Presto Pirouette T18 - Drive-Line Redesign - Soapstone Plinth - w/ Pics (lots)

Discussion in 'Turntables' started by mfrench, Jul 8, 2011.

  1. mfrench

    mfrench AK Subscriber Subscriber

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    Let me start with this image of the finished TT as a hook; Then, I'll start over with the build from the start.
    [​IMG]
    I've had a few postings about this deck in various threads, here at AK; but I've not started a feature thread about it yet. A few of you Lencophiles have likely already seen this buildup over at LH. There will not be a pop quiz following the presentation.

    So without further adieus and ramblings,....
    This is my Presto Recording Corporation - Pirouette T18DC_mod, c. 1955; reborn 2009/2010; An idler drive TT for the 21st century.

    It started as a 3-speed, three wheel idler drive TT, circa 1955; and is of the last of the true vintage pre-Bogen era Prestos.
    [​IMG]
    It bears the mark of his noodliness, the Flying Spaghetti Monster:
    [​IMG]

    That mark, ^^, made it a holy divine piece, and I endeavored to restore it to its former glory - little did I realize that it was in no mood for any such restoration; It was going to demand a far more intensive effort! It demanded a complete drive-line redesign to drag it out of mid-20th century mono era, and into the second decade of the 21st century.

    The first thing to do was look under the skirt to see what I was in store for.
    [​IMG]
    OK,... So it had three idler wheels,... interesting.
    What drove these wheels?
    The black cube from hell, thats what! I picked up on a nickname from it, coined by another member here, mopic5, as he is involved in a similar deck project, with the same motor. He called it, most appropriately, the Borg Death Cube. The name resonates in infamy.
    [​IMG]
    [​IMG]

    The Borg Death Cube had a three step capstan-pulley that was seized to it, and it took forever to get it freed.
    Well, in dissecting the OE drive-line, I found that the motor mounts were shot, and had been improperly hung, with washers that caused a rigidity of the motor to the top plate, rather than as a suspension as had been designed.

    OK,... So, motor suspension is shot.
    I'd removed and had already sent the idler wheels out to the overhauler, Ed Crockett, for some new tires.
    Lets take the bearing off and clean it; great condition, but with some wear; not egged - solid.
    I lubed the motor, actually drilling out some rivets to open the motor, and deep lube it, regrease the thrust plate, polish the bushings, etc. Problem: there was pitting on the upper motor spindle within the bushing, and matching corrosion in the upper bushing.

    The idler wheels returned, hook it all up and give it a spin,...
    rumble, and lots of noise. Damn.
    So, I take the motor out, and flip the bushings top-to-bottom. This helped, but the damage to the spindle shaft seems to have reduced its diameter to a degree that its sloppy on the top of the bushing.
    I tried every trick in the book to quiet the motor, but, all I could do was reduce the amount of noise, but it was still at an unacceptable level.
    After months of trying to fix the motor, I gave up on it, and, decided to install a new motor into the old original three-wheel driveline.
    So, I started shopping out motors and had a hankering to build it with a DC motor, and a precision controller.
    I found a motor, based purely on its size comparison, to ensure that I could fit it into the same space as the original assembly. It was from a local company that designs and builds the controllers here locally, and imports the motors that they re-badge.
    [​IMG]
    [​IMG]
    And it had a matching driver that offered intimate monitoring and control:
    [​IMG]
    The driver has three hall sensors around a 360º circumference. They monitor the speed of the motor, and keep it locked at an unwavering dead-to-speed locked RPM. It does not slightly wander off speed. I can carry speeds from a zero-stop to hundreds of RPM at the platter.

