acrylic platter mat
- Thread starter DENNYDOG
- Start date
MWalt
Super Member
That would be a concern, but that motor is a beast. Denny, how heavy do you estimate that the acylic will be?
I honestly believe the best results would be obtained from a custom recessed armboard. Hard to see the recession on the custom technics armboard that is for a Jelco 370, but look at this one:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=150529456120&ssPageName=STRK:MEWAX:IT
DENNYDOG
Addicted Member
I am guessing it will add about 2-3 pounds to the platter. Maybe enough where I will need to help the motor along since it's a belt drive. The motor is very substantial so I don't think it will have any problem once it get's going. It's the starting that it might have the problem with.
The thrust washer was toast. I know others have made them out of delrin but I have some teflon shaft I will make a new washer with. This is probably a slightly better material as Teflon has the lowest coefficient of friction of all known solid materials. This should be a benefit with the additional weight.
The thrust washer was toast. I know others have made them out of delrin but I have some teflon shaft I will make a new washer with. This is probably a slightly better material as Teflon has the lowest coefficient of friction of all known solid materials. This should be a benefit with the additional weight.
DENNYDOG
Addicted Member
Ok I got the arm mounted today and was able to see if my calculations for the thickness of the mat were correct. It looks like I will have plenty of adjustment and the height should be perfect once I get get a stylus mounted on the cartridge.
A few pictures for your pleasure of how the vta works on this arm. It's adjustable on the fly just by turning the black adjustment on the base of the arm. The adjustment for the antiskate (bias) is directly above it.
I will start on the acylic mat this the beginning of this coming week. Hopefully I can finish it before next weekend. I am still waiting for the new belt to arrive.
A few pictures for your pleasure of how the vta works on this arm. It's adjustable on the fly just by turning the black adjustment on the base of the arm. The adjustment for the antiskate (bias) is directly above it.
I will start on the acylic mat this the beginning of this coming week. Hopefully I can finish it before next weekend. I am still waiting for the new belt to arrive.
Don't machine any raised areas duplicating the original raised areas of the rubber PL-41 mat...there's not a single acrylic platter or mat that has that, and for good reason...do a search on why acrylic platters were brought about in the first place...
I you want to kind of mimic the look then I would say machine grooves in the top matching the raised areas of the original mat..but, it would probably be best to just leave it flat...I'd take a very light, fine pitched run across the face of the platter just to take out the gloss surface of the acrylic...
Good luck and keep us posted with pictures!
I'm playing my 41 right now with a Dave Brubeck LP, "Twenty Fifth Anniversary Reunion" and it sounds great!
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I you want to kind of mimic the look then I would say machine grooves in the top matching the raised areas of the original mat..but, it would probably be best to just leave it flat...I'd take a very light, fine pitched run across the face of the platter just to take out the gloss surface of the acrylic...
Good luck and keep us posted with pictures!
I'm playing my 41 right now with a Dave Brubeck LP, "Twenty Fifth Anniversary Reunion" and it sounds great!
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DENNYDOG
Addicted Member
Sounds good Rick. I wasn't sure if I should or not. I do have enough to do two so maybe I will try it just for the hell of it and see if it sounds any different. I haven't really done much research into the acrylic mats. Do you know of any good links off hand?
I tried the dustcover and even at the lowest setting it just hits. It looks like the original was fabricated so it wouldn't be that hard to make one that's a little taller that looks like the original. I had measured it before and it looked like I had about a 1/2" to work with so I don't know where I went wrong there. No big deal I guess.
I will post more pics this week. It shouldn't take that long to make the mat if I don't machine any grooves into it other than clearance for the label. I wonder how they get the frosted appearance to all the mats I've seen? Walnut shell or glass bead I presume?
I tried the dustcover and even at the lowest setting it just hits. It looks like the original was fabricated so it wouldn't be that hard to make one that's a little taller that looks like the original. I had measured it before and it looked like I had about a 1/2" to work with so I don't know where I went wrong there. No big deal I guess.
I will post more pics this week. It shouldn't take that long to make the mat if I don't machine any grooves into it other than clearance for the label. I wonder how they get the frosted appearance to all the mats I've seen? Walnut shell or glass bead I presume?
ripblade
Addicted Member
The acrylic mat on my Oracle has a slight concavity that ensures the edge of the Lp makes contact when the clamp is tightened. This concavity is not obvious without a straight edge, and is roughly 1/2 to 1 mm deep overall.
Worth considering while you have the slab on the lathe.
Worth considering while you have the slab on the lathe.
DENNYDOG
Addicted Member
I got my first rendition of the acrylic mat made. I am going to make another as this one didn't quite turn out to my satisfaction and ended up being slightly too thin. I think the next one I will leave at the 3/4" thickness instead of trying to machine the face. I have the stock mat on it right now to bring it up to the height that I need.
It was difficult getting the correct speed and feed rate and as a result I ended up machining too much off. I think the next one I will just machine the edge and then blast it to give it the texture I want. I will still end up cutting a depression for the label in the center.
Otherwise I am quite happy with how it turned out. It seems to work and sound great. I don't really have a baseline to go by as I never listened to the stock arm or table but sounds every bit as good as my stock PL-61.
