DIY Tonearm

[jls001]

Thanks, Sumanta for the kind words. I would love it if the machinists I go to could translate my prototype designs to function as intended without re-works. Not many of them are used to doing precision finishes though their machines are quite capable of sub-millimetric accuracies. To their credit, most of them are also quite capable of doing high-accuracy work, but it takes them more time as they need to constantly make measurements. So workflow is slower and time consuming, while their remuneration is often commensurate with the size of the finished product In other words, it can be a pain finding a good machinist, especially one who will tolerate me constantly looking over their shoulders. Unfortunately, that's the only way of getting what one wants.

 

[jls001]

Any idea where to source silicone oil? What kind of shops sell it?

I want to try it for slowing down the motion of the moving parts. So it should be thick but not too thick (if you know what I mean) to not impede the moving parts too much, but thick enough not to start leaking from the cam shaft hole. The cam shaft hole wasn't designed with the possibility of using oil damping in mind, so there is no gasket nor is the tolerance very tight. I was thinking something like 30000 cSt oil would do. Any pointers/ideas/warnings?

 

[keith_correa]

The hair products [oils!] available that claim tangle free hair on use contain silicone. Worth a try. "Livon" is a brand that I know of. There might be others

Edit: I read what you read carefully and it looks like you need a high viscosity oil - which Livon is not. Search for Silicone grease. Maybe that will work. Maybe mixing Livon and the Silicone grease will work. Maybe I'm crazy!!!!

 

[Hiten]

As silicon oil is very hard to find,
Try to experiment if you don't mind.

You can use bicycle grease my friend,
with drops of thick oil it will surely blend.

Fill the joints with very hard grease,
Leaking of damping oil will decrease.

Cover the lever joints with some sleeve,
The lift will look good is what I perceive.

Any leakages the sleeve will stop & hide,
let your amazing intuition be your guide.

Hope the arm will land in slow motion,
as y'have worked with so much devotion.

Regards

 

[omishra]

One guy suggested me "Johnsons Baby Oil" for skin which is thin and I don't know the content but same time I don't have guts to try it out.

I felt its like liquid paraffin.

 

[jls001]

Keith/Om: won't Livon hair oil/Johnson's Baby Oil flow when applied to the moving surfaces? Both are fairly thin consistency. Flow would be desirable if one is looking to reduce friction. In this case, we're trying to increase the friction. Just to clarify further - I am not looking to bath the moving part in damping oil, but just apply it to the moving surfaces like one would apply grease. My understanding is silicone oil of the correct viscosity will stick to the surfaces and not start flowing off. Or will it?

Hiten: I have tried lithium grease with the brass nut. I haven't tried it with the new teflon nut. I will try it. For now I am taking a forced sabbatical to let my thumbs heal - too much physical work gripping tiny tools, manually drilling holes in wood and brass, tapping threads, bending and shaping hard metal sheets, lots of sanding, etc over an extended period of this unending project, has given me repetitive stress injury

 

[keith_correa]

Keith/Om: won't Livon hair oil/Johnson's Baby Oil flow when applied to the moving surfaces? Both are fairly thin consistency. Flow would be desirable if one is looking to reduce friction. In this case, we're trying to increase the friction. Just to clarify further - I am not looking to bath the moving part in damping oil, but just apply it to the moving surfaces like one would apply grease.

Yeah, I realized that when I read your post carefully after I posted. And after that I edited my post.

My understanding is silicone oil of the correct viscosity will stick to the surfaces and not start flowing off. Or will it?

I don't think any oil will stick to the surface AND not run. You should be looking at Silicone grease which should do exactly what you need and which I recommended in my edited post.

 

[quad]

Silicone oil is very sticky stuff. Sachin and I used some for Tonearm damping (I got
a small tube from ebay and shared with Sachin).

You should be able to find silicone oil at so called mill shops.
If you can find the proper cst is another matter though.
Also, I read somewhere some sports shops may have them, as
it is used on treadmills.

Google baba found some -

Buy Maru Lube Silicone Oil for Puzzle Cube Online at Low Prices in India - Amazon.in

TORNADO SILICON OIL 30,000CST (50ml) - Nitro Fuel & Oil

silicon oil - India's open forum for RC flying, aeromodelling, cars and hobby stores
Tornado Silicon Oil (50ml)

 

[jls001]

You should be looking at Silicone grease which should do exactly what you need and which I recommended in my edited post.

Thanks.

Any idea if silicone grease has higher viscosity than lithium grease? Do grease also come in various viscosity grades?

 

[jls001]

Google baba found some -

Thanks for the pointers, quad!

 

[jls001]

Finally re-assembled the tonearm with the arm lift.

Arm lift is kept straight and not curved like in many arm lifts. This is to keep things simple. As it is, I struggled to get this rod perfectly level so that it has equal lift at the beginning and the end of rod (outermost and innermost groove).

There is some extra length of the arm lift (black horizontal rod) even at the inner most groove. I will let it be and not shorten it, as I don't want to dismantle it again. It's not adversely affecting operation.

The drop is not yet upto the level of what I had envisaged, but it works fairly well. It's way more convenient than dropping the arm nervously by holding it at the headshell lifter.

So for the present, this project is complete. It's been a steep learning experience in wood working, metal working, spray painting and tonearm geometry. Most of all it's been great fun making your own arm, complete with a fancy lift I had some expectations of the sound, but I was blown away by how good it sounds. It's now the primary arm on my Lenco L75 TT.

