PSN-L Message - Subject: Re: Crossed rod hinge/suspensions v/s ball bearings hinge/suspensions

Hi, i am the one who proposed the double shim hinge for a horizonal = sesimometer. However the string method would seem to have less = torsional resistance than the double vertigal shim. Will the = string/filamentsupport the horizontal pendulum 'boom' ? (or will boom = weight allow the vertical vector)gravity allow the boom to dop far = enough to significantly the angle the once horivontal string/filament = enough to increase the angle of the mast end of the pendulum and affect = it's torque? i don't know if increasing the angle will adversely = effect/increase the torque needed to allow easy horizontal motion to the = pendulum or if the arrangement will decrease the needed torque forces to = swing the pendulum. i feel the wire/string/filament will increase the = needed torque to move the pendulum, but this a gut level (no pun = intended) and my track record of being about right about such feelings = run less that 50%. i know my written descriptions are = cryptic at best and probably enigatic at best. i have no way to scan = drawings or post pictures on the net. If someone would send me a snail = mail address and would be willing to scan my hand drawn plans (i did = take mechanical drawing at school in the middle of the last century) and = i would happy send my hand drawn to that person. As a way of = introduction, i am a general practiticaner and my name shoud be in the = 'phone book as 'geoffrey roberts, DO. i'm in Crystal River, FL My work = number is 352-795-2283 or 352-795-5544 or 795-2664, which will be an answering mach. Just leave a number and i'll = return your call. some will answer dr's office or 'may i help you? i mention my only job = to attempt to people at ease about giving me their address. Hopefully = someone will have a post office box that would help perserve their = idenity. <> i am enjoying this post. But i'm fairly busy and = don't have time to build and test each different seisomos. Because of = the time factor i have decided to start with horizontal pendulums. = Thanks for listening. geoffrey roberts, 1035 N Stoney Point <> Crystal = River Fl <> USA. If you're still concerned, you take my 16 and 14 year = old boys as a hostage. i do think you should O'Henry's short story = entitled "The Ransom of red Chief." before you agree to these = conditions. Thank you, Dr. geoffrey roberts, Crystal River 34429 P.S., = After this e-mail, please forget that i'm a doctor and send messages to = 'just geoff.' gr ---- Original Message ----- =20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Sunday, October 23, 2005 11:19 PM Subject: Re: Crossed rod hinge/suspensions v/s ball bearings = hinge/suspensions In a message dated 24/10/05, 1goss@........... writes:=20 Meredith Lamb,=20 Could you post pictures of the rod hinge/suspensions "your setup"=20 This sounds like somthing I would like to try. Hi Bryan,=20 You can get 1/8" tungsten carbide drills (ordinary type) from = www.smallparts.com for $4.20 each. The one that I have is about 2 1/4" = long and half of that is usable shank.=20 I buy the printed circuit board tungsten carbide drills with an = 1/8" shank for a bit under $4.50. I have searched several US websites = for these, but the only one that I found was digikey and they wanted = $7.55 each! The overall length is 1.5" and the shank is 0.9" long.=20 You can also buy carbide spotting drills, center drills and = various router and milling bits, but these are all likely to be more = expensive.=20 You can also try out round 'tool steel', but I would advise = putting a drop of clock oil on the contact point and a paper dust screen = around it. The oil has an 'extreme pressure' additive, which prevents = metal to metal contact. Steel rolling on steel can give rust / corrosion = on the contact point otherwise. Stainless steels are only 'stainless' = because they oxidise very readily, giving a protective surface film. = They don't like chlorides, bromides, iodides or fluorides - and this = includes common salt and perspiration.=20 On a Lehman, I mounted the vertical carbide rod on the support = column and the mating horizontal on the end of the beam. If you do it = the other way around, you may well have to completely reset the centring = and period every time you reassemble / adjust the suspension. I have the = mass offset mounted on the beam with the C of G underneath, to provide = vertical stability and keep the end bearing rod horizontal. Jan Marshall = uses this type of suspension See http://myweb.cableone.net/jandmarshall/ = The wire figure of 8 suspensions that I have tried were made = from 8 thou dia nickel plated mandolin strings, bought from a music = shop. These are piano wire, but are reasonably rust resistant. See = http://www.daddario.com/ The 8 thou piano wire has an 'ultimate = strength' of about 16.5 lbs max. The design working stress might be from = 1/4 down to 1/20 of this, depending on the application. They are a bit = more difficult to set up and adjust than a crossed cylinder and you can = only bend the wire once.=20 Meredith has tried novel forms of these out with considerable = success. My congratulations to him on his patience, dedication and = skill!=20 My ball on a flat suspensions were 5mm stainless steel balls on = a small diamond polished triangular carbide tool bits for a lathe. I = mounted the ball on the vertical support and the flat on the arm, again = to fix the centre of rotation. I was fairly happy with the performance, = since it seemed quite a bit better than a flex foil that I had been = using. I note that www.smallparts.com do sell tungsten carbide balls. I = haven't tried these, but I would expect them to perform as well as the = stainless steel balls. =20 Meredith also tried out cleaned up BIC medium ball pen tips. = These use 1 mm dia carbide balls nicely mounted in a brass holder, but = they are not really suitable for heavy loads. Meredith seemed quite = enthusiastic about these till the tried out the figure of 8 wire and the = crossed cylinder suspensions! =20 Regards,=20 Chris Chapman=20

