DIY Tonearm
- Thread starter audioflyer
- Start date
audioflyer
No going back once you heard a ceramic cartridge
It is possible to print metals too Rolls Royce have be using it for years to make turbine blades.
Have a look here.
http://gpiprototype.com/services/metal-3d-printing.html
Have a look here.
http://gpiprototype.com/services/metal-3d-printing.html
orangeart
KJF Audio Ltd.
Those Rolls royce turbine blades are sheer madness, they operate in temperatures way beyond their melting point by employing complex methods of thermo and hydro dynamics to give a cooler skin of air just microns thick between them and the heat of the rest of the engine. Truly amazing use of mathematical models and a company us brits should be very proud of.
Paul R
pfm Member
If this project progresses at a reasonable price, then I will buy one. It would be good to define 'reasonable price' but I think we'd know it when we see it. Perhaps somewhere between a Rega RB202 and RB303?
If bits of aluminium are being milled, it might be worth considering a mounting and/or alignment jig. Something that replaces the arm in the base and has a hole for the turntable spindle would be a boon. Similarly for arm base to stylus. Especially for a 12" or 10" version.
Paul
If bits of aluminium are being milled, it might be worth considering a mounting and/or alignment jig. Something that replaces the arm in the base and has a hole for the turntable spindle would be a boon. Similarly for arm base to stylus. Especially for a 12" or 10" version.
Paul
John Channing
fruit box forever
This would be to ensure correct installation rather than construction?
John Channing
fruit box forever
Can anyone with an Aro tell me what the headshell, bearing housing cup and counterweight stub are made from? Are they all aluminium alloys or is the counterweight stub made of something else?
TPA
Trade: Tiger Paw
Headshell and main housing are aluminium, not sure of the grade. Bearing cup is made from tool steel (I think) - and this feeds in to an extremely close tolerance steel sleeve with a ball bearing at the bottom. Counterweight stub is steel, and decoupled with a hard rubber from the main housing. I've made several different unipivot arms based loosely around the concept of an Aro replacement. Essentially changing the masses and materials in different areas alters character. One of them was superb but I'm overcome with inertia when it comes to hifi bits at the moment and not sure I want to get involved in another project.
One of the areas to look at is the relationship between pivot point, stylus and counterweight (in vertical plane)
I got a quote from FirstCut today for a headshell. Pretty similar cost to eMachineShop for small quantities, approx 90 euros per piece (plus VAT I guess) for 1-5. No real discount for larger quantities. Still waiting on a reply from some smaller local shops.
I checked Shapeways and they can 3d print it in stainless steel* for $25. No idea what the finish will be like, but might be worth a punt for the price.
* they can do platinum too if that floats your boat
I checked Shapeways and they can 3d print it in stainless steel* for $25. No idea what the finish will be like, but might be worth a punt for the price.
* they can do platinum too if that floats your boat
YNWOAN
100% Analogue
The headshell and main bearing bell are anodised aluminium - as is the counterweight stub - definitely.
Ah, I see TPA says the stub is steel - I don't think it is though; It's definitely anodised. The counterweight is chromed brass.
The main bearing shaft and inner element, ball and end cap all look to be stainless steel.
Pete MB&D
Pete Maddex, the one and only!
Don't fancy cleaning up stainless! It's tough stuff.
Can't we simplify the head shell? It looks like a part that could be made with less machining.
The flat for the cartridge seems to extend back towards the arm quite a way, a smaller platform and a slot to connect to the hole into the arm tube might be stronger but a little heavier.
A hight adjustable counterweight might be a good idea.
Pete
Can't we simplify the head shell? It looks like a part that could be made with less machining.
The flat for the cartridge seems to extend back towards the arm quite a way, a smaller platform and a slot to connect to the hole into the arm tube might be stronger but a little heavier.
A hight adjustable counterweight might be a good idea.
Pete
TPA
Trade: Tiger Paw
Might be worth doing what I did with the Aro sKale counterweight - offset the centre hole and that will give you finely adjustable azimuth.
There's a lot to be said for making the headshell from a similar material to a cartridge which will transfer energy in a predictable way.
TPA
Trade: Tiger Paw
Sorry, my bad, the c/w stub is indeed aluminium.
Paul R
pfm Member
Yes. I think the alignment is critical, and often ends up wrong. Except with Linn carts and Linn/Naim arms on LP12s....
So it might be worth considering as part of the exercise.
But it's possible that a jig might be necessary for construction, should an arm tube need cutting for example. Perhaps there's a uni-jig to be discovered.
Paul
John Channing
fruit box forever
This is the part of the Aro design I find intriguing. They have basically put together what looks like a bearing - a shaft sitting on a ball bearing in a close tolerance oil filled cylinder which as far as I can tell is only used as a damping mechanism for dumping energy from the arm tube. It adds complexity and also potentially a lack of stiffness to the design, is it really needed?
Some of the theory on this from Graham and Pierre Lurne.
YNWOAN
100% Analogue
Does the Aro skale have the same course thread as the original? If not I assume it also isn't tensioned against the stub in the same way. Unless a secondary element is used an eccentric weight would have to be locked to the stub and that would impact upon the resonant signature.
Paul R
pfm Member
It's unclear to me what the damping fluid is damping. Or why the parts of the bearing support would move independently. Is it obvious if you handle an ARO?
Paul
TPA
Trade: Tiger Paw
I tend to agree with you. I've heard various comments about why that part of the design was implemented, but as you say, whilst it provides a direct coupling to ground (single point to the ball bearing) it potentially allows for lateral movement. I have a 'solid' version with the same cup if anyone wants to try it out.
YNWOAN
100% Analogue
Yes, you summarise the design well I think. As you say, it is an unusual solution but to know the impact it has one would have to duplicate the same part but without the damped bearing element.