DIY Stands-Standanddeliver? i Stood, hope i delivered

[keith_correa]

Correct me if i am wrong - Steel pellets for filler will not dampen the sound waves .. they might resonate ... and the sound might have a metallic quality.

I've heard a sewer pipe effect from plain iron stands not filled with sand.

Regards

I think alternating sand with steel pellets might be a good idea provided the bottommost and topmost layers are pure sand. Steel pellets will provide mass and sand will seep between the spaces between the pellets anyways. Might be overkill but wtf? Now if there were to be rubber tubing lining the inner walls of the pipe [stand]... Killer stands!

 

[rallynut]

magma,absolutely great going on the stands.look damn cool,and being a stickler for detail shows .love the spikes and collar.very neat.cheers

 

[magma]

Correct me if i am wrong - Steel pellets for filler will not dampen the sound waves .. they might resonate ... and the sound might have a metallic quality.

I've heard a sewer pipe effect from plain iron stands not filled with sand.

Regards

i think keith has explained well what i plan to do

Stealing Chowpatty sand is always a good idea :lol: Just make sure you wash it well in Dettol laced water and dry it really well before you use it. Better get started soon because according to the met. dept. the monsoon will hit Mumbai in 4 days so what with this heat that we have here - drying sand will be a matter of hours now.

hmm detol laced water. didnt think of that.thanks for the up
BTW is taking sand from chowpatty allowed or i really have to steal it?

Actually I meant damping between the granite base and the collar - with some rubber bushing - maybe.

yes thats very possible.actually i shud have done that
but what happened wa when i made the spikes i had a miscalculation on the lenght of the threads.they got short. i coudnt even spare 2mm to adjust a wiser.
Maybe ill make some more spikes later on
once again thanks for the idea keith.i should talk to you during my next DIY

I think alternating sand with steel pellets might be a good idea provided the bottommost and topmost layers are pure sand. Steel pellets will provide mass and sand will seep between the spaces between the pellets anyways. Might be overkill but wtf? Now if there were to be rubber tubing lining the inner walls of the pipe [stand]... Killer stands!

WOW you have read my mind. im trying to get that rubber lining done but silicone coating on the inners of the pipe is provin to be difficult.
im looking at simpler options likejust rolling a silicone sheet and pllacing it inside and then putting it ina powder coat baking oven,the silicone most probably will stick to the inners
other ideas are very welcome

magma,absolutely great going on the stands.look damn cool,and being a stickler for detail shows .love the spikes and collar.very neat.cheers

thanks for the encouragement man.


@cranky
thank you very much for the approval.
my speakers weigh in at only 12.5 pounds each
which is not much hence ive not planned for the balls on the top plate.
you are right for the balls to do their job large mass is reqd.
i thought of just having a granite skirting with antislip silicone feet

 

[heliumflight]

Magma I truly salute your DIY spirit:thumbsup:

 

[dinyaar]

Hi,
Good work boss. It will turn out superb.

Ali, last year i went to chowpatty and took two bags of sand and was peacefully walking to my car when a cop from the chowki there stopped me and accused me of theft!!!!!!!!! I explained the purpose and was really embarrased and finally just paid him Rs 100 to cut it short. So i guess u will have to be discreet.

BTW has the amplifier and DVD p arrived?
Rgds

 

[magma]

Hi,
Good work boss. It will turn out superb.

Ali, last year i went to chowpatty and took two bags of sand and was peacefully walking to my car when a cop from the chowki there stopped me and accused me of theft!!!!!!!!! I explained the purpose and was really embarrased and finally just paid him Rs 100 to cut it short. So i guess u will have to be discreet.

BTW has the amplifier and DVD p arrived?
Rgds

wow
that means i have to actaully steal it!
crap
i might have to go to the glass walas then.

still waiting on the amp and oppo
the amp should be here shortly i hope!

hey dinyaar
no inputs onthe stand
you think i should add steel balls and sand or just leaveit at sand
( i already have the steel pellets and balls)

 

[venkatcr]

Ali, last year i went to chowpatty and took two bags of sand and was peacefully walking to my car when a cop from the chowki there stopped me and accused me of theft!!!!!!!!! I explained the purpose and was really embarrased and finally just paid him Rs 100 to cut it short. So i guess u will have to be discreet.

