HL1 Counterbalance Spring Broke

[Geof]

Anyone else had the spring that counterbalances the X axis on the HL1 break?

We have a ten years old HL1 Big Bore that has done quite a bit of work, something like 580,000 tool changes. Today the spring broke with quite a bang. The break is in the middle and the top half of the spring rebounded and bent the 3/8" bolt that I think must have been intended to act as a keeper on the spring mount then bent the enclosure.

Now I guess my problem is figuring out how to stretch the replacement spring to install it when we get it delivered.

Incidentally if this ever happens to you don't hit Estop, hit feedhold. I was near the machine and hit Estop when I heard the bang. This turned off the servo power and the X axis dropped down to maximum travel. Fortunately the turret was clear of the chuck and part so nothing happened.

[Geof]

The local Haas dealer had a spring in stock which is pretty good for a ten years old machine.

Now I am an expert on installing and tensioning a 4" coil diameter extension spring using around 3/8" wire diameter, from an unloaded length of about 12 inches out to almost 20 inches. That thing is strong!!!

[SE Plastics]

I had to do mine last year on a SL-20. I don't remember it being too bad a job, seems like it was about 1/2 day to break the machine down, replace the spring, and then put it all back together. You're right, it makes quite a bank when it goes!