Spring bolt pulled out

[iceman]

Hey guys.

Yesterday I found that the bolt that the spring attaches to tore itself out of the particleboard dob base. See image below for the one i'm talking about.. obviously this is an older photo before it pulled out.

I'm guessing the best thing to replace it with, is to drill right through and put a bolt through from the inside, and screw a nut on snug up to the base, so the rest of the bolt sticking out can be used to attach the spring to.

Any suggestions or better ideas?

[rmcpb]

Mike,

Before drilling out and bolting it may be worth filling the damage with some epoxy then drilling out and installing one of those flat headed bolts with a large washer each side of the mount and a lock nut. That should hold it and leave enough room on the insede of the mount so your scope does not rub, or hit, the bolt head.

Cheers

[iceman]

Good point Rob, i'll have to be careful to ensure there's enough clearance for the OTA to swing past it without knocking it.

Why would you suggest I fill the hole with epoxy first?

Thanks

[ving]

hey your base doesnt have built in handles!

...or maybe its time to come up with another tentioning device? I generally only use one spring so that i get smoother Alt movement.

[iceman]

I installed (http://www.iceinspace.com/?basemods) those silver handles to help do the crab shuffle when moving the telescope short distances around my backyard. What built-in handles are you talking about?

I never used to have any of the springs connected, lately I'd been tending to connect one of them, and since installing the DSC's I can only use 1 spring anyway because the DSC encoder sits on the other side where the spring used to be.

[rmcpb]

Mike,

I thought to fill the hole so the epoxy soaks into the broken chipboard and restrengthens it so it can handle the future stresses placed on it. Maybe a bit of overkill but very safe and doing it once is better than a nagging problem.

Cheers

[iceman]

Yep good point thanks Rob.

[ving]

sorry heres an explanation... the base on myn, as you can see in the pic has sections cut out to use as handles. Its how i carry it around :)
look above the EP holder
http://img.photobucket.com/albums/v46/ving68/8inch_dob/Dsc03554.jpg

[MintSauce]

I want handles :D

[ving]

you could also screw in a metal (prolly aluminium) plate over the hole and drill a hole thru that to put the bolt thru. if you know what i mean. it'd be pretty strong.
:)

[Brendan]

I have seen velcro strips used as a tensioning device. sorry no pic to demonstrate

[Striker]

Mike ....Telescope abuse......I'm reporting this.....make sure it's repaired and in healthy condition before the inspectors arrive......lol

[vindictive666]

pva a timber glue is good as well that soaks in really well but take a few hours to really set. i used it to put model aircraft kits ( radio control ones) together :)

[rmcpb]

Careful with PVA, it does soak in and would kind of work but is not really a gap filling glue. Epoxy stinks and is nasty but is made for things just like this.

Cheers

[Howzat]

Another less messy solution is to use Selleys Knead-IT (http://www.selleys.com.au/products/live/306/156.asp)

[ving]

hey thats a funky 'tar you got thar howzat! :)

[Howzat]

not as funky as "cows with 'phones" :P

[RAJAH235]

AHHH, go the whole hog and use a 3/8" x 18" long threaded rod thru both sides with big washers & nuts on each side. That way you won't get the uprights spreading, with no danger of the tube falling off the bearings! :P
You won't be able to get much above about 50 degrees tho. but it's easier to reach the focuser whilst sitting!!! :D :P:confuse3:

[ballaratdragons]

This is one of the reasons I suggest making templates of base parts before assembly. Just make a brand new panel out of MDF, pine or marine ply (not chipboard).

Then place a 'Furniture leg' threaded female fitting' on the inside of the panel (not on the outside like you would under furniture).

Or make a complete copy of the whole base out of stronger material.

It may not be a quick fix but it's a better fix.

[MiG]

Has anyone else had the base handle come out? Mine was screwed into t-nuts (the spiked variety that gets hammered into wood, not the ones that go into metal t-slots) which pulled right out as soon as I screwed the handle on.
I replaced the crappy t nuts with a longer bolt that goes through the wood and into a nut and washer.

I can't believe someone thought the t-nuts were a good idea when inserted into crappy (very flaky) chipboard.

[RAJAH235]

Mig, It's called making modifications. T-nuts are O.K.,sort of. The more secure T-nuts have 4??? small holes in them, which enables you to screw them, (not hammer),into whatever material you are using. Nut & bolt is the way to go!:D

[rumples riot]

If you countersink the hole on the inside of the mount, you can then put a larger bolt in that is flush and then make sure you have two nuts on the outside. One to lock off the bolt and the other for the spring to attach behind. This is bound to last a lot longer than a screw into MDF. Or as Ken has said make a new mount out of marine ply. You have all the templates, just might mean you will have to disassemble your mount and cut all the parts.

When I was in the BAS, we made heaps of Dobsonians out of marine ply, and they are still going apparently. That was in 1988.

Just some thoughts.

[rmcpb]

If you contersink the bolt head into the chipboard then it is effectively thinner and weaker. If you are thinking of going this way a new panel would be better.

Cheers

[Starkler]

Mike is now using DSC on his dob where orthogonality of the mount is paramount. Any fabricated bits will need to be a precise match.

[rmcpb]

Maybe a stinky, nasty experience with the really runny epoxy will teach him about the error of his ways. Afterall, telescope abuse is a serious offence :)