Thanks for your offer. I found one more dealer and think I will get 2 new tries. This time from Sternglas. If this again not working I really like to choose your offer!
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Project "RWI Raffle Win"... a 1675 Build
- Thread starter p0pperini
- Start date
element79
Active Member
- 18/1/22
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I love reading this thread! Great experiences from all of you and with all this amazing info has made me decide to start my own “little”1675 project. Especially
since the plexi on my BP 1675 case is wrecked so I have to find a new one, and maybe improve some stuff from there to make it better.
Just a question: wouldn’t a Dremel be a tool you could size down the plexiglass with?
I’m actually thinking of buying one for all this sort of stuff, or would you think that’s a bad investment?
since the plexi on my BP 1675 case is wrecked so I have to find a new one, and maybe improve some stuff from there to make it better.
Just a question: wouldn’t a Dremel be a tool you could size down the plexiglass with?
I’m actually thinking of buying one for all this sort of stuff, or would you think that’s a bad investment?
A Dremel will soon become your best friend if you buy it but it's not suitable to reduce plexiglas size unless you create a specific chuck or tool. You will also need to be very careful as sanding away material will heat up the plastic resulting in chances of warping/deforming. In short do it only if you feel really comfortable with your Dremel
element79 As kilo says, a Dremel is a fantastically useful bit of kit, but you have to be careful how you use it. When I use mine on watch cases or parts, I tend to use the quite-cheap-but-very-useful Dremel Workstation 220. It effectively turns your Dremel into a mini pillar drill, and once the Dremel is clamped into it, you then have both hands free to hold the piece being worked on. Those who already have a workshop setup with a clamp can achieve a similar end by simply clamping the Dremel.
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element79
Active Member
- 18/1/22
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kilowattore p0pperini Thx, that's about how I figured it.
Also about striking a balance between sourcing the required parts from the people who know their stuff, and me figuring out how to not screw things up.
In the meantime I'm surely going to p*ss off the wife by installing one of those workbenches in the attic!
Also about striking a balance between sourcing the required parts from the people who know their stuff, and me figuring out how to not screw things up.
In the meantime I'm surely going to p*ss off the wife by installing one of those workbenches in the attic!
hi
As you thin the outer plexi wall down you decrease its deformation resistance, so it will increase in diameter, especially at the lathe jaw contact points. So you may end up with a plexi that will be "out of round" . It is good advice to grip this on a "male mandrel" that will at least allow for a concentrically dimensioned and finished article. It is not good practice to do this by hand as you will NOT get it concentric or with even wall thickness which may affect WR should you need it.
As you have a good lathe this shouldn't be too difficult for you to make the mandrel
Thanks for chipping in Ade. I'll just tag matzemedia to draw his attention to your note - as you quoted me, and he's the guy doing the lathe stuff here.
I can only dream of owning such awesome professional equipment (a dream that would quickly turn to a nightmare, were I ever stupid enough to invest in one, as serious injury and probably death would follow closely thereafter...)
Hi ado213 ,
thanks for your hint about the "male mandrel". You could be right, that I produce a "egg" by using a three-jaw chuck. In the past 3 weeks I cracked more than 6 crystals, but currently its done. I asked several people and learned a lot.
Here some more learnings:
thanks for your hint about the "male mandrel". You could be right, that I produce a "egg" by using a three-jaw chuck. In the past 3 weeks I cracked more than 6 crystals, but currently its done. I asked several people and learned a lot.
Here some more learnings:
- Polywatch contains strong hydrocarbon based chemicals which can weaken the plastic crystal. The Polywatch in contact with the crystal sides, which are under pressure from the retaining ring, maybe weakening the plastic of the crystal. Using toothpaste to polish is maybe the better way.
- Using toothpaste for polish is not as good as Polywatch. I tried 3 different toothpaste - at the end it is still matt.
- Polishing with a dremel produce a lot of heat at the crystal. So you run the risk of melting plexigas.
- By using a file you can give it a bit of an angle to it's smaller at the top and more on the bottom as you only need a pressure point as wide as the ring
- The 1680 case has a smaller pressure ring and it much easier to press the crystal.
You are indeed correct with your findings, toothpaste is not ideal, polywatch is far better, dremel is a no-no on plexi, that is unles you allow it to cool between polishes, but still a very dangerous, they do not like heat !!
Make your mandrel a "press fit" and take very small amounts off with your tool, be patient. You can also set your compound slide on your lathe at a slight angle to give you the same amount of taper as you have filed previous versions. you do have another option, which is to bore the crystal retainer
Make your mandrel a "press fit" and take very small amounts off with your tool, be patient. You can also set your compound slide on your lathe at a slight angle to give you the same amount of taper as you have filed previous versions. you do have another option, which is to bore the crystal retainer
Now that sounds like my kind of task. My treatise on "The complete history of how our local roundabout's traffic light system has been totally ballsed up by whoever is in charge of it" runs to about half an hour and should do the trick.
