Knob turning

[Brudha]

Anyone successfully try turning the original aluminum knobs on a metal lathe to take out deep scratches on the face?

Is it possible to do without ruining the knob?

Is there any clearcoat spray applied originally?

Are all the G-series' volume and tuning knobs interchangeable?

 

[LBPete]

The knobs and other aluminum surfaces are anodized. If you turn them, you will loose this surface treatment. I don't think they were clear coated. There is a current thread for a G-9700 knob that discusses turning new ones. Also, this thread has a discussion on aluminimun surface treatments. http://audiokarma.org/forums/showthread.php?t=52582

- Pete

 

[gamalot]

I have no experience with turning knobs but I can tell you for sure that all G series knobs are not the same. Slight variations exist and I am not sure if it is model specific, date or where the unit was manufactured.
The variations I know of have to do with height of the knob as well as the bevel on the face and the knurling on the knob edges. Seems that knobs that have a deep V also have a more course knurling while knobs that have a mild V have finer knurlings.

Pioneer727 sent me a knob from a G 3000 and it is about 1/4" shorter then those on the G 7,8 & 9K units, otherwise it is the same look.

Post a picture of your knobs and I will let you know which style you have.

Gary

 

[Inspiribomb]

While it is probably possible to do this, I would have a few concerns:

1) As mentioned before, any anodizing would be removed.

2) My main concern, actually, is how would you hold the knob in the chuck without a) wrecking the knob (chewing into the aluminum) or b) lining it up so that it spins true. You also hafta figure out how the heck you're going to hold the knob in the chuck and still be able to get the tool bit in close enough without hitting it on the chuck.

My recommendation: find a parts unit or similar model to get knobs from, you'd probably have to anyway after destroying them in a lathe.

 

[rek50]

Bomb, a "Donor" splined shaft (L-Pad, for instance) could be "Chucked-Up" and the knob to be treated, pressed on the shaft. Indicate the face and "Tap" it true. A "Half-Thou" cut wouldn't knock it out of Whack.

 

[Inspiribomb]

Bomb, a "Donor" splined shaft (L-Pad, for instance) could be "Chucked-Up" and the knob to be treated, pressed on the shaft. Indicate the face and "Tap" it true. A "Half-Thou" cut wouldn't knock it out of Whack.

You could do that. Or, you could just try to find a replacement knob. Aren't the Sansui knobs flat across the face? My 700 series Kenwoods would be fairly difficult to do this to, as they are tapered and you would have to set a profile for the lathe.

Anyone successfully try turning the original aluminum knobs on a metal lathe to take out deep scratches on the face?

How deep are these scratches?

 

[Brudha]

Volume knob:

 

[rek50]

Red Green would probably chuck up a donor splined shaft in a hand held drill motor (Held still in a vise) and procede to "Tune Up" the face of a tapered-face knob with wet or dry sand paper. Coarse then fine to suit.

 

[Inspiribomb]

Brudha, you might want to look for a new vol. knob. Depending on how deep those scratches are, if you face off the front of that knob, you very well could lose that nice little point where the notch is by the time the scratches are gone.

 

[gamalot]

Brudha, That is the coarse version of the Standard G 8 & G 9K knobs.
Probably the easier to locate but still pretty hard to find. They are the knobs on three of my units. Only ever saw one with the finer version. By the way, both versions are interchangable. Splined on all the smaller knobs and set screws for the two large ones.
To the best of my LIMITED knowledge, think you need to find a G8 or G9K unit for that knob. The smaller ones are interchangable with lower models but I THINK, the large knobs might not be.

You need someone like Hillman to chime in here as he owns a number of smaller Gs as well as the big ones and could give a more accurate accounting as to what fits what.

Gary

 

[Morden2004]

Commonality in units

In general, most of the G-xxxx line didn't interchange knobs except when two models shared essential parts; like a G-8000 and a G-9000. Knowing which units are 'shared' can help locate parts.

I know, for example, that the G-6000 has slightly smaller knobs that the G-8000 but I suspect that it shares parts with the G-7000. As a point of interest, certain models are combined into one service manual - for example the G-6000 & G-7000 share a SM and the G-8000 & G-9000 share a SM. It is this pairing of units that I believe makes parts interchangable between units.

In the G-6000/7000 service manual, both units are identical except for the power amps. They share all the same controls and knobs and even the same driver board. Same for the G-8000/9000 with the exception of the G-9000 AM/FM section & front-end pack, the equalizer and tone SW circuits and, of course, the power amps. The G-9000 has 3 additional front panel switches but shares the same chassis.

So, my point is knowing commonality can assist in finding replacement parts.

Paul

 

[gamalot]

Paul, I can't disagree with anything you said except that Sansui threw us a curve ball on the difference between what I am calling the coarse and fine knobs.
I own 2 G 9000s that have the heavier or Coarse knobs and I own a G 9000DB and a G 8000 that have the Fine or lighter knobs.
I have no idea where the difference comes from but it is apparent in these photos.
I do wish I had your EOS to get some really fine photos!