    A new motor mounting plate is built, and new motor mount suspension grommets are installed at each point.
    [​IMG]
    [​IMG]

    A new mounting achieved:
    [​IMG]
    [​IMG]
    [​IMG]

    New stainless steel vs. old mount:
    [​IMG]

    OK,... So, new high tech motor and mount finished; Check, test.
    Result: Newly realized driveline noise; AND, worse -- A realization that the original geometry of the three wheel design favored the newly developed 33 and 45rpm speeds, and only included the 78rpm speed as a nice added speed, as it was still so close to that era. The deck was fundamentally flawed and noisy if you tried to adjust the motor tensioning to accommodate all three speeds in a single adjustment.
    The design is best described as a power take up from a rotating platter and its interface with the wheels and capstan. The power uptake regime was designed to transfer the capstan -> wheel -> platter at approximately two positions; 5 o'clock and 7 o'clock, with a crucial center point line being marked by the 6 o'clock to 12 o'clock center line, from bearing to capstan. Look at the image above, and mentally draw a line between the bearing center and the 33prm graphic on the top plate, with the bottom of that line being 6 o'clock.
    The 33/45 rpm speeds power take-up were on the 5 o'clock side of the 6 o'clock line, and the 78 rpm wheel was at the 7 o'clock mark - you can see that in the last image, above.
    At the 5 o'clock position, the wheels are captured by the downhill motion of the platter, and driven into the capstan, in an ideal, forced-into-compliance motion. The 78rpm wheel, however, was on the uphill swing of the platter, past 6 o'clock, and, the only way to properly engage that wheel was to adjust for it; But by adjusting for it, 33 and 45 rpms became noisy. A vicious cycle ensued.
    By adjusting to 33/45, you barely engaged the 78 wheel. Ideally it would need a spring to engage the 78rpm wheel, but its design precluded any spring, as such force would only pull the wheel further away. Believe me, I looked at many options.
    Presto designed this deck with two wheels too many.
    The drive-line is flawed in that regard, and it wasn't until I'd dropped a few hundred dollars into the project that I realized the flaw; it was too deeply buried to be able to detect in the early stages. It would be a decent enough 33/45 deck, or a fine 78rpm deck; just not a universal three speed deck.

    So, now I have to answer to Sarge about why this project has stalled, despite spending like a drunken sailor up to this point.

    Its probably time for a break about now,....

    [/page one]
     
    Last edited: Nov 8, 2017
  2. mfrench

    mfrench AK Subscriber Subscriber

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    We're back.
    So,... I look at the Presto design, and start thinking about throwing a ton more time at it - far more than you could possibly imagine.
    Why not completely redesign the entire driveline? Seriously?
    I mean I've got the motor, and driver now, WTF am I going to do with those?
    Redesign it is.

    So, I look at the design, and see some square inches below the platter, between the bearing and the inner platter rim; its open area there, with a couple of inches below the platter for vertical adjustments. I can just abandon all the new wheels that I have just retread, get rid of the OE motor and capstan, and just redesign the whole dang thing. I've got a whole 12 square inches, and never designed a TT driveline - go for it!

    So, at this point in time, I start hanging out with a bunch of derelict Lenco tweakers, as their red-headed step-cousin from the Presto side of the family. I became intrigued and liked the design of the Lenco idler wheel, and decided to incorporate it into the design. Its tall profile, and skinny knife-edge make a much better idler wheel design than the fat dragster tires of most American broadcast table idlers; 1/4" dragster slicks vs. knife edge.
    The Lenco idler wheel was the idler wheel of choice.

    This is my mating of an original Lenco idler axle, mated to a piece of brass rod stock via soldering. The new wheel axle is to be oriented vertically, with the wheel rotating horizontally, driving the inside of the platter rim; to maintain original top plate lines (no external motor/wheel).
    [​IMG]

    Back to this original picture,...
    The area "above" the bearing is open space that is still below/within the platter overhang.
    Its this area that I proposed to stuff a new drive-line into.
    [​IMG]

    In the end, i also needed to develop a plinth to know if it were to work. So a plywood mockup was constructed. I rigged up a few toe-nailed templates, jigs, and found that it was plausible that this would fit.
    So, while still developing the basics of the new driveline, I started building the plinth for it as well. This one was going to be of soapstone, my first effort in soapstone. Why not breach more new ground in this process?
    A remnant slab is procured:
    [​IMG]
    Cutting underway, and the first motor mount fitting:
    [​IMG]

