a couple of turntable restorations

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Vinyl-ant
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Re: a couple of turntable restorations

Unread post by Vinyl-ant »

Hmmm. Just tallied up what it's cost me to build this thing, bear in mind that this wasn't all spent at the same time, and includes the cart, but it's cost me just over 900 quid :shock:

Quite frankly that's abit daft, I'm very aware of the costs involved when I do something for someone else, but it never occurs to me what I've spent when I build something for myself..... Its something of a shock to be honest, I shall have to start looking at costs more closely when I do build stuff for myself.

I wonder if it's worth it. (I think it is, but I'm biased)
Also wonder what alternative I could have bought for that money, I haven't a clue what's on the market these days.

I haven't included the pop bottle plenum tank I made yesterday and added into the air line to smooth the airflow into the arm bearing in the costing though :lol:
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Re: a couple of turntable restorations

Unread post by Latteman »

+£1.09 they cost unless u went with Peter Kaye rola cola 👍🏼
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Re: a couple of turntable restorations

Unread post by Vinyl-ant »

I got abit bored today and was tidying through a load of my many boxes bits and pieces. I was chucking bits and pieces that have been in one of the boxes for god knows how long. I found a small 5 pin locking connector, which set wheels turning, so I decided to replace the awful old connector on the JBE that connects the control box to the motor.

This is the original connector. It was crap in 1978 and is even more crap now

ImageJBE series 3 with airprodigy arm by anthony cresswell, on Flickr

I've always had issues with it ever since I bought the deck, so it's now gone. Had to make a bracket for the new socket, and replacing the plug on the end of the flying lead was abit of a pig as the connector is abit small. Got there in the end though.

Unfortunately for everyone in the house demanding my attention, things escalated from there as I decided I wanted to try the airprodigy arm on the deck as it has been sat unused for about 12 months, (partly because of the dodgy old plug) and seeing it spinning for the first time in a long time set me off.

The arm board needed surgery to fit the new arm as the last arm it had on it was the at1100 i had. So I stuck it in the lathe and machined off the original perspex face, superglued a new bit of perspex on and then machined it round.

ImageJBE series 3 with airprodigy arm by anthony cresswell, on Flickr

Then measured it up, drilled it for the mounting bolt and tapped a thread into the perspex. Then dragged the Lenco out and pulled the arm off it and fitted it onto the JBE.

ImageJBE series 3 with airprodigy arm by anthony cresswell, on Flickr

Sounds really good.

Took me a few hours to replace the connector, sort the arm board and mount and set up the arm, and tidy up the absolute devastation I'd caused, but it was a nice job to do. Killed a few hours.
Never did finish going through all the parts boxes......
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Firebug1 (Sat Mar 06, 2021 9:34 pm) • Daniel Quinn (Sun Mar 07, 2021 4:41 pm) • antonio66 (Mon Mar 08, 2021 2:48 am)
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Re: a couple of turntable restorations

Unread post by Vinyl-ant »

Been busy.

ImageCx unipivot mk 4? by anthony cresswell, on Flickr

All the parts for the wand itself are done, as is the bearing and arm pillar

ImageCx unipivot mk 4? by anthony cresswell, on Flickr

The pillar was machined from a piece of 25mm black bar, big bit is 18mm, thin bit is 12mm. The bearing cup is machined in the thin end.
The big bit has a 7mm hole up through it so that i can put silicone in it to damp the part.
I can take a reliable pass of about 0.2mm in steel with carbide inserts with my md65 lathe, any more than that and it gets abit laboured so it took a while to machine it down to what i wanted. I like to try to get the longest spirals i can when cutting, got some good ones doing this :D

ImageSpirals of steel by anthony cresswell, on Flickr

The outrigger which will hold the arm rest will sit on the shoulder and have a small setscrew through it to secure it to the post.

These are the bits so far

ImageCx unipivot mk 4? by anthony cresswell, on Flickr

The wand is carbon fibre, the bearing housing, counterweight stub and cartridge mount are made of Delrin. I decided to try Delrin as I like the fact that it is not very resonant. Im going to damp the arm wand internally with rubber baffles when i come to assemble it.

wiring will run inside the tube and exit out of the side rather than through the front, it will then come out of the top in a loop and plug into a connection box.