I do hope this shows the major differences, all are the large tunning knobs and from the top view, the wider bevel also results in a much deeper V slot on the other knobs.

Gary

 

[Morden2004]

Another monkey wrench

Goes to show you that just when you think you've got it all figured out they toss a wrench in the works :sigh:

I wonder since Sansui often built these units on multiple different manufacturing lines they also sourced their accessories local to that plant (line) - for example a line in Japan vs. a line in, say, Tiwan. Possible. That would explain slightly different knobs with basically the same dimensions.

Paul

 

[gamalot]

Paul, Interesting, however this does not compute!

All of my units are made on the same line if I have the codes fi
gured out correctly. They all start with 81.

The oldest is 81801 which is a G 9000 made in Jan, 1978 and has the heavy or coarse knobs.
Next is 81802 which is a G 9000 made in Feb, 1978 and has Heavy or coarse.

Next is 81812 which is a G 8000 made in Dec, 1978 and has Fine knobs.

Last is 81901 which is a G 9000DB made in Jan 1979 and has Fine knobs.

I think somewhere between the beginning of 1978 and the end of 1978 they switched from heavy to fine knobs. It will be interesting if others with dates in between gave us the facts of which knobs they have.

Gary

 

[Brudha]

Paul, Interesting, however this does not compute!

All of my units are made on the same line if I have the codes fi
gured out correctly. They all start with 81.

The oldest is 81801 which is a G 9000 made in Jan, 1978 and has the heavy or coarse knobs.
Next is 81802 which is a G 9000 made in Feb, 1978 and has Heavy or coarse.

Next is 81812 which is a G 8000 made in Dec, 1978 and has Fine knobs.

Last is 81901 which is a G 9000DB made in Jan 1979 and has Fine knobs.

I think somewhere between the beginning of 1978 and the end of 1978 they switched from heavy to fine knobs. It will be interesting if others with dates in between gave us the facts of which knobs they have.

Gary

The knob in question is off of a G-9000DB made in June, 1978 on line 81.

 

[Morden2004]

But wait, there's more

Paul, Interesting, however this does not compute!

All of my units are made on the same line if I have the codes fi
gured out correctly. They all start with 81.

The oldest is 81801 which is a G 9000 made in Jan, 1978 and has the heavy or coarse knobs.
Next is 81802 which is a G 9000 made in Feb, 1978 and has Heavy or coarse.

Next is 81812 which is a G 8000 made in Dec, 1978 and has Fine knobs.

Last is 81901 which is a G 9000DB made in Jan 1979 and has Fine knobs.

I think somewhere between the beginning of 1978 and the end of 1978 they switched from heavy to fine knobs. It will be interesting if others with dates in between gave us the facts of which knobs they have.

Gary

No no no! It's not supposed to work that way.



Sorry, too much coffee today.

Just checked my pair of G's and I think they are both 'fine' knobs. At least to my eye and using your photos as a guide.

The G-6000 serial is 818061991 (June 1978) and my G-8000 is 857110141. But wait! What's this??? Not line 81??? But it seems to have those 'fine' knobs and it's a November 1977 unit - older even than your collection! :sigh:

See, just what I was saying in that last message - something always comes along to screw it up. :yes:

Can you tell from these shots?

G-6000 knobs

G-8000 knobs


Paul

 

[gamalot]

Paul, Both your units appear top be coarse knobs as is Brudhas.
Measure the shinny edge cut on each knob face, a little more then 2/32nds for the fine and a bit more then 4/32nds for the coarse.
It looks like the coarse was in style thru June 1978.

Gary

 

[PC Bob]

Volume knob:

It looks like this one has a taper also. I would be more inclined to try polishing it out. I don't know how deep the scratches are, obviously, but I would think maybe some really fine polishing compound on a cloth while you spin the knob in the chuck? That's a beautiful knob otherwise; it'd be shame to ruin it completely.

Just my thoughts on it.

 

[gamalot]

Gee Brudha, I have some inside info and some bad news for you.
In June of 1978, line #81 had a nuclear meltdown which contaminated all the G 9000DBs made that month! Since I am a certified HazMat guy, among other certifications, You should just send that thing to me for proper disposal.
It aint no G 33000 so it aint a big deal!

Actually I think your knob will be easier to locate then the newer and fine ones.

Gary

 

[Hillman]

The G-8000 & G-9000 have the same type knobs. Some of the smaller knobs on the G-6000 & G-7000 are the same design and will work on the G-8000 & G-9000. The G-9000DB has completely different knobs. The knurling on the sides is much finer and the beveled outer ring on the front is about half the width of a G-9000. Also the diameter of the front of the volume and tuning knobs is smaller on the DB series.

If the scratches are not to deep, you could use the Red-Green method, what do you have to loose. It is not rocket science here. Remember, If the women don't find you handsome, they should at least find you handy!