In the pic below, the shaft is narrowed on the left so that it fits the hole on the narrow end of the barrel. This acts as a guide so that the shaft doesn't have unnecessary play. Note the two nuts on the other end. The larger is filed to snugly fit the inner diameter of the barrel. Together with the hole at the other end, this also serves as guide to the shaft and avoids play in horizontal plane.
I think the trick to getting a damped lift and drop is to have a tight fit of the narrowed portion of the vertical shaft and also similarly tight fit of the large nut within the barrel. Tight as in tight tolerance fit so that there is some amount of friction to resist the vertical shaft from moving freely. I think it's worth trying out this idea
Hi,
What ever part are in friction you can lubricate it with thick silicon oil. So you will get smooth lowering/lifting action. The easiest tonearm lift I have seen was in cheap Garrard TT which uses two plastic disc separated by plastic film and with thick oil. It had screw to tighten which controlled the speed of lifting.
Regards.
What ever part are in friction you can lubricate it with thick silicon oil. So you will get smooth lowering/lifting action. The easiest tonearm lift I have seen was in cheap Garrard TT which uses two plastic disc separated by plastic film and with thick oil. It had screw to tighten which controlled the speed of lifting.
Regards.
Hiten and Doug,
I've thought about oil damping but found it challenging as the holes through which the cam shaft passes into the barrel needs to be sealed with some sort of gasket. I've recently taken apart the lift mechanism of a Technics SL-D5 changer. I think it works on the friction principle. I didn't have a clue when I took it apart, but on hindsight, that seems to be the case. Today I was waiting impatiently for a friend, when the thought suddenly struck me. There is no oil damping, and it works quite well. The thought also struck me that the fit needs to be very good, so I think I'll pay a visit to my favourite machinist with a drawing, as this is clearly beyond my limited skills and tools available on hand.
I've thought about oil damping but found it challenging as the holes through which the cam shaft passes into the barrel needs to be sealed with some sort of gasket. I've recently taken apart the lift mechanism of a Technics SL-D5 changer. I think it works on the friction principle. I didn't have a clue when I took it apart, but on hindsight, that seems to be the case. Today I was waiting impatiently for a friend, when the thought suddenly struck me
. There is no oil damping, and it works quite well. The thought also struck me that the fit needs to be very good, so I think I'll pay a visit to my favourite machinist with a drawing, as this is clearly beyond my limited skills and tools available on hand.Well, I've got your arm working and its really impressive. Considering it costs pennies, the sound is pretty damn good. This is using a cheap crap Garrard SP25. The cartridge is a Shure M75ED. Compared with my usual TT, the bass is not quite so well defined but the upper registers are just stunning.
Inspired by the long arm, I made a more conventional arm this morning. As I'm breaking up some old hard disks, I wondered how the motors would be a the horizontal bearing. The answer is superb.
Quick bit of work on the lathe with some boxwood and we have the basis of another reasonably cheap arm.
An externally hosted image should be here but it was not working when we last tested it.
Inspired by the long arm, I made a more conventional arm this morning. As I'm breaking up some old hard disks, I wondered how the motors would be a the horizontal bearing. The answer is superb.
An externally hosted image should be here but it was not working when we last tested it.
Quick bit of work on the lathe with some boxwood and we have the basis of another reasonably cheap arm.
An externally hosted image should be here but it was not working when we last tested it.
Looks fine to me. The female part in mine is just the indentation left in the top of the shaft from drilling the entry hole for the nib into the tone arm. It's nice and snug, and doesn't allow the pen nib to jump out easily even when using the arm lift.
New and improved shaft with new and improved spring and new and improved brass "nut"
The brass nut is machined to tightly fit into the barrel. It is 3 mm thick with about 1.5 mm groove.
Greasing: the narrow but deep groove will (hopefully) serve as a grease depository.
Corrected hole for the bamboo lift lever. Now lift and drop directions are correct:
The friction provided by the brass nut required a stronger spring. I found out that there is a minimum spring strength to overcome the friction of the brass nut against the inside surface of the barrel. This involved stretching or compressing the spring length to get just the right amount of repulsion. I started out with a tightly coiled spring, so I had to stretch it to get desired length. As it stretches, the spring became stronger.
Well that's the theory. Now to mount and check if it will drop the stylus gently. I have a feeling the spring may need some more tweaking as it will have the added weight of the arm compressing it.
The brass nut is machined to tightly fit into the barrel. It is 3 mm thick with about 1.5 mm groove.
Greasing: the narrow but deep groove will (hopefully) serve as a grease depository.
Corrected hole for the bamboo lift lever. Now lift and drop directions are correct:
The friction provided by the brass nut required a stronger spring. I found out that there is a minimum spring strength to overcome the friction of the brass nut against the inside surface of the barrel. This involved stretching or compressing the spring length to get just the right amount of repulsion. I started out with a tightly coiled spring, so I had to stretch it to get desired length. As it stretches, the spring became stronger.
Well that's the theory. Now to mount and check if it will drop the stylus gently. I have a feeling the spring may need some more tweaking as it will have the added weight of the arm compressing it.
+1 to ecodan.
The taper of the male bearing should be narrower than the female by, say 15-20 degrees. This will give the arm sufficient room to wiggle in both the vertical and horizontal planes without being restricted while avoiding being toppled over easily. The pivot point - the point where the male and female meet, must be slightly above the axis of the arm tube. So make the hole for the female bearing accordingly.