To make the cart attachment i turned the delrin down to the size I wanted, then used the little proxxon dividing head to hold it and mill it flat on the top and bottom, then mill out the slot.

to drill out all the required holes in the bearing housing i did the same, as the compound table allowed me to find the centre of the cylinder and drill the pilot holes at the required angles.
I then had to bodge the compound table onto the drill press table so i could use the drill press to make the correct sized holes. the biggest bit i can get in the milling machine is a 4mm.

next bits are a counterweight, an outrigger and a collar for the arm. delrin does not like being sanded though so finishing will be thought provoking

but not today

onwards!
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Re: a couple of turntable restorations

Unread post by antonio66 »

:epopc:

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Re: a couple of turntable restorations

Unread post by Vinyl-ant »

Bit more progress on this, I've got some more parts made

ImageCx unipivot by anthony cresswell, on Flickr

I've done the counterweight (turned from some black bar), the height adjustable mounting collar and the nut, part of the arm rest, and the cartridge mount. Theres an old vms3 on it to check it worked as intended.

The delrin ring with the smaller hole is part of the arm rest. This goes over the arm pillar and slides down to the shoulder where it will be epoxied in place. There are going to be 2 5mm x 50mm aluminium rods coming out of it, one for the arm rest and the other at an angle to carry the bias weight guide. The bias guide rod will be trimmed when I've checked how long it needs to be.
The collar was the first time I'd done any threading on this lathe, a bit of a pig to set up because of the 4 change gears for the power feed, and the fact that the dog clutch was not playing ball and had to be taken apart to get it to work. The internal thread on the nut was simple enough once the clutch was fixed
Need some more m3 setscrews for the height adjust, but the normal machine screws will do for now.

ImageCx unipivot by anthony cresswell, on Flickr

the drill bit stuck out of the from of the arm rest collar shows where the arm rest bar will go.

ImageCx unipivot by anthony cresswell, on Flickr

The cart mount was simple enough to do, 4mm thick so that there is plenty of thread for the mounting bolt, and the cart sits in line with the bottom of the arm tube which is where the pivot is at the moment. Although it looks a little messy because I forgot to reset one of the dials on the mill to 0 so the cutouts for the mounting nuts aren't exactly right. I can't be bothered to redo the part at the moment, it's a prototype anyway. I didn't have the right length m3 bolt to fix it on, hence the pair of nuts to space it up so it doesn't hit the top of the cart. Another thing to add to the list of bits to buy for it.

ImageCx unipivot by anthony cresswell, on Flickr

And it dry assembled.
to the left of the dummy drill bit you can see the hole where the bias guide arm will come out.
Next jobs are to mill some flats into the mounting collar nut, make a pair of lateral balance weights that are heavier than the thumbscrews Iv'e used to test it, make the rest of the arm rest when the rods turn up, and drill and tap the counterweight for a locking screw.

onwards!
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Firebug1 (Wed Mar 17, 2021 6:25 pm) • slinger (Thu Mar 18, 2021 5:53 pm)
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Re: a couple of turntable restorations

Unread post by Vinyl-ant »

I had a think about the lateral balance weights, and rather than making a new pair I decided to install a ring weight into the bottom of the bearing housing instead.

ImageCx mk5 bearing housing by anthony cresswell, on Flickr

Can't see it too well on the picture but the ring was made from some 40mm steel bar, so I had to turn it to the correct diameter then drill and bore the internal diameter. Then part it off. This lathe doesn't do parting off of steel very well, aluminium, brass, and the delrin are no problem, but it has trouble with steel. It just isn't rigid enough. I got about a third of the way through and bottled it, took it outside and sawed it off instead. Then just faced it off on the milling machine. Much less taxing.

The ring is 3.5mm thick and weighs 12g which is just over what I wanted (10g) and is enough to lower the centre of gravity. It's now abit lower than it was and has stopped the tendency to want to fall over when the pivot it in line with the centre of the counterweight stub.