Hi, i am the one who proposed the = double shim hinge=20 for a horizonal sesimometer. However the string method would seem = to have=20 less torsional resistance than the double vertigal shim. Will = the=20 string/filamentsupport the horizontal pendulum 'boom' ? (or will boom = weight=20 allow the vertical vector)gravity allow the boom to dop far enough to=20 significantly the angle the once horivontal string/filament enough to = increase=20 the angle of the mast end of the pendulum and affect it's torque? i = don't know=20 if increasing the angle will adversely effect/increase the torque needed = to allow easy horizontal motion to the pendulum or if the = arrangement will=20 decrease the needed torque forces to swing the pendulum. i feel the=20 wire/string/filament will increase the needed torque to move the = pendulum, but=20 this a gut level (no pun intended) and my track record of = being about=20 right about such feelings run less that 50%. =20 i know = my written=20 descriptions are cryptic at best and probably enigatic at best. i = have no=20 way to scan drawings or post pictures on the net. If someone would send = me a=20 snail mail address and would be willing to scan my hand drawn plans (i = did=20 take mechanical drawing at school in the middle of the last = century) and i=20 would happy send my hand drawn to that person. As a way of introduction, = i am a=20 general practiticaner and my name shoud be in the 'phone = book as=20 'geoffrey roberts, DO. i'm in Crystal River, FL My work = number is=20 352-795-2283 or 352-795-5544 or

795-2664, which will be an answering = mach. Just=20 leave a number and i'll return your call.

some will answer dr's office or 'may i = help you? i=20 mention my only job to attempt to people at ease about giving me = their=20 address. Hopefully someone will have a post office box that=20 would help perserve their idenity. =20 <> i am enjoying this post. But i'm = fairly=20 busy and don't have time to build and test = each different=20 seisomos. Because of the time factor i have decided to start with = horizontal=20 pendulums. Thanks for listening. geoffrey roberts, 1035 N Stoney = Point =20 <> Crystal River Fl <> USA. If you're = still=20 concerned, you take my 16 and 14 year old boys as a hostage. i do = think=20 you should O'Henry's short story entitled "The Ransom of red = Chief." before=20 you agree to these conditions. Thank you, Dr. geoffrey roberts, = Crystal=20 River 34429 P.S., After this e-mail, please forget that i'm = a doctor=20 and send messages to 'just geoff.' gr

---- Original Message=20 = ----- &n= bsp;=20

From:=20 ChrisAtUpw@.......

To: psn-l@..............

Sent: Sunday, October 23, 2005 = 11:19=20 PM

Subject: Re: Crossed rod=20 hinge/suspensions v/s ball bearings hinge/suspensions

In=20 a message dated 24/10/05, 1goss@........... writes: =

Meredith Lamb,
Could you post pictures of the rod=20 hinge/suspensions "your setup"
This sounds like somthing I would = like to=20 try.

Hi Bryan,=20

      You can get 1/8" tungsten = carbide=20 drills (ordinary type) from www.smallparts.com for $4.20 = each. The=20 one that I have is about 2 1/4" long and half of that is usable shank. =
      I buy the printed circuit = board=20 tungsten carbide drills with an 1/8" shank for a bit under $4.50. I = have=20 searched several US websites for these, but the only one that I found = was=20 digikey and they wanted $7.55 each! The overall length is 1.5" and the = shank=20 is 0.9" long.
      You can also buy = carbide=20 spotting drills, center drills and various router and milling bits, = but these=20 are all likely to be more expensive.=20
      You can also try out round = 'tool=20 steel', but I would advise putting a drop of clock oil on the contact = point=20 and a paper dust screen around it. The oil has an 'extreme pressure' = additive,=20 which prevents metal to metal contact. Steel rolling on steel can give = rust /=20 corrosion on the contact point otherwise. Stainless steels are only=20 'stainless' because they oxidise very readily, giving a protective = surface=20 film. They don't like chlorides, bromides, iodides or fluorides - and = this=20 includes common salt and perspiration.=20
      On a Lehman, I mounted the = vertical=20 carbide rod on the support column and the mating horizontal on the end = of the=20 beam. If you do it the other way around, you may well have to = completely reset=20 the centring and period every time you reassemble / adjust the = suspension. I=20 have the mass offset mounted on the beam with the C of G underneath, = to=20 provide vertical stability and keep the end bearing rod horizontal. = Jan=20 Marshall uses this type of suspension See=20 http://myweb.cableone.net/jandmarshall/=20
      The wire figure of 8 = suspensions that=20 I have tried were made from 8 thou dia nickel plated mandolin strings, = bought=20 from a music shop. These are piano wire, but are reasonably rust = resistant.=20 See http://www.daddario.com/ The 8 thou piano wire has an 'ultimate = strength'=20 of about 16.5 lbs max. The design working stress might be from 1/4 = down to=20 1/20 of this, depending on the application. They are a bit more = difficult to=20 set up and adjust than a crossed cylinder and you can only bend the = wire once.=20
      Meredith has tried novel forms = of=20 these out with considerable success. My congratulations to him on his=20 patience, dedication and skill! =

      My=20 ball on a flat suspensions were 5mm stainless steel balls on a small = diamond=20 polished triangular carbide tool bits for a lathe. I mounted the ball = on the=20 vertical support and the flat on the arm, again to fix the centre of = rotation.=20 I was fairly happy with the performance, since it seemed quite a bit = better=20 than a flex foil that I had been using. I note that www.smallparts.com = do sell=20 tungsten carbide balls. I haven't tried these, but I would expect them = to=20 perform as well as the stainless steel balls.   =20
      Meredith also tried out = cleaned up BIC=20 medium ball pen tips. These use 1 mm dia carbide balls nicely mounted = in a=20 brass holder, but they are not really suitable for heavy loads. = Meredith=20 seemed quite enthusiastic about these till the tried out the figure of = 8 wire=20 and the crossed cylinder suspensions!   =20

      Regards,=20

      Chris Chapman=20

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