    First fitting of top plate and new driveline mechanism:
    [​IMG]

    You can see the apprx. platter radius, traced in pencil - This is still early dry-fitting:
    [​IMG]
    New idler arm pivot and wheel orientation with old capstan as a stand-in dummy. A new custom capstan was to be built.:
    [​IMG]

    The platter fits, and the new drive-line mechanism fits below it:
    [​IMG]

    OK,... time for another break,...

    up next:
    the motor mount, and vibration isolating suspension.

    [/page two]
     
    Last edited: Nov 8, 2017
  3. mfrench

    mfrench AK Subscriber Subscriber

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    We're back, again.

    The motor mount, drive-line mechanism; an in-depth study in DIY'ing a TT drive-line,...

    The motor plate suspension struts:
    [​IMG]

    These struts are K&S Engineering precision brass tubing, brass screws, nylon spacers and washers, and Lenco motor springs.
    The nylon washers offer a nearly friction-free motion on the precision brass tubing, allowing the motor springs to freely absorb excess energy that escapes past the rubber motor mounting grommets.

    Struts, whole assembly, and exploded:
    [​IMG]

    struts side profile, motor mount plate added:
    [​IMG]

    motor mount assembly, from a higher profile:
    [​IMG]

    motor mount assembly, mounted to finished CLD base plate. The motor is no longer attached to the plinth or to the top plate. Its now mounted to a suspended base plate that is attached to the plinth from below, by four rubber well nuts. This is to isolate the motor from the plinth, for vibration damping.
    [​IMG]

    The CLD base is, as follows, top-to-bottom:
    ~ 2mm EPDM rubber pond liner adhesive repair tape
    ~ two layers of 1/8" masonite, 1/4" layer
    ~ epdm rubber pond liner
    ~ cork
    ~ 1/2" MDF middle layer
    ~ cork
    ~ rubber
    ~ 1/8" masonite
    ~ 1/2" polyethylene plastic base (black bottom layer - first of two)

    The motor CLD, motor, and driver, mounted to the CLD base:
    [​IMG]
    [​IMG]

    This is the bottom of the deck, with the second polyethylene layer, the finished cover, in place. It covers the motor mounting layer, and conceals the bearing and wiring loom. The motor bottom end is cut through for ventilation into the plinth. It is not viewable when viewing the plinth on a table.:
    [​IMG]

    Plinth construction; laminating the facade edges around the bottom of the main deck. THis was all done at the same time as the driveline mechanism design; days spent on plinth, evenings on the mount.:
    [​IMG]
    [​IMG]

    time for another break,...

    up next:
    the final fittings and design tweaks,...

    [/end page three]
     
    Last edited: Nov 8, 2017
  4. mfrench

    mfrench AK Subscriber Subscriber

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    We're back, again,...

    I decided to abandon the second layer, the armboard of this design, as the deck was becoming unmovable with the load of the motor mount CLD base.
    So, I'd already cut the top deck of the plinth, with the notion that the armboard would cover the motor mount cut-out. I had to cover that hole, and, as a bonus, I wanted to create a better shielding of the motor from the cartridge pickup. So I got some 1/4" aluminum plate, and cut a shield that profiled the deck, and platter. The only point that it came wider than the top plate/platter profile was to cover the motor mount hole, and I brought the shielding in to a minimized cut-out, to maximize the shielding.
    [​IMG]

    The new profile with the fitted shield:
    [​IMG]

    Side profile of new motor mount, new painted shield, and new custom capstan, hour-glass cut to profile the platter - its that tight under there!
    [​IMG]

    Back under the skirt for a bit:

