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Is there an engineer in the house?

Moonshane

By Moonshane
in DIY Astronomer

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Moonshane

Moonshane

Posted
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Hi all

I would like to find someone that could turn a straight rod on a lathe for me and wondered if there are any SGL'rs that can do such work?

it's for my equatorial platform and needs to be around 12" long, with an M10 thread most of the length and with a 6mm hole bored into the centre of one end (about an inch deep) and an M4 tapped hole (into the threads) at the same end, and an 8mm shaft about an inch long at the other end. I can supply a drawing but wondered if anyone could do this? and confirm approx costs etc?

I suppose there's no reason why a standard straight M10 threaded rod could not be used (and I have a stainless rod that might do) but open to ideas.

Cheers in advance

Shane

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Moonshane

Moonshane

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I have sussed a different way to do this I am just going to epoxy a nut on the end of the M10 thread and tap this with M4.

I can then either grind down or get someone to machine the end down to 8mm. if anyone can do this for me please it would be greatly appreciated.

cheers

Shane

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Adamski

Adamski

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you can buy stainless or mild steel (zinc plated) threaded bar from any steel stockists and fastening suppliers for not much money, normally in a 1m length tho, or maybe look for a steel fabricators and get an offcut.

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johninderby

johninderby

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I have sussed a different way to do this I am just going to epoxy a nut on the end of the M10 thread and tap this with M4.

I can then either grind down or get someone to machine the end down to 8mm. if anyone can do this for me please it would be greatly appreciated.

cheers

Shane

Hi Shane

Would this do?

I had an off-cut of M10 threaded stainless rod so I just turned down one end to 8mm.

John

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Moonshane

Moonshane

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what kind offers - thanks guys!! I was with another SGL member this afternoon (George) and he suggested another solution for my problem which is a further support nearer the end point. this might just reduce the 'wavering' in the rod and ensure it runs a bit smoother.

I may still take you up on your offers shortly but perhaps this might work too.

I'll update in due course.

cheers

Shane

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Peter Drew

Peter Drew

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You have to be a bit carefull if you are using stock threaded rod for a precise purpose. The quality seems to depend on whether it has been produced by rolling or the use of a die, the latter can sometimes have the thread a bit eccentric to the core material which can introduce periodic error even if the rod is well centered in the lathe on the thread crests before turning any details.

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Moonshane

Moonshane

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You have to be a bit carefull if you are using stock threaded rod for a precise purpose. The quality seems to depend on whether it has been produced by rolling or the use of a die, the latter can sometimes have the thread a bit eccentric to the core material which can introduce periodic error even if the rod is well centered in the lathe on the thread crests before turning any details.

cheers Peter

I agree it's important to buy good quality rod. whilst they may be a very little amount of shift at higher mags, my main problem currently is with the rod connectors I bought which seem to have been made with low quality tolerances; for for the job of joining rod together on e.g. a building site but not for this purpose. there's quite a degree of side to side movement. using the turned rod kindly supplied by John will sort this issue out and I expect will make a substantial improvement to the accuracy of the EQP - it's only for visual and I am already using at at 400x + with good results, it's just that the target drifts from one side of the view to the other and back again as the rod connector turns it's circle!

hi peter

i'v been using treaded rod for years on various projects over the years and never had problem

but i'm not saying your wrong of course each to there own as thay say whoever thay are

I think it's down to the usage really. mine is visual only and not as critical as AP.

Shane

The stainless rod I use is:

Threaded Bar Grade A4 316 Grade Stainless Steel (BS 970 Gr 316S31/303S31)

Not the cheapest but I've never had the slightest problem with it.

John

cheers John

I am sure it will be good quality. The rod I sent you in return also seems good, it's just that I needed to reduce it to 8mm to go through a skate bearing at the far end and this is where the rod connector was not too true. your turned rod will be a massive improvement.

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