Stealing sand from a beach which is God's gift to humanity? My god these cops have some nerve. I would have challenged him to show me the rule book that says you can take some sand from the beach for personal use. But as you say, you don't want an embarrassing situation. In TN and other places, contractors happily empty river beds even when they have court orders restricting them. This was also shown in the movie 'Dasaavatharam'.

Cheers

 

[dinyaar]

Hi Ali,
Just stick to using the sand. Proven benefits. Rest of the WIP seems very good truly.
Get the sand from chowpatty but clean and dry it completely. Very imp as it can stink later and attract all kinds of unwanted pests.
I found an IC which will work for u. Its basically a DIY from Kimber 4 VS speaker cable and must be pretty old. If u like it use it till u feel the urge to explore some branded stuff.
Rgds

 

[magma]

np magma. I envy you guys who have access to good machine shops, they really help..

if you need anything ill be happy to help

Two quick points, though I know they're probably coming in late but what the heck.

I would use less of the steel spheres, just as many as will be able to take the weight of the entire mass without compressing. It may not be necessary to use all of them. The idea is to reduce the surface area and increase the compressive tension on the whole stand. You may find this beneficial.

.

i didnt understand please explain
i have steel spheres about 10mm in dia and also steel pellets cylinders that are 4mm in dia and 8mm long.
i thought i using these for 1/3rd of the column and the rest 2/3rd sand to make it bottom heavy

Second, I would use three spike/collar assemblies, not four. I have seen some variation in three versus four support points, and find that three generally makes the assembly tolerant of variations in floor geometry and flatness, as well as further improve stability. Of course, the added reduction in contact area also helps a lot. I know you've already drilled your plates through, but I would suggest trying an additional hole at the rear center position to experiment. If you don't like it all you have to do is use one of those pretty caps to cover it up.
.

crankyjiii
you really should have told me earlier
justkidding
i learnt the hard way
levelling 4 is more difficult than leveeling 3 too!

actaully as ou say i can still drill a hole and do the triple spikes.
i will try that later though

Last (I know I said two) I would not use silicone. I found them to have a very adverse effect on the sound. My BE-718 came with silicone pads for coupling to the stand, and I experienced either a flabby midbass when the coupling was loose (the stand comes with bolts to secure the speaker) or a tense, harsh upper midrange when the coupling was very tight. Tuning it was a matter of patience, and I feel that a rigid coupling will produce better results, even if you don't use bolts. Somehow, I think reverse spiking the top top plate and resting the speaker on the tips is a much betttr idea.

I don't know how far along you are, but some fiddling around may be productive.

i thought of just usingthe granite skirting and either placing the speakers on them directly
or using the silicone pads and STICKING ( feviquick) them permnently to the granite skirting and then placing the speakers on these

now though i can easily makes spikes and collars for the top plate(actaully i think i already have a few leftover) i did not want to use this option only for 1 reason
i have a 2yr old in the house
spikes will offer no friction and the speaker may get dislodged even with a nudge

hence ive thought of silicone. at least its a little anti skid

please provide your inputs

 

[magma]

cranky

hmm now i undertand
thanks for spelling it out
reduce point of contact

yep, if you need anything pls do feel free to ping me

 

[keith_correa]

These may seem to be "Duh" questions:

I would use less of the steel spheres, just as many as will be able to take the weight of the entire mass without compressing. It may not be necessary to use all of them.

1. How would you gauge how many steel spheres to use. Is there a formula to use?

The idea is to reduce the surface area and increase the compressive tension on the whole stand. You may find this beneficial.

2. The answer to the first question may be the answer to this too:
Take the weight of what entire mass? How will one know/figure that it will?
Without compressing what?

 

[magma]

you guys should note that NOT ALL balls may be in contact with the granite base due to uneveness in grinding!
grantie slabs arent ground on a CNC you know
(ive not actaully checked the above- im just assuming)

 

[keith_correa]

Good questions, not 'duh' at all keith.

Each ball will be made of a metal whose tensile properties are readily available (I assume, else we can use the number for regular poured steel). The weight that each sphere can take is easily calculated by using a formula (I don't have it with me, but we did it in Class X physics). The resulting number is the weight beyond which the sphere will compress (physically).

Divide the weight of the stand by 3 (the number of spikes) and then by this number, to find out how many balls you need.

Also explains why I nearly flunked Class X by getting 36/100 in Science - or was it Math

 

[magma]

Good point again, magma, so may I suggest using a thick (~6mm) metal washer between the base and the spheres to ensure even contact. I would assume that any loose spheres would resonate sympathetically and become a bigger problem.