A highly recommended project.

Some numbers for those inclined:

Pivot to spindle distance: 294 mm
Overhang : 13.22 mm
Effective length: 307.22 mm
Headshell offset angle: 18.1 degrees

I have plotted the tracking error too and it is comparable to a Baerwald or a Loefgren across most of the groove, while it betters the two in some parts of the groove.

 

[Sumanta]

Bravo, Bravo!

 

[Hiten]

Nice work Joshua.
What are the Plinth Plans ? You probably know This from Francois looks like top notch effort. (Right click and translate to english, if using google chrome) Since we don't have Panzerholz plywoods one can use High density plywood and some damping material.
Regards.

 

[jls001]

Regarding plinth, I have studied lots of designs and have sort of finalised on throwing away most of the Lenco top plate, retaining only the pan area. This eliminates the weak top plate and gives freedom to use any tonearm. I am planning a large generic arm board that will be able to accommodate 9 to 12 inch arms. Only the arm board will need replacement for swapping arms. For size, I will definitely not go overboard this time. It will be just sufficient to accommodate a 12 inch arm, while hopefully retaining an aesthetically pleasing width x depth x height ratio. I will limit plinth height to within 4 inch.

For material I've toyed with the idea of using stone but have come round to accepting dense plywood as perhaps the best compromise. Also, I will stick to one-arm setup. A two-arm setup is too much trouble for me, and I have realised that it's difficult to fully optimise both setups. So I will try to max out one arm setup in terms of giving it the best (within my limited means) arm, cartridge, tonearm cable and internal wiring, and not the least, phono preamp. And at a much later date in the future after I've sufficiently played around with all three, I will have to choose one of the three TTs I have - can't have all of them.

 

[Tanoj]

Congrats Joshua

superbly crafted Tone arm that too with lift mechanism :clapping:

i am looking for a Straight tone arm to build a liner tracking TT,

I can gain knowledge on diy from you, it will be great if you pm me your number

Best Regards

Tanoj

 

[jls001]

superbly crafted Tone arm that too with lift mechanism :clapping:

i am looking for a Straight tone arm to build a liner tracking TT,

I can gain knowledge on diy from you,

Thanks, Tanoj.

I know next to nothing about linear trackers. I too would love to build one, especially something simple not involving noisy air pumps. BTW, very interesting developments in pivoted tangential tracking tonearms (not the same as conventional linear trackers) are unfolding in diyaudio. Do Google "Angling for 90 Degree Tangential tonearms". Some seriously knowledgeable arm designers are actively participating, and I get a feeling the day is not far when diy-able designs will be published.

In the meantime, I will be happy to help if you want to try your hands on a conventional unipivot.

Just to understand more about conventional tonearm, I'm keen on making a gimballed arm. I have a couple of faulty hard disks from which I plan to cannibalise platter bearing and read head bearing. They're supposed to be nearly frictionless and can be used as horizontal and vertical bearings, respectively.

 

[Tanoj]

Just to understand more about conventional tonearm, I'm keen on making a gimballed arm. I have a couple of faulty hard disks from which I plan to cannibalise platter bearing and read head bearing. They're supposed to be nearly frictionless and can be used as horizontal and vertical bearings, respectively.

Actually i have a sansui linear traking tt, which has plastic body and plastic tonearm, that is why i was planing to replace the body and tonearm with wood

basically i need to build a straight tonearm like this however with wood and mount it on the same moving trail on which currently the plastic tonearm is moving

few more changes i wish to do is use a tone arm wire like this , connect one end to cartridge and other end goes straight to the phono stage board ( sachin's cnc phono stage ) , that way there is no signal loss, no interconnect cable etc

the third thing i want to do is somehow increase the platter weight or damp it more

Thank you

Regards

Tanoj

 

[jls001]

The Sansui linear tracker is most likely electronically servo controlled.

I'm not sure if replacing the arm wand with another material would be beneficial, as it is likely that the servo would be tuned for the mass of the current arm wand, and you'll probably have to match the mass. Typically linear tracking arms have very high mass in the horizontal, but vertical mass is usually low. May be you can come up with a structure that will be more rigid, more damped, and no weight penalty in either axis

Rewiring is always a good idea.

 

[kuruvilajacob]

The Sansui linear tracker is most likely electronically servo controlled.

I'm not sure if replacing the arm wand with another material would be beneficial, as it is likely that the servo would be tuned for the mass of the current arm wand, and you'll probably have to match the mass. Typically linear tracking arms have very high mass in the horizontal, but vertical mass is usually low. May be you can come up with a structure that will be more rigid, more damped, and no weight penalty in either axis

Rewiring is always a good idea.

I think the Linear track arms of Sansui Turntables work in such a way that they tend to drag the arm to the next groove and this I understand damages the inner grooves. One reason why those Linear tracks were not too popular those days. The very high end Clear audio Turntables use the linear principle but the movement is using a different system.

 

[Hiten]

I had Technics SL-5 Linear turntable. It was okayishly good.

????? ?? ???? ?????? ?? ????? with linear Servo Tonearm you have varying tracking error through out the record but is very less than pivoted tonearm which has zero tracking error at two null points and comparatively higher when moving towards/opposite these two null points.
I guess once again one has to choose one's poison in audiophile hobby.

Regards

Clearaudio ??????? (Tonearm) ?? ???? 4.5 ??? ??? ?? ???? ????? Turntable, Preamp, cartridge ?? Records ?? ??? ???????? ?? ???? ???