Author Topic: Never thought I'd see this.  (Read 2754 times)

Offline DavidA

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Never thought I'd see this.
« on: December 27, 2021, 04:24:21 PM »
As some may know I have a Seig Mini Mill. The X1L (long bed).

I don't particularly like this machine, but can't really afford anything else at the moment.

But it suffers from a lot of vibration. And I tracked it down to the motor pinion. It is hard to describe just how loose it is on the shaft.
So I decided to get another pinion gear, maybe two , and looked it up.
It's described as a 'sacrificial motor gear pinion' Or something very close to that.

I mean, 'sacrificial', how bad does a design have to be for the part to be describe like that ?

Offline awemawson

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Re: Never thought I'd see this.
« Reply #1 on: December 27, 2021, 05:10:53 PM »
Often a gear made from a weaker material is introduced into a machines drive chain as a ‘mechanical fuse’ so that a relatively cheap and easy to change gear is the weakest link in the case of a jam up.

Similar concept to a shear pin.
Andrew Mawson
East Sussex

Offline DavidA

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Re: Never thought I'd see this.
« Reply #2 on: December 28, 2021, 11:53:25 AM »
I can see that would work. But it is so loose it is really as suicidal gear. Will possible take out it's mating gear when it fails.

I'm thinking about doing a belt conversion.

I notice that people seem to use 'V' belts. But considering the comparative stiffness of these, would it not be better to use a toothed timing type belt ? They are thinner an more flexible. Possibly more suitable for the size of the motor pinion.

Offline drmico60

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Re: Never thought I'd see this.
« Reply #3 on: December 28, 2021, 05:48:54 PM »
As some may know I have a Seig Mini Mill. The X1L (long bed).

I don't particularly like this machine, but can't really afford anything else at the moment.

But it suffers from a lot of vibration. And I tracked it down to the motor pinion. It is hard to describe just how loose it is on the shaft.
So I decided to get another pinion gear, maybe two , and looked it up.
It's described as a 'sacrificial motor gear pinion' Or something very close to that.
I mean, 'sacrificial', how bad does a design have to be for the part to be describe like that ?

I also have a Sieg X1L mill. It was very noisy when I first had it and it would also trip the controller or blow the fuse if the going became difficult. I replaced the gear drive from the motor with a belt drive, see:
http://mikesworkshop.weebly.com/mill-belt-drive-conversion.html
After the mod it was like a different machine. It was quiet and the controller very rarely trips and no fuses have blown. I think the latter two effects result from the belt being slightly stretchy and the belt can also slip a little. This insulates the motor and controller from sudden shock loading when machining.
Mike

Offline chipenter

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Re: Never thought I'd see this.
« Reply #4 on: December 29, 2021, 03:01:46 AM »
Mine rattled and the key is small so the key ate the inside of the gear , my solution was to bore the gear and fit a knurled brass centre , the knurling made the diameter of the brass slightly larger and stretched the gear which gave it a better mesh and much quieter .
Jeff

Offline DavidA

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Re: Never thought I'd see this.
« Reply #5 on: January 04, 2022, 11:27:24 AM »
Thanks for both replies.

I think I will go for Mike's belt solution. The gear pinion set up just looks too flimsy over all. But  I never liked plastic gears.