Hi guys / Frank,
I'm making a new version of my DIY arm and am hoping to get an opinion about piggy back riding magnets...
I have N52 10mmx5mm magnets drilled but am also thinking of putting a smaller 6x2mm magnet piggy back riding the bigger one to increase the flux. This I would do to both the arm and stationary magnets. Would this be ok, or do you guys see any downsides of this?
- Jukka
I'm making a new version of my DIY arm and am hoping to get an opinion about piggy back riding magnets...
I have N52 10mmx5mm magnets drilled but am also thinking of putting a smaller 6x2mm magnet piggy back riding the bigger one to increase the flux. This I would do to both the arm and stationary magnets. Would this be ok, or do you guys see any downsides of this?
- Jukka
Hi Jukka,
You won't increase the flux, but create a more stable bearing = more pronounced restoring force.
This would yield a significant change(increase) of VTF when the arm is raised, as in when it tracks a thicker pressing(200gr vs 150 or 120) and puts more stress on the cantilever when riding a warp... you get the picture.
If you want to keep flux density at a max. close to the center and not change the entire overall layout, you'd need to decrease the thickness of the larger magnets to, say 10x3mm, then add you smaller magnets(i.e. 6x2mm)
But you need to center those relative to the bigger ones(and keep them centered), - not at all easy.
Good luck with your project!
Frank
You won't increase the flux, but create a more stable bearing = more pronounced restoring force.
This would yield a significant change(increase) of VTF when the arm is raised, as in when it tracks a thicker pressing(200gr vs 150 or 120) and puts more stress on the cantilever when riding a warp... you get the picture.
If you want to keep flux density at a max. close to the center and not change the entire overall layout, you'd need to decrease the thickness of the larger magnets to, say 10x3mm, then add you smaller magnets(i.e. 6x2mm)
But you need to center those relative to the bigger ones(and keep them centered), - not at all easy.
Good luck with your project!
Frank
Hi Duke58.
I happened to have a supplier near by. But if you don't, then there are plenty of web sites to chose from... Haven't seen any with suitable holes though.
I had a couple of magnets "drilled" at an EDM shop once, but the result wasn't very good.
Now I've practiced to drill the holes my self. But to do that, you do need a drill press, really sharp drill bits, figure out a jig, have lubrication, have precision, have consistency and still you need quite a bit of practice (= plenty of magnets).
It is not easy but can be done.
I happened to have a supplier near by. But if you don't, then there are plenty of web sites to chose from... Haven't seen any with suitable holes though.
I had a couple of magnets "drilled" at an EDM shop once, but the result wasn't very good.
Now I've practiced to drill the holes my self. But to do that, you do need a drill press, really sharp drill bits, figure out a jig, have lubrication, have precision, have consistency and still you need quite a bit of practice (= plenty of magnets).
It is not easy but can be done.
@Jugi63-- are you using carbide drills? I've tired to drill magnets, haven't had much luck. Take them to an EDM shop, adds to the cost because they have a minimum/setup charge of $50.
Any recommendations on any particular magnets to buy? I don't know what size magnet to use for the Schroeder Tonearm.
Thanks,
Duke
Any recommendations on any particular magnets to buy? I don't know what size magnet to use for the Schroeder Tonearm.
Thanks,
Duke
Anodizing Aluminium
Frank(berlinta)
Do you have any experience with anodizing any of the metals used in your tonearms, specifically the Reference model? For instance, anodized & dyed metals effecting the Eddy currents? Or any other variables that could change the characteristics anodizing would cause. Thank you for any insights you may have.
Scott
Frank(berlinta)
Do you have any experience with anodizing any of the metals used in your tonearms, specifically the Reference model? For instance, anodized & dyed metals effecting the Eddy currents? Or any other variables that could change the characteristics anodizing would cause. Thank you for any insights you may have.
Scott
Hi, Strike3 and others interested in making Frank's tonearm.
1. Frank is a VERY skilled machinist / designer with proper machinery that very few people here can match !! Stick to your skill level and be realistic with the results you can obtain.
2. PLEASE , PLEASE stop with the attempted drilling / EDM of the magnets !!!! It is not done in the Reference arm or other arms that i am aware of. It is a total waste of time, energy, machine time, drills etc. Take a GOOD look at some of the arms people actually made !
