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 Post subject: Re: need help with Facetron
PostPosted: Mon Jan 14, 2019 6:09 pm 
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Joined: Thu May 12, 2016 2:18 am
Posts: 1542
As Jeff at Jarvi has said, the issue is most likely one of technique rather than the machine.

One issue is that when you cut to zero against the hard stop and you apressing on the quill, you actually will get flex in the machine. All machines will flex. When trying to cut to "numbers" I use a soft stop technique where I put all of the pressure on the stone, not on the quill. I also use one small mark on the dial before zero as my target rather than zero. This will keep me off the hard stop, and avoid flex.

Conceptually one of the biggest mistakes people make is try to use the dial indicator to set the angle. Instead look at it as a measuring device. Since it is a measuring device you need to eliminate as many variables as possible. This means that as you approach your finished mark you make sure you are only cutting on a small spot on the wheel. Jeff says that about a postage stamp size is best. I have found this to be true.

I have found with all machines I have ever used that you will end up having to look and walk the facet in to get perfect meets. Cutting perfect meets by the numbers is just not reality.

So, it is all about developing a feel and a technique. Once you have this down, you will find that the Facetron is a fast, accurate, and repeatable machine.

If I could spend just a couple of hours with you in person I could save you tons of frustration on the learning curve.

Steve


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 Post subject: Re: need help with Facetron
PostPosted: Mon Jan 14, 2019 9:49 pm 
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Joined: Tue Jan 02, 2018 11:12 pm
Posts: 206
1bwana1 wrote:
As Jeff at Jarvi has said, the issue is most likely one of technique rather than the machine.

One issue is that when you cut to zero against the hard stop and you apressing on the quill, you actually will get flex in the machine. All machines will flex. When trying to cut to "numbers" I use a soft stop technique where I put all of the pressure on the stone, not on the quill. I also use one small mark on the dial before zero as my target rather than zero. This will keep me off the hard stop, and avoid flex.

Conceptually one of the biggest mistakes people make is try to use the dial indicator to set the angle. Instead look at it as a measuring device. Since it is a measuring device you need to eliminate as many variables as possible. This means that as you approach your finished mark you make sure you are only cutting on a small spot on the wheel. Jeff says that about a postage stamp size is best. I have found this to be true.

I have found with all machines I have ever used that you will end up having to look and walk the facet in to get perfect meets. Cutting perfect meets by the numbers is just not reality.

So, it is all about developing a feel and a technique. Once you have this down, you will find that the Facetron is a fast, accurate, and repeatable machine.

If I could spend just a couple of hours with you in person I could save you tons of frustration on the learning curve.

Steve


I tend to agree, and about the frustration part for sure... it took me about 7h just to figure out where is the problem.
Starting from checking the level of the lap and than to the micro level height adjustment ,to disassembled everything on the machine to parts,and to the level of the spring and the gears inside the indicator -they was out. it was a long day. :roll:
its now all back to where it was when i bought the machine, [-o< and i am sure not going to use this hard stop again.
the 0 for me is now way back from where i set the hard stop.
when roughing, i am just cutting till it reach almost to the 0 (or any other given number that i choose as my target point as it doesn't really matter) then,when i am about half inch from it- i stop, and than reach the meets by look and cut slowly.
depends also on many factors. the speed and the lap material and material itself of course,but when cutting at slow speed on fine grit,usually i don't need to look that much really, cuse the needle is almost not jumping forth and back, and the machine is accurate,as you said.
developing a feel and a technique (and one that work best for the persona) is the most important in any field,regardless of the equipment been used.


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 Post subject: Re: need help with Facetron
PostPosted: Tue Jan 15, 2019 2:27 pm 
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Joined: Sat Apr 24, 2010 7:10 am
Posts: 584
when the height is locked down the facet head pivots on a ball bearing...if it is missing it can cause that problem of the height readjusting itself as you swing back and forth...if it isn't missing try this.

as you approach zero back off on the pressure you exert on the stone and do this at the same radius on the lap each time closer to the center is better. 1/4 oz of weight bearing down on the stone and repeat for a series of facets that meet at the same point...if it still a problem i dont know anymore


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 Post subject: Re: need help with Facetron
PostPosted: Fri Apr 23, 2021 10:37 pm 
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Joined: Fri Apr 23, 2021 6:32 am
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Location: Tasmania Australia
An old thread, but still relevant, plus some Facetron internal views for the record.

I had until recently exactly the same problem as the original poster with my ~ 2018 model Facetron from new. I learnt to work around the annoyance, and did so for three years. For me, the problem was the lever return spring, it was too short, and perhaps also needed to be a little stiffer in compressive nature. I replaced the standard spring with another about 5mm longer (quarter of an inch) than the original.

Open up the back plate, you can just make out the little lever in the hole (zoomed in next photo):
Attachment:
File comment: Opening the Facetron back plate
on_open.jpg
on_open.jpg [ 303.71 KiB | Viewed 860 times ]


Closer look at area of interest:
Attachment:
File comment: hard-stop/soft-stop components and mechanism
hard_stop_components.jpg
hard_stop_components.jpg [ 302 KiB | Viewed 860 times ]


Close-up of internal mechanism of Facetron (with dial indicator):
Attachment:
File comment: Brass gear and toothed bar
brass_gear.jpg
brass_gear.jpg [ 288.73 KiB | Viewed 860 times ]


The small and gentle movements of the gear mechanism that occur whilst cutting transfer to the dial indicator fine if the return spring is long and strong enough to properly hold the toothed bar to the brass gear (see below). The return force present in the dial indicator was insufficient on its own (in my machine) to fully transmit the cutting movements to the dial needle in all situations.

More info available at: https://aussielapidaryforum.com/forum/index.php?topic=6824

RC


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