    This is the bearing for the platter. I've braced it in two directions. There is an o-ring of aluminum that pulls the top plate and bearing housing down onto the stone top deck. There is also an aluminum bar that carries the end of the bearing housing, and secures the end cap, in an upward force. The o-ring pulls down, the bar pushes up.
    [​IMG]
    [​IMG]

    Plinth, exploded view. The motor CLD base fits below the top deck. Armboards bolt to the top deck.
    [​IMG]

    Top plate and shield mounted to top deck:
    [​IMG]

    Armboard routing detail:
    [​IMG]
    [​IMG]

    Rear of deck, unfinished, with driver and speed control pot shown:
    [​IMG]
    [​IMG]

    Rear of deck, finished:
    [​IMG]
    You can see the finished armboard on the left. The blue connector is a Neutrik SpeakOn connector, capable of 250vdc and 50 amps. Its a solid twist-lock connector.

    Its first spinning of a stereo record. it was originally built during, and rigged for monaural. It wasn't until my effort that it became a stereo deck.
    [​IMG]

    **The only post-redesign drive-line modification that I've done was to take the motor CLD plate off, dismount the motor, and reverse the wheel take-up side, by turning the motor mount plate 180º. The original mounting side was somewhat particular, and lacked torque.
    By swapping the take-up location from 10 o'clock, to two o'clock, I upped the torque by multiple-fold, two or three times the torque. In fact, it now has so much torque, that it grabbed, twisted and bruised a finger, causing stiffness and swelling - this deck is a torque monster.
    **UPDATE #1: I added a diy'd hardened steel thrust plate (from a construction knife blade) to the platter spindle bearing for a major upgrade, and added depth of blackness.
    *** UPDATE #2: I replaced the spindle bearing bushing sleeves with new ones, 2011-08-09


    I've since changed the modern Jelco arm out. I built a DIY unipivot tonearm that I call the RatsPaw. I started a feature thread about that arm here at AK, several weeks ago. I also began experimenting with stacked platters with this deck. I'm using a platter from a recent Bogen project, but intend to replace it with a 1.5" thick piece of Delrin/Acetal, as a platter extension, in future times.
    This is the Presto deck, with stacked platters, with the RatsPaw mounted to it:
    [​IMG]
    [​IMG]

    I call her: Presto Pirouette T18DC_mod, an idler drive for the 21st century.
     
    Last edited: Nov 8, 2017
  5. Balifly

    Balifly Listening Subscriber

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    A complete graduate course !!!

    :ntwrthy: :ntwrthy: :ntwrthy:
     
  6. Redboy

    Redboy a few good watts Subscriber

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    Uber cool. Another mfrench masterpiece.

    I love your upgrade over the Death Cube.
     
  7. fiddlefye

    fiddlefye AK Subscriber Subscriber

    Astounding! They needed you around when they designed the thing in the first place!
     
  8. Urchinn

    Urchinn AK Subscriber Subscriber

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    You talented devil! Fantastic...
     
  9. mfrench

    mfrench AK Subscriber Subscriber

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    I like to take allot of pictures with this new fangled digital camera thing.
    But seriously, it helps me in having to keep from taking it all the way apart, or, as reference to just how deep I have to dig, should I ever have to fix it.
    Many thanks for the reply.

    A pile of stone rubble remnants that some might think of as art, I suppose.
    You're too kind, Nate. I do appreciate it, though!

    I'm totally fascinated by these old spinners. I just hope that "they", the original designers, could appreciate my concepts, and applications.
    thanks!

    This was such an in-depth learning experience, its impossible to express just how much I learned in building it. I feel that I might have developed a little bit of experience in the effort, but came into it not knowing much about anything that I was doing - just practical DIY experiences from life, all combined in miniature applications. Talent? Sometimes its better to be lucky than good.
    thanks for the kind words.
     
  10. mfrench

    mfrench AK Subscriber Subscriber

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    To preface this post,... I've been experiencing a developing motor noise, a whirring that is audible in an ambient sense, but not translated to speakers. It was audible from a couple of feet from the deck; buried in the music, but still annoying.