Some tips :
I used large diameter, precision arrow shafts ( largest legal diameter in U.S.A is .4200". These are round within .0001 for the 31" length. These are 7075 aluminum , hard anodized. There is a brass / aluminum disk (about 3mm thick)that is drilled through to accept the string / knots. This disk is the same diameter as the top magnet and placed in the well on top of the UNDRILLED magnet. I personally made 4 "hourglass" shaped washers 6mm long that are drilled to accept 3mm thin walled teflon tubing. This tubing comes out the back and front of the 10" arm tube and takes the tonearm wires. At random lengths, I epoxy the hourglass washers in place and fill the tonearm with powered cork between the washers. Powered cork adds damping, is VERY light and adds very little mass. I suck with pictures and computers but hope my description is enough to get the idea. Use any variation of the above you want. Good luck !!!
Joe
1. Frank is a VERY skilled machinist / designer with proper machinery that very few people here can match !! Stick to your skill level and be realistic with the results you can obtain.
2. PLEASE , PLEASE stop with the attempted drilling / EDM of the magnets !!!! It is not done in the Reference arm or other arms that i am aware of. It is a total waste of time, energy, machine time, drills etc. Take a GOOD look at some of the arms people actually made !
Some tips :
I used large diameter, precision arrow shafts ( largest legal diameter in U.S.A is .4200". These are round within .0001 for the 31" length. These are 7075 aluminum , hard anodized. There is a brass / aluminum disk (about 3mm thick)that is drilled through to accept the string / knots. This disk is the same diameter as the top magnet and placed in the well on top of the UNDRILLED magnet. I personally made 4 "hourglass" shaped washers 6mm long that are drilled to accept 3mm thin walled teflon tubing. This tubing comes out the back and front of the 10" arm tube and takes the tonearm wires. At random lengths, I epoxy the hourglass washers in place and fill the tonearm with powered cork between the washers. Powered cork adds damping, is VERY light and adds very little mass. I suck with pictures and computers but hope my description is enough to get the idea. Use any variation of the above you want. Good luck !!!
Joe
@hottattoo and jugi63-- thank you both for your replies!
Between your replies and the youtube videos, I think that I can make one these tonearms. Because the photos from back in 2003 are gone, it's difficult to figure how this thing works. I thought at the beginning that the two magnets were placed so that they repelled each other, but now realize that they are mounted North to South so that they are attracted. The string keeps them from contacting each other and the magnetic flux acts as the pivot point. This is usually done with mechanical pivots, such as jeweled pivots on a watch.
So thank you both for the information!
Between your replies and the youtube videos, I think that I can make one these tonearms. Because the photos from back in 2003 are gone, it's difficult to figure how this thing works. I thought at the beginning that the two magnets were placed so that they repelled each other, but now realize that they are mounted North to South so that they are attracted. The string keeps them from contacting each other and the magnetic flux acts as the pivot point. This is usually done with mechanical pivots, such as jeweled pivots on a watch.
So thank you both for the information!
Hi,jugi63
Congratulations !! You are by far the exception with your machining skills !!! However it is Totally unnecessary for the the replication of this tonearm !!! Many people, here, have wasted MANY hours on something that Frank Schroeder does NOT do in the construction of this tonearm. Time is much better spent on the other operational aspects of this tonearm.
Joe
Congratulations !! You are by far the exception with your machining skills !!! However it is Totally unnecessary for the the replication of this tonearm !!! Many people, here, have wasted MANY hours on something that Frank Schroeder does NOT do in the construction of this tonearm. Time is much better spent on the other operational aspects of this tonearm.
Joe
Hi, Duke58
The devil is in the details !!! Once you get the basic concept it not TOO difficult to complete. Precision alignment of the arm components is the key.
Easton X27 Two-Tone Arrow Shaft
Joe
The devil is in the details !!! Once you get the basic concept it not TOO difficult to complete. Precision alignment of the arm components is the key.
Easton X27 Two-Tone Arrow Shaft
Joe
Well, here is a link to my version. Actually this was to demonstrate the DIY arm lifter (also using magnets), but you can shortly see the magnet assembly also.
DIY TT, arm & Lifter in action - YouTube
DIY TT, arm & Lifter in action - YouTube