again and sprayed WD40 to make sure rust can't start.
Before install ill clean again before i mount the new rails as it gets dusty.
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Just trial fitting one of the rails. pretty straight forward.
Broke one of the bolts when tightened down the rail so i think ill replace all 52 of the bolts.
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Hi guys, just wondering what the torque settings would be for the rail bolts?
Are the torque settings critical or should they just be tight?
Thanks
Bart
Hi guys, Im just measuring the parallel on my rails and im getting 0.045mm from one end of the rails to the other. I dont have the manual which tells me if this is outside machines specification.
Just wondering if anybody can suggest this is ok or not??
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0,045mm = 0.00177165"
You want it better than that, if the Bearing blocks are Preloaded, if they are not Preloaded, I would still try for around 0.0006" / 0,016mm, you may have to scrape the shoulders where needed to correct it
Make sure you are using the correct edge of the rail; some are marked which is the Datum Edge / Reference Edge of the Rail, this edge has to go against the shoulder.
Mactec54
Just want to backup what Mactec said about the fact that here is a master shoulder on one of the rails. It's usually marked in some way. A line, a part number placement. Depends on the manufacturer.
Although it kind of appears that both of your rails have an edge to butt against, one will be a master. You might have to examine the old rail to determine which one. The same goes for the bearing trucks when you get to the point of mounting the saddle or table. Obviously the master trucks will be on master rail.
I see you only have three of the lateral postioners in place. You want all of them active while you're tightening down the rail. I've used a combination of light-medium force on the lateral pusher while tightening the rail bolt next to it. Contrary to things like cylinder heads on a car engine, you tighten rails starting at one end and proceed towards the next. I'd start at the far end in your picture and work towards the near end. (on the front rail) Turning the wrench into or towards the shoulder. That's how THK suggest to do things.
You might try placing your indicator on the side edge of the opposing truck instead of the opposing rail. Or check both. You can use the far rail shoulder positioners to help correct errors in the rail parallelism. The non master rail does not have to be hard fast against any shoulder. It's more important that it be parallel to the other rail.
Don't forget to double check the height of the table mounted ball nut yoke to the height of your screw ball nut. Take your ball nut measurement with the ball nut all the way towards the main bearing end of travel. This will eliminate any sag that the weight of the nut might have on the screw mid travel. Not sure if your trucks had shim plates in place or not. They may need adjusting for height.
On that note, it looks like your screw has not seen a lot of work towards the ends. Don't forget to move your work holding around on the table. Meaning don't always mount everything in the middle of the table. Spread the fun (wear) out across the machine's travel.
Even though I've torn into ground ups on a bunch of machine tools, I'm no expert, and have only done one major rail and screw replacement, but I studied up pretty damn hard.
Good luck.. Quite a project you've got going there. Hope it works out the way you want it too.
Oh there's a mark, i didn't know that, still learning i guess
Thank you mate.
Thank you, ill read over again what you guys wrote. Got to go, thanks guys
Yes the rails have an edge on the CNC chassis to butt against
Hiwin should have technical installation information on their website. Look for it. Likely contains useful info relating specifically to their components.
Hey guys, I can't actually find an M for master on the rails
I think ill end up getting a technician in to do it for me, that's what Im thinking anyway but so close to Christmas it will be in the new year.
Anyhow i have positioned the rails and bearing with the arrows pointing towards the shoulder of the chassis.
Also a pic of me pointing at the adjustment/alignment screw.
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Tell that to the Swiss and Germans. I have refitted rails to slideways that the gap was filled with turcite epoxy after alignment. Not on, but as an abutment edge.
If you don't know something, don't embarrass yourself by making statements that aren't true.
It's a common practice and obviates the need to grind a safe edge.
If you don't believe me, a service engineer on 5 axis Swiss / German CNC mill centers, a graduate engineer with 40 years in the machine tool industry, do your research.
No, there is not always a fiscal Master Rail, the only time you refer to a Master Rail is that sometimes there is only (1) shoulder the rail is clamped against, this is then the Master Rail or main reference rail, if you have (2) shoulders then you can just pick (1) of them as the master and indicate the other too it.
Mactec54