The washer may be permanently epoxied to the granite base, this would not necessitate a change in design, just a handful of extra washers and some (~6mm) added height.

already done!
however its a nylon washer to stop any vibrations
i think keith suggested this earlier too

Well, at least you pushed me to get off my lazy ass and research it. The correct index is the Rockwell hardness index, a number that indicates the ability of a given metal to bear load before compressing/deforming.

I did this a long time ago (>20 years), but IIRC we got about 100kg static load for a truck gearbox bearing (single sphere off the bearing) that was 8mm in diameter. It would be different for different metals and different manufacturers. Those were Timken bearings, IIRC, some of the world's best. I don't remember the Rockwell index, but i guess it would be in the 50+ range. We used a vice to apply the load, and a fancy little device to measure the loading tension.

i used to use a lot of these calculations rockwell/stress tests failures etc
This does help a lot when you have fixed budgets and have to save on materials ( so that you maxiimise gain with minimum matl)
however over the years we found this process cumbersome and we like doin it just by experience now.
we also apply FOS with experienc eonly.

 

[prasen_b]

ooo

i didnt think that was so cheap.
i should ask my glass guys
thanks for the help.much appreciated

i have already arranged for steel pellets which i plan to fill 1/3rd
for sand i was gonna steal some from chowpatty!:licklips:

i didnt know you could get sand for this purpose
where did you get it from(are you in mumbai?)

I am from pune, just for reference in pune u can get it from shops near phoolwala chowk in ravivar peth . Mostly the glass walas get if from some wholesale trader. You can get it directly from them. The quality and fineness of the sand is very good, so I would say its worth it. I had used the sand to fill like a 4x4 inch column made of commercial plywood and it provides very good damping. Since the top plate is removal you can always try different combination of fill.

 

[magma]

now below is a pic of a black rubber cap
initially i had thought of getting these custom caps made

they are supposed to fullfill 3 function
a) the ID fits into ID of pipe and the OD is likewise. a hole of the diameter of the bolt would be drilled i between. this allows any movement of the pipe realtive to the top and bottom plates
b) to serve as damping and antifriction between the SS pipe and smooth granite slabs
c) to act as a soft washer so the granite does not crack when the nut is tightened

now the above can be made with various materials howeveri had access to only delrin,PU,nylon,silicone and rubber
Delrin and nylon were ruled out because though they were good for the first function they were not for the rest
Silicone custom made is just waaaay to expensive
that left rubber

Hoever due to some circumstances i could not get just 4 pieces custom made

Alterantively i thoughti could get a steel disc machinedtotheID of my column to take care of the first function but my lathe operater went to Gaaoo and i have been a little unwell so ididnt want to operate the lathe

 

[magma]

i had to get a little innovative now,

the following is waht i came up with
and actaully im happier with this

below is a pic of some custom washers
the white rings are delrin-toserve the 1ST function
the darker red SILICONE gaskets are to serve the 2nd
the softer PU washers ( transparent ) serve the last function

 

[magma]

below are pictures of PVC sheet and the SS tubes that will be used as the central column
the SS tube is grade 304 and is 5 mm thick and approx 63mm OD

The PVC was cut to size and a roll was placed inside the SS tube and put in a baking oven .
the heat caused the PVC to get soft and stick to the insides of the pipe ,
Basically forming a PVC coating.
A knock test gave me very satisfactory results

Buffing will be done to give a cool Matt SS finish that you can see on stands that Quad ususally sells

 

[magma]

picture below show a mock assembly
the firstpicisof the bottom of the base plate with a nylon washer
the same assemble will be seen on the top face of top plate, except a check nut willbe used instead so as to keep the height as low as possible

the second and third pick shows the top side assembly of the base plate
the tube will rest on the gasket and the delrin ring which has been machined to the exact sizeof the ID will ensure no realtive movement
The same assemble will be repeated at the bottom of the top plate

 

[magma]

heres the pic of the steel balls and steel pellets

NOw this is still where im in two minds :sad:
should i use these or should i just use sand

ALSO i have an UNFORTUNATE point to post
it seems that i as a member here have only about 225-250kb of total attatchement space in hi fi vision.
i have already expired that with this post

that probably means i can post no more photos.
i hope the modcan do somethin about this.
im not posting for my personal gain or selling anything i justthought of contributing to a forum which has already given me so much