Cheap alum obs chair

ericc (Eric) · #1 25-10-2009, 05:42 PM

Hi all-
FYI-if anyone else is interested in a rainy day project?
While waiting for my new scope,I made a nice and light alum observation chair.The designs were copied from the other home made jobbies posted on the net.

Bunnings has the correct length alum square tube availible(minimal cutting is reqiured) and the fasteners etc,but the tread grip was $29---ouch!

I had some of the other bits and pieces laying around the house,that I used.

Prolly cost $90 or so to build.

Took 8 hrs + to make(bit of trial and error--with no actual plans as a guide)

I think it will be very stable?

The seat slides up and down easy.It holds very firm when you sit on it.I have not noticed any slippage at all.From max to min extension everything is good.I weigh 70 kg.

Cheers-Eric

Heres a pic--if I can figure out how to post!!

erick (Eric) · #2 26-10-2009, 09:29 AM

Looks like a nice piece of work, Eric.

Now you have worked out how to attach pics (

), how about a close up on the support mechanism for the seat - why is the non-slip required?

Mr Moderator may even move this into DIY & ATM where it would have a better home.

ericc (Eric) · #3 26-10-2009, 10:48 AM

Thanks for the positive feedback Erick(you must be nice guy with that name)!
Yeh --Im very happy how it turned out.
I used the tread grip on the front of the uprights and soft rubber radiator hose on the "seat pinch" for that extra security?
This enables the seat to be moved up and down really easy,without the need to lock up the wingnut, when at the desired height.

IE:move it up and down and just sit on it--and everythings good!

I will post another couple of pics for clarity.
Thanks again,
Cheers-Eric

ericc (Eric) · #4 26-10-2009, 03:36 PM

More pics!

Dennis · #5 26-10-2009, 04:20 PM

Hi Eric-of-the-chair,

Nice job, I like the design and finished product. However, in my wardrobe, I have a pair of tracksuit pants and a flannelette shirt with parallel lines of abrasions and tramway lines of material missing from when I made a similar chair several years ago.

The seat managed to slip one night; fortunately, it was during winter when I had thick layers of clothing between my back, backside and the non-slip abrasive stick on strips!

Cheers

Dennis

erick (Eric) · #6 26-10-2009, 04:23 PM

That's a neat design. Thanks for the extra pics.

Dennis · #7 26-10-2009, 04:25 PM

I just found a couple of photos of my now deceased model!

Cheers

Dennis

ericc (Eric) · #8 26-10-2009, 05:45 PM

Yep Dennis---a very valid point---Hmmm ,I didnt think of that one---OUCH!!!!
Back to the drawing board perhaps??
Cheers-Eric

Dennis · #9 26-10-2009, 07:03 PM

Quote:

Originally Posted by ericc

Yep Dennis---a very valid point---Hmmm ,I didnt think of that one---OUCH!!!!
Back to the drawing board perhaps??
Cheers-Eric

Hi Eric

Your design may reduce the risk of this, as my original design had anti-slip on anti-slip which made it a bit rough trying to adjust the height. So, I removed the anti-slip from the floating seat, leaving x 3 wooden surfaces (approx 2x5 cms each) to bear against the anti-slip on the x3 inclined legs.

I noticed that over a few months, shallow grooves had begun to appear on the three off (2x5 cms) wooden bearing surfaces on the seat and perhaps this contributed to the fateful slip one dark night?

Your design and use of what looks like thick rubber pads may lessen the risk of slippage, although I would keep and eye on wear and tear in this region – just in case!.

Hope you enjoy the use of your chair; it looks fabulous and I’m sure it will be a real joy to use – I certainly enjoyed mine.

Cheers

Dennis

Dennis · #10 26-10-2009, 07:08 PM

Here is the later incarnation, using notches routed out in the legs which engage a steel rod. Not as smooth or infinitely variable, but very solid now.

Cheers

Dennis

PS – the hinged wooden back was my initial response to preventing any further back scratching from the aggressive anti-slip strips!

ericc (Eric) · #11 26-10-2009, 07:59 PM

Thanks for taking the time for the tips Dennis,I can now see where the fixed notching is alot better than just friction alone.

And yes,I did choose really soft rubber(a new radiator hose I had kicking around)to ensure heaps of grip.

I will watch out for any signs of wear etc--but I think a modified version will be on the way before too long--as we all know about Murphys Law!

Thanks again for the advice (and the pics)--as it would never have crossed my mind to consider gravel rash, from a malfunction!

Cheers-Eric

Dennis · #12 26-10-2009, 08:21 PM

Quote:

Originally Posted by ericc

Thanks for taking the time for the tips Dennis,I can now see where the fixed notching is alot better than just friction alone.
And yes,I did choose really soft rubber(a new radiator hose I had kicking around)to ensure heaps of grip.
I will watch out for any signs of wear etc--but I think a modified version will be on the way before too long--as we all know about Murphys Law!
Thanks again for the advice (and the pics)--as it would never have crossed my mind to consider gravel rash, from a malfunction!
Cheers-Eric

Hmm, I dunno? The notches were a real pain to cut out, even using a router. If you inspect the rubber hose on a regular basis and fit a protective back to the seat to take the abrasion should anything slip, then I’d probably leave it at that until you have done further testing.

As soon as I had the seat slip on mine, I effectively banned 3rd parties from using the chair and also fitted the protective back and didn’t have any further slips. I just got bored one weekend so modified the design by routing out the notches.

Great stuff this DIY eh!

Cheers

Dennis

spearo (Frank) · #13 28-10-2009, 05:48 AM

great designs Eric and Dennis
this finally clarifies the concepts in my head (i have a part at home i keep looking at thinking about converting to such a chair but couldnt figure out how)
very helpful
thanks
frank