    A new thrust pad made from a construction knife blade. It is .025" thick, or, .64mm thick, and of hardened steel. I took an angle grinder and just kept grinding away until I had a small circular disc. I epoxied it to the original thrust pad with four small dots of JB-Weld epoxy to ensure that it would not become loose and noisy.
    The difference in the way the platter felt was immediate.
    I did this because I've been trying to sort out some motor noise and vibrations. I also removed the set screws from the capstan, as they were contributing to the vibrations substantially. I'd installed two of them, thinking that would be a better balance than just one. So, I shimmed the capstan onto the motor shaft with some thin teflon tape, and the vibrations went away (read: rumble). Now I just have an apparent motor noise, a whirring, that is only audible in an ambient sense, and does not translate to speakers; a minor annoyance, but still something that I'm trying to work through without buying a new motor (not really expensive, around $65, but still,...)
    Though not apparent in the picture, the new thrust plate sits on a raised pad (the old thrust point), that is the same diameter as the new plate, so its obscured.

    At any rate, the new thrust pad, and raw materials:
    [​IMG]

    Result:
    WOW! *I spun this up to really high-speed for quite a while yesterday (15 minutes at 200ish rpm platter speed), and then let it run at normal speed overnight - motor noise gone. Platter rotation is smooth as silk. Major upgrade! I'm really blown away, actually, and thrilled with the results.
    I wonder if this deck had been missing some sort of thrust pad all along, or if the original design had intended to have the ball turning on the brass/bronze end? The ball, it seems, had finally dug in deeply enough into the original thrust pad that it was causing the motor to go noisy. Such an easy solve for such an aggravating problem! (it seems,... keeps fingers crossed)
     
    Last edited: Nov 8, 2017
  11. mfrench

    mfrench AK Subscriber Subscriber

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    OK,... I fitted new spindle bearing bushing sleeves today.
    On a whim, I was over at Lowes, and mosied on over to the hardware section, where I found sintered bronze bushings of the proper inner and outer diameter, 1/2"o.d. x 5/8"o.d., but they were too long at 1 1/8". I needed two at 3/4" if I were to match the "originals".
    I wanted to make the top bushing longer than original for better support for my stacked platter finish to this deck, as the top bushing had a devloping case of lateralis; so i wanted to gain more support on the upper bushing.
    So, I bought them in hopes that I could cut one of them down.
    I was able to cut the bushing with an angle grinder and cut-off blade, perfectly, without burning the bushing.
    I pressed the old ones out using a vise in my garage, with a slightly smaller ratchet socket. I backed the bearing housing with a piece of PVC irrigation pipe to prevent damaging it with the vise, and to have a cylinder to press the old bushings out into. This worked perfectly and quickly.
    I oiled the sleeve, and pressed in a whole 1.125" bushing into the top of the housing. I then cut the lower bushing to fit, leaving a slight gap between bushings, of about 1/4", whereas the original pairing had a 5/8" gap between them. I wanted to eliminate that gap, yet retain a bit of expansion room between the bushings. So I left about a 1/4" gap between them.
    I pressed the new bushings in similarly to how I removed them, with my bench vise and socket.
    I tried fitting the newly bushed bearing back onto the spindle, and it went on very snugly, but wouldn't really rotate freely. They had distorted slightly from the pressings, so I took a 1/2" drill bit, and hand twisted it back through the new bushings to align them, and ream them.
    So I then over-oiled the spindle and bearing, and held the bearing by hand and rotated it slowly until it felt more free. At that point, I started to spin the platter, and it spun quite freely, but had a friction noise. It fit nicely and spun quite freely. So I hooked it all back up, and ran the motor to it, and turned the speed up to hundred of RPM at the platter for a half hour. After that time, the bearing went quiet, and spins freely and silently now.
    The platter rocking has gone. Its really nice, straight and rigid now. I'm calling it a success.
    Somehow, this all happened from the parts drawers at my local Lowes store - I'd never have guessed it possible.
     
