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Help with replacing drawbar and belville springs on a Fadal

D. Rey

Titanium
Joined
Jan 20, 2003
Location
Phoenix, AZ
I have the maint manual but they only have a description of the procedure. Having never done this before, and not really knowing what they mean by "remove the drawbar assembly" I was wandering if anyone has done this?

At the top of the head I see the plate, with a shaft and spring over it, under that is the drive belt. Is that spring the one that gets replaced?

My rebuild kit with a new drawbar and balls, springs comes in Wed.
 
We did this to a Hurco. If your Fadal has indeed Belville springs, they look like a stack of washers. The spring you are referring to, is it coil or belville? If it's Belville good chance that's it. If you remove these and your manual is not explicit, PAY ATTENTION TO HOW THEY ARE ARRANGED. You must duplicate this stack arrangement,I.E. 4 cupped up,4 cupped down etc. BTW: McMaster Carr sells exact Belville springs for Hurco, perhaps Fadal as well.
 
Oh Boy! Yep, I've had to replace the drawbar and bellville washers on a couple of the FADALs. The entire orientation bridge must be removed. Before removing anything, push the TOOL LOAD/UNLOAD button a few times and notice what is happening. A plunger is pressing down on the top of the drawbar. That is the area you need to be workin on. We made a couple of items to make the process easier for us. One is a 1/2" rod about 18" long welded to a base. Nothing fancy. The base sits on the table with the rod extended up into the spindle. We jog the "Z" axis down until there is slight pressure on the rod from the draw bar. Then we remove the orientation bridge, that whole contraption where the plunger is. The other part we made is a "pusher". It's a "U" shaped block that fits on top of the drawbar. It has a bolt thu the center and some hold down holes. We mount this on top where the bridge came off and use the bolt to depress the drawbar, essentially collapsing the washers. There are two half-moon keepers that will slide out of the shaft once the washers are depressed. With the keepers out of the way, loosen the bolt on the home made thingy and remove it. As you jog the "Z" axis back up, the drawbar will slide out. Note the orientation of the bellville washers as the must go back in the same sequence.

Without the special gadgets we made, I don't know how you would compress the washers to remove the keepers that hold the whole thing together. I'm sure the FADAL service guys have something. We replace the washers about once every 18 months on all our Fadal's and our maintanence guy can do the whole thing in just over an hour. It's not a bad job once you've done it a few times but you may have some trouble without a means to compress the washers.

While you've got it torn down that far, I would suggest that you replace the washers. We get ours thru MSC and I think it's only like $50 to buy new ones. May save some headaches down the road.

For good technical help call FADAL at 1-818-727-2100. Ask for Neal Debasio. He'll be able to talk you thru it and offer some advise.
 
I did it a couple of months ago, really easy. You do need to make a tool to compress the washers to get the half moon retainers out. Ours was a simple T shaped piece of 1018 that bolted to the three threaded holes up on top with two more bolts to in the T that pushed down on the springs. You do have to remove the big black "piston" that pushes down on the drawbar before you get that far though. Our drawbar was fine and Fadal only wanted to sell us a one piece that didn't use the retainers, so we just made new retainers out of a piece of 13-8 we had kicking around. Another thing that needed replacing, was the piece just up inside of the taper that the bearings on the drawbar slide on to grip the retention nob. After the drawbar is removed, you can pull it out pretty easy, its held in place with two small bearings, which will either pop out if your lucky or you may need to use a magnet if they are stuck a bit. This piece on our machine was screwed, it was only like $21.00 from fadal.

If your tools aren't being pulled up tight into the taper, I would say its either $21.00 dollar part up above or you washers, it doesn't seem like there is too much that can wear on the drawbar.

On our machine, the previous owner didn't replace the bellevill(sp?) washers, he would just take out a couple drop in a spacer and pile the cracked ones back in.

Good luck, its pretty easy once you get in there.
 
So got this rebuild kit, anyone have a pic with some dimensions of this tool I have to make? I only have one mill and if I take it apart to measure for this part I won't have a way to make it. Murphys law states that I will break something as soon as I undo the first bolt so it would be nice to have this tool in hand before I go at 'er with the socket set.
 
Thanks! I have the sheet metal off, I see the drawbar assy, and the orientation bridge, I've read above that all of that needs to come off ...how about the drive belt and pulley?
 
No, the drive belt and pulley does not need to be removed. There are like 6 or 8 bolts that hold the orientation bridge on. remove those bolts, lift the bridge up and let it hang off to the side. No need to disconnect the air lines, ect.

I'll have the maintainence guy get our tools out and I'll try to get some dimensions. May be hard to describe since I don't have a way to post pictures, but I'll try later on today.
 
Bob was kind enough to e mail me pics that explain a lot, and the specs to make my own. I appreciate all the help guys.

Dave
 
Tool changes used to go ku-KLUNK!

Now they go pppssssssssss.

Thanks for your help guys, saved me some dough and learned me something to boot.

Dave
 








 
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