acrylic platter mat

[sxty8goats]

Sorry I'm getting in here a bit late.

If you want to improve surface finish with hard plastics, use a cutter with a radius on the corners of the cutting edge. Sharp corners will cause taring. You can use off the shelf cutters, just use a stone to round out the corners. The cutting edge should be sharp, Think of a ball end mill vs a standard end mill. The ball is a radius with a sharp cutting edge. Create the same sort of thing on your cutter, It can be .010" as long as the edge isn't coming to a point, your finish will improve.

Also use high speed steel cutters. For some reason I've had much greater success with HHS over carbide or any other cutter material when cutting plastics.

 

[DENNYDOG]

Perhaps because I didn't read every post in this entire thread but I missed how you plan to make the spindle protrude up through the thick mat?

I bought some stainless shaft that I planned on turning down to make a longer spindle. I might go the easy rought and just glue a short length of acrylic round to the top portion of the spindle hole. I have a good 1/4" as the spindle doesn't go all the way to the top of the platter

Sorry I'm getting in here a bit late.

If you want to improve surface finish with hard plastics, use a cutter with a radius on the corners of the cutting edge. Sharp corners will cause taring. You can use off the shelf cutters, just use a stone to round out the corners. The cutting edge should be sharp, Think of a ball end mill vs a standard end mill. The ball is a radius with a sharp cutting edge. Create the same sort of thing on your cutter, It can be .010" as long as the edge isn't coming to a point, your finish will improve.

Also use high speed steel cutters. For some reason I've had much greater success with HHS over carbide or any other cutter material when cutting plastics.

Thank you for the tips. I believe it was a carbide tip I was using. I'm no machinist by any means and we do more welding in our shop than anything else. It's an old worn out Osama lathe that we got a few years back.

 

[pioneervato]

Impressive work, DD! Very nice!

 

[ripblade]

Very nice work DennyDog. One word of caution before you cut your next mat: As one who has played his records with an acrylic mat for over 20 years, I suggest you make the top outer corner with a diameter of 293mm exactly. The reason being that this is where the outer edge of the record will contact the mat. You want this point to rest squarely at the lead in groove. I know this because the mat I have is slightly smaller, and some of the records I've played on it over the years have an accumulation of clicks and pops just after the music begins.

In light of this, I also strongly suggest you keep the mat meticulously clean (I clean mine with a Nagaoka roller before each play as a result of this experience) as any dust at the contact points between mat and record will surely be wedged into the groove.

For the effort, the sonic result is worth it, as you've already observed.

Happy listening,
Glenn

 

[sxty8goats]

Thank you for the tips. I believe it was a carbide tip I was using. I'm no machinist by any means and we do more welding in our shop than anything else. It's an old worn out Osama lathe that we got a few years back.

Anytime. Most lathe 'inserts' type tools are ceramic. Not very good for plastic. If you have standard type tool holder but no high speed steel to make a cutter out of, you can use a drill bit and grind it down. When I was in the shop a lot, I kept a couple of HHS chunks in my tool box for plastic. For some reason, it can be hard to come by in machine shops sometimes. Apart from drill bits, most lathe tooling tends to be ceramic or carbide.