  12. cactuscowboy

    cactuscowboy Super Member

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    Incredible project! This is a great example of DIY modification and workshop ingenuity. :thmbsp::thmbsp:
     
  13. Big Bill

    Big Bill Summertime Rolls.....

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    One fine idler!

    Wow french! Thats some fine work you've done there and I'm especially impressed with your replacement drive-line engineering! One question, have you "re-crosshatched" the surface of the platters shaft (in order to hold a thin layer of oil on the shafts surface) and/or honed the bearing well walls yet?




    Bill. :tresbon:
     
  14. mfrench

    mfrench AK Subscriber Subscriber

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    I'm already elated with the results of the bushing re-sleeving. Combined with the new thrust plate, the bearing is working really well.

    And i didn't cut any fingers off, or get shocked (well, ok, not too many times), or nothing! ::toothless grin::
    Many thanks. I really appreciate it. Its been a huge labor of love. It just keeps getting better and better too. She's a sweet little old lady, with allot of spunk.



    Thanks, Bill. I deeply admire your work on these old spinners, so your words mean allot.
    The drive-line engineering is a constant evolution. I didn't mention it, but I also made another idler wheel arm that is as short as I can possibly make it, and still have it hook-up. I've found that of a few widths of hole spans (pivot and arm mount holes on the idler arm), that I have span of useable width that ranges from .725" as short, to .80" The .80' arm applies to much force to the motor, making it noisy. At .70", I lose contact. At .725" I make idler contact before the switch turns on; and it takes the minimum amount of spring force to engage the wheel. At .750", I start getting motor/idler wheel noise from too much interface. The tolerances are surprising to me - tight; by pure beginners luck.
    I'm rambling,...

    I've learned massively from the effort. It makes me really want to get some proper machines and get down to it.

    Honing -
    To my understanding, you don't want to do anything to sintered bronze, or you block the pores, which is the bushings ability to become impregnated with oil.
    I'm wide open to suggestions, so please,...

    Cross-hatched -
    The spindle was never done that way when new.
    I'd love to have an oil-pumper archimedes screw cut into it, but, fear doing so, as the spindle is permanently pressed into the platter.
    Are you referring to a method of cross-hatching that I could do as a DIY'r? or a pro machining?
    Again, I'm all ears; please and thanks!

    Again, Bill, I do appreciate your words, and opinions, as a fellow builder.
     
    Last edited: Aug 9, 2011
  15. Big Bill

    Big Bill Summertime Rolls.....

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    My thinking here is that after you did this….

    …..that a little “honing” using a flap sander made from a small wooden dowel rod (available at Home Depot) with a slit on the end and some sand paper (320 grit) might be a good idea after the “reaming” you performed. Be sure not to plunge and raise the flap sander while rotating. Instead slip it down into the sleeve prior to rotating the flap sander with your drill. I seriously doubt some slight de-burring using this method would “clog the pores” of the bronze in this case.



    You can do this yourself as well. Take a 2" X 2" piece of 400 grit sand paper (oiled) and wrap it around the shaft. While slowly turning the shaft stroke the paper up and down the shaft until you can see about a 15º line (crosshatch) form in the oil film. Then wipe the shaft clean and repeat several times. Follow up with a piece of 1500 grit paper (oiled) and repeat several times as well.

    IMHO, the combination of these two improvements will help to seriously reduce any remaining friction/noise from your platter bearing assembly. :yes:


    Bill.:thmbsp:
     
  16. mfrench

    mfrench AK Subscriber Subscriber

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    Ahh,... I see. I was thinking you were suggesting a deep spiral cut into the spindle when you were suggesting cross-hatching. I'll do this tomorrow when I clean the bearing out.