I still need to do something about adding length to the spindle. I have some stainless shaft ordered so I may still fabricate one. It doesn't look like there is a lot of room for a small stub shaft pressed into the acrylic. We will see once I get the next one made.
It was difficult getting the correct speed and feed rate and as a result I ended up machining too much off. I think the next one I will just machine the edge and then blast it to give it the texture I want. I will still end up cutting a depression for the label in the center.
Otherwise I am quite happy with how it turned out. It seems to work and sound great. I don't really have a baseline to go by as I never listened to the stock arm or table but sounds every bit as good as my stock PL-61.
I still need to do something about adding length to the spindle. I have some stainless shaft ordered so I may still fabricate one. It doesn't look like there is a lot of room for a small stub shaft pressed into the acrylic. We will see once I get the next one made.
voltcontrol
Fizheuer Zieheuer
This looks great!
DENNYDOG
Addicted Member
Thanks guys! I was a little dissapointed in the finish of the inside groove where it didn't cut that great. This one ended up measuring about 5/8" thick. That's about an 1/8" too thin as when I use the original platter mat it comes out at about the right height that I need.
I didn't plan on maching it down quite that much but like I said I had a few problems trying to get it to cut decent with the tooling I had. I thought I had a little more room to play with. I may ad some sorbothane or something similar in-between the acrylic and platter. This will make it a little easier to cut the thin narrow groove on the bottom as it won't have to be quite as deep.
It will be interesting to see how the black looks underneath. I like the way it looks now being able to see the aluminum through it.
I didn't plan on maching it down quite that much but like I said I had a few problems trying to get it to cut decent with the tooling I had. I thought I had a little more room to play with. I may ad some sorbothane or something similar in-between the acrylic and platter. This will make it a little easier to cut the thin narrow groove on the bottom as it won't have to be quite as deep.
It will be interesting to see how the black looks underneath. I like the way it looks now being able to see the aluminum through it.
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DENNYDOG
Addicted Member
I made some very good progress this week and was able to finish turning the last two of my acylic platters. I decided to do these at the same time in case I screwed one of them up like I did on the first one.
I left this one at 3/4" and didn't mill the top or the bottom surfaces. I chamfered about a 1/16" relief for the record label and chamfered the outer edge about a 1/4 x 1/8". I think this looks a lot better and gives a slight relief for the run-in groove. I had to make a special tool for turning the groove on the underside of the platter for the lip on top inside edge of the platter.
I am very happy with how everything turned out. I was thinking about blasting it to give it the satin finish you see on most acrylic platters but I think I like it the way it is. I may experiment on the first one and see how it looks and then decide from there if I want to do it to this one.
The only other thing left is the centering spindle for the record. I ordered stainless round to make a longer spindle but I am thinking of getting some acrylic round and gluing it into the top of the platter. There is about a 1/4" or room from the top of the platter to the top of the spindle. That should be plenty of room to glue a short stub for centering the records on.
I think it actually sounds better now than the first platter I tried with the rubber mat. I can definitely turn it up more now before I get feedback from the speakers. The music seems to have better clarity to it also than before. The only other thing is to make a new thrust washer. I had some teflon round around here somewhere that I had ordered for my PL-61 but couldn't find it. This one is slightly larger so I ordered a new piece. This should bring the whole platter up some more as it's riding a little low from the bad original thrust washer.
I have to say I'm VERY happy with the results. If anyone is up in the air about what kind of platter mat to try I would definitely recommend trying an acylic mat. I can't guarantee that you will get the same results but it's worth a try. And here are a few pictures for your enjoyment.
I left this one at 3/4" and didn't mill the top or the bottom surfaces. I chamfered about a 1/16" relief for the record label and chamfered the outer edge about a 1/4 x 1/8". I think this looks a lot better and gives a slight relief for the run-in groove. I had to make a special tool for turning the groove on the underside of the platter for the lip on top inside edge of the platter.
I am very happy with how everything turned out. I was thinking about blasting it to give it the satin finish you see on most acrylic platters but I think I like it the way it is. I may experiment on the first one and see how it looks and then decide from there if I want to do it to this one.
The only other thing left is the centering spindle for the record. I ordered stainless round to make a longer spindle but I am thinking of getting some acrylic round and gluing it into the top of the platter. There is about a 1/4" or room from the top of the platter to the top of the spindle. That should be plenty of room to glue a short stub for centering the records on.
I think it actually sounds better now than the first platter I tried with the rubber mat. I can definitely turn it up more now before I get feedback from the speakers. The music seems to have better clarity to it also than before. The only other thing is to make a new thrust washer. I had some teflon round around here somewhere that I had ordered for my PL-61 but couldn't find it. This one is slightly larger so I ordered a new piece. This should bring the whole platter up some more as it's riding a little low from the bad original thrust washer.
I have to say I'm VERY happy with the results. If anyone is up in the air about what kind of platter mat to try I would definitely recommend trying an acylic mat. I can't guarantee that you will get the same results but it's worth a try. And here are a few pictures for your enjoyment.
voltcontrol
Fizheuer Zieheuer
A work of art Dennydog!
MWalt
Super Member
I think AK member Finnbow has some delrin thrustwashers that he is selling. Contact him. I have one on my PL-41 and it works great.