The taper of the male bearing should be narrower than the female by, say 15-20 degrees. This will give the arm sufficient room to wiggle in both the vertical and horizontal planes without being restricted while avoiding being toppled over easily. The pivot point - the point where the male and female meet, must be slightly above the axis of the arm tube. So make the hole for the female bearing accordingly.
I made some more improvements to the arm lifter as I quickly realised that the thin wall of the pen cap barrel is not going to be strong enough to take on the pressure of screws that will be used to hold it in place on the wood board. Note the holes on the side of the wooden support - they're threaded, and will allow M4 screws to grip the arm lift. There is no threaded hole in the barrel so the height of the arm lift will be adjustable as needed. So here's the new barrel, made of thick brass pipe.
Assembled:
I've calibrated the spring as best as I could. The drop is now deliberate but I would have wanted something that drops gently by itself once the lift lever is lowered.
I have also made a new cam shaft with larger diameter rod so that the amount of lift increases slightly from about 2 mm to about 2.5 mm. I've also realised that the cam shaft can be much shorter. Need to rework it.
Assembled:
I've calibrated the spring as best as I could. The drop is now deliberate but I would have wanted something that drops gently by itself once the lift lever is lowered.
I have also made a new cam shaft with larger diameter rod so that the amount of lift increases slightly from about 2 mm to about 2.5 mm. I've also realised that the cam shaft can be much shorter. Need to rework it.
Silicone oil damping
I haven't tried any form of oil damping yet, Doug. I would really love to be able to get just the right amount of friction between the inner surface of the barrel and the thick washer/ring that's attached to the shaft that moves up and down. The friction, coupled with just the right amount of spring action, I feel, can get a very well-damped drop. To this end, I have changed the brass washer/ring shown in the post above (the one that stops the spring) to a teflon ring. The brass is 3 mm thick. The teflon is 6 mm thick to have more suface area for friction, and still sports a cut groove to act as grease reservoir. I have put it together and tuned the spring as best as I could. Unfortunately the drop is not yet as damped as I had envisioned. I will work on it some more. I think I figured out why, too. The barrel's inner diameter was enlarged with a drill bit on a lathe, then smoothened manually with fine sandpaper while rotating the barrel on the lathe. I have a feeling the sanding ended up imparting slightly irregular inner diameter, leading to a not-too-smooth movement for the shaft inside. I'll have to look for a ready pipe (without the need for further boring/reaming or sanding) with tight inner diameter tolerance, so that at least one variability is eliminated.
BTW, did you make one with silicone oil damping? If yes, how do you prevent leaks?
I haven't tried any form of oil damping yet, Doug. I would really love to be able to get just the right amount of friction between the inner surface of the barrel and the thick washer/ring that's attached to the shaft that moves up and down. The friction, coupled with just the right amount of spring action, I feel, can get a very well-damped drop. To this end, I have changed the brass washer/ring shown in the post above (the one that stops the spring) to a teflon ring. The brass is 3 mm thick. The teflon is 6 mm thick to have more suface area for friction, and still sports a cut groove to act as grease reservoir. I have put it together and tuned the spring as best as I could. Unfortunately the drop is not yet as damped as I had envisioned. I will work on it some more. I think I figured out why, too. The barrel's inner diameter was enlarged with a drill bit on a lathe, then smoothened manually with fine sandpaper while rotating the barrel on the lathe. I have a feeling the sanding ended up imparting slightly irregular inner diameter, leading to a not-too-smooth movement for the shaft inside. I'll have to look for a ready pipe (without the need for further boring/reaming or sanding) with tight inner diameter tolerance, so that at least one variability is eliminated.
BTW, did you make one with silicone oil damping? If yes, how do you prevent leaks?
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You need the silicone as in the video.
https://www.youtube.com/watch?v=o9BNoKM_Glc
Or you may buy it from here
Silicone Damping Fluid For Tonearm Cueing Mechanisms, Damping Troughs and Monopivots
https://www.youtube.com/watch?v=o9BNoKM_Glc
Or you may buy it from here
Silicone Damping Fluid For Tonearm Cueing Mechanisms, Damping Troughs and Monopivots
Arrow question...
Just jumping in...been reading this thread with great interest. I hope what I am asking hasn't been answered already. If so, apologies. I looked into the Easton Gamestopper arrow (recommended by Stew) only to find that there are a number of different "gamestoppers." There is a 500, and a 400, and 300, etc. I understand the differences have to do with diameter and wall thickness. Which one is the preferred one for the 219 tonearm? Thanks for the help!
Just jumping in...been reading this thread with great interest. I hope what I am asking hasn't been answered already. If so, apologies. I looked into the Easton Gamestopper arrow (recommended by Stew) only to find that there are a number of different "gamestoppers." There is a 500, and a 400, and 300, etc. I understand the differences have to do with diameter and wall thickness. Which one is the preferred one for the 219 tonearm? Thanks for the help!
I'm not sure it's absolutely critical. The whole idea is to make a high quality tonearm from scraps found around the house. I got mine from a bin at the local archery range, it's a little smaller in diameter but sounds great. After all we're all using different cartridges with different compliances, therefore there is no one size fits all anyway. My 2c
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