    As far as honing - again, I was thinking with the 90lb hammer mentality, when a soft-faced persuader was the call.
    After I reamed with the drill bit, I did coil up some sandpaper into a "tube", and twisted it within the bearing. I did 320, 400, 600grits, which I had here at hand. The bushing sleeves are probably closer to having been cross-hatched at this point.
    I let her run-in overnight, and in the morning quiet - so was it, quiet.

    Thanks, Bill!
     
  17. Big Bill

    Big Bill Summertime Rolls.....

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    This is what concerned me and we need to remedy this by using the flap sander (320-400 grit) without any "up or down" motion of the paper while sanding. The sleeve needs to have slight horizontal groves in order to work with the 15º groves (crosshatch) on the spindle shaft.


    Bill.:thmbsp:
     
  18. mfrench

    mfrench AK Subscriber Subscriber

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    I was mostly jesting about the sleeve cross-hatching. I was quite careful with that step.
    So that you know, your words do have meaning with me; I took the bearing out again this morning, and cleaned it all out. I redid the sleeve hone, and added the spindle cross-hatch. I reassembled it all, and am running it at 90rpm now, for an hour or so. Old fashioned new car run-in theories have me running the bearing in at varying speeds, for some reason; an old habit.

    On opening the bearing up this morning, the top bushing and spindle were loaded with a film of oil - so it seems like things are going well.

    adding:
    Now, just for yucchhhss,... i finally did a speed test on what the paltter will spin up to with this DC motor, and controller.
    With one of those hand-held tachometers that read a laser reflection from a piece of reflector tape, I came in around 185rpm at full speed.
    How would you account for skating at those speeds? :)
     
    Last edited: Aug 10, 2011
  19. Big Bill

    Big Bill Summertime Rolls.....

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    At that speed even Lawrence Welk would sound like death metal! :D

    I've been wondering why you changed over from the Jelco to the "Rats Paw" (not that there's anything wrong with the Rats Paw). Was there something lacking with the Jelco??

    Bill.
     
  20. mfrench

    mfrench AK Subscriber Subscriber

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    Friendly Village of Fallbrook
    Well, I had started a second soapstone plinth project, just after I finished this Presto. That second plinth was for a Bogen-Presto B51 that I intended to convert to a heavy platter deck with a Lenco platter and bearing. I quickly got going on it, and then, got to enjoying and tweaking this Presto, and the second one got pushed aside, under a console player - (a great toe breaker under there!).
    As time wore on, I decided to experiment with a stacked platter setup, as some folk were really excited about the isolation that a second platter offered. I had a second platter, and wanted to try it out. To do so meant that the Jelco was no longer close to being high enough. So I dismounted it from the plinth top (two screws), and brought in the 'Paw from the side, because I was able to elevate it higher, and more easily.
    Well, before I knew it, I really was drawn to the 'Paw, and the way that it looked. It gave the deck a whole older appearance than the Jelco did, like a 40's or earlier look. but, more than that, the 'Paw is an amazing arm. My wife loves it. She'll ask me to hook that deck up when she wants to spin records, if the Jelco is hooked up.
    The 'Paw is an arm for a tall platter table, not a shorty, like a Lenco. The Presto is a tall deck, and then I added a second platter and barrier layers. This made this Presto a natural for the 'Paw. And with an off the scale high WAF thing going on,....

    sidetracked,....

    So, I kept looking at the stalled B51 project, and the only thing that was keeping it from being finished was the fact that I didn't have an arm for it, and, with the economy being tight, I couldn't rationalize spending on a 12" arm, when I already had the Jelco taking up shelf space. So I built an articulating brass and soapstone mounting base-arm for the 'Paw to mount it to the Presto. This freed up the Jelco to go onto a much more modern looking deck, the Bogen-Presto BP51HP_mod deck.

    The new 180lb base for the Jelco:
    [​IMG]
    [​IMG]

    Its shared (strained) table with the Presto T18DC:
    [​IMG]
    Some rough calcs had this pair ranging somewhere around 350lbs; table strain.

    At any rate,... there it is.
     
    Last edited: Nov 8, 2017

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