I machined a recess into the underside of the housing for it to fit in, and while I was at it gave the housing a very light skim pass to refinish it. Delrin really needs to be machine finished, it doesn't respond well to sanding as I discovered. So it looks better now. Having bought a 4 jaw chuck, I now think it's definitely worth having in spite of the faff to set it up with a dti every time, I wouldn't have been able to put the part back in the 3 jaw and it be concentric.
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Re: a couple of turntable restorations

Unread post by Vinyl-ant »

Nearly there

ImageCx mk 5 unipivot by anthony cresswell, on Flickr

The parts for the arm rest and the bias guide are now done, and the correct setscrews and button head machine screws have arrived so have been installed
Also installed are the arm finger lift, and a 3mm grommet I found in the spares box for where the wiring will come out of the arm tube. Still need to drill a hole in the top of the bearing housing for the wiring to exit.

ImageCx mk 5 unipivot by anthony cresswell, on Flickr

The two outriggers for the arm rest and bias guide are aluminium, the bias guide itsself, the upright for the arm rest and the finger lift are 2mm stainless. The outriggers have height adjustment for the rest and guide via button head machine screws in the ends of the rods

ImageCx mk 5 unipivot by anthony cresswell, on Flickr

The rest is just made from a bit of delrin rod, it needs some fettling yet, but I cant be arsed today.

Just need some wiring, and the silicone tubing to arrive that will be inside the arm tube to damp it.

I worked out the effective mass of it as is, and it came out at 7.3g. With the silicone tubing inside the arm tube it comes out at about 10g based on an estimate of the difference in weight the tubing will make. This was based on a cart, mounting plate, and fixings figure of 12g. I took a sample of quoted weights of 20 different carts to get an average, which was 8.3 and change.
10g should be fine. I'll redo it once I know the actual weight figure

I could start gluing it all up, but I want to do some drawings of all the parts before I do. Like usual, I started off with a drawing of the idea, but then the rest fell out of my head so I haven't planned all of the bits.
If I want to reproduce it I'd better have all the details to hand........
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karatestu (Sat Mar 20, 2021 5:48 pm) • savvypaul (Sat Mar 20, 2021 6:10 pm) • Firebug1 (Sat Mar 20, 2021 9:03 pm) • antonio66 (Sun Mar 21, 2021 12:55 am)
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Re: a couple of turntable restorations

Unread post by Vinyl-ant »

Closer

ImageCx mk5 unipivot bte designs type 3b lenco by anthony cresswell, on Flickr

Got the dry built arm on a deck, not much use on its own..... It required a new arm board to be made. I just drilled the middle out of the original one, skimmed the face of it down in the lathe to reduce the height to take the perspex into account, then put a perspex face on it and turned it to match the diameter of the original. Then used my dr feickert setup jig to scribe it at the right s/p distance and drilled it for the arm. Simple

ImageCx mk5 unipivot bte designs type 3b lenco by anthony cresswell, on Flickr

Looks quite nice on this type 3b Lenco

I chose this one to put it on rather than my other type 3(a) because A: the other one is on the top of the wardrobe and its really rather heavy so I couldn't be arsed to try and get it down, and B: this one is almost identical to the one that mi dad has so it can be compared with the SME 3009 on his without faffing about. Need a pair of the same carts though and I don't know what it is on his.
But thats getting ahead of myself, I've still got to install the damping for the arm tube, wire it, and make a bias weight. I suppose I could buy a bias weight, but why bother, I've made everything else..
Waiting for bits is a pain

Onwards!
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Latteman (Mon Mar 22, 2021 6:28 pm)
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Re: a couple of turntable restorations

Unread post by Latteman »

Both look bloody stunning
Analogue Source -
Diy Turntable ,- Thorens Td321 donor
Diy tonearm- Well Tempered clone,
Benz Micro Silver
Hitachi HT-660, Ortofon vivo blue
Phono 1 (160va) & Ortofon MCA10
Digital Sources- MF M1 Clic, Diy IDE cdp, iPhone 6s.
Amplification 2x Nva A20; A30 mk2; AP10H; Khozmo passive pre
Speakers- Diy ‘Bipolar 5.25” in bamboo sphere ; Ls6/3
Dc blocker to Nva mini BMU

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