Need some technical advice - the FeatherTouch on my APO has come loose, and I see one of the previous owners had used an incorrect allen key and "stripped" the cap screws, making it impossible to tighten.
I need to replace these puppies, but I'm not sure what specifically to order (thread size, cap size, thread length, etc).
Anybody have any tips on what the technical specs for this screw are? And possibly a supplier in Australia to source them>
The thread is about 10mm long, and the allen key is I think 2 or 3mm, but it's difficult to say, given it's now almost circular.
I'd just go to Bunnies. They're too expensive but if you only want a few it's better than going to a specialist supplier and have to buy a box of 100. They also have a panel with nuts mounted on it so you can match the thread. Then just measure the length and see if you can get a match.
No don't go to Bunnings , they will not have the correct screws in stock because being USA made they will be an SAE thread in imperial size ( different again to the English UNC/UNF threads , but the same diameters ) , Bunnings don't stock SAE and the person you deal with will probably look at you like you are from another PLANET .. .
I know this because I had a FT focuser and my made in the USA CI-700 mount is all SAE as well .
It looks like someone forced a close metric bolt in , has it damaged the focuser threads ? .
Any good machinist will have the gear to measure the thread and point you onto a good supplier , they will sell small lots if you take the focuser with you .
Good luck .
Brian.
ps. you will need an imperial allen key set as well
No don't go to Bunnings , they will not have the correct screws in stock because being USA made they will be an SAE thread in imperial size ( different again to the English UNC/UNF threads , but the same diameters ) , Bunnings don't stock SAE and the person you deal with will probably look at you like you are from another PLANET .. .
Sorry, I thought Bunnings would stock SAE. They did the last time I noticed. Looks like a trip to a specialist supplier.
The quality of sales advice does vary considerably. At my local store I have my preferred 'victim' if I need advice. Older chap, possibly a tradie who has got off the tools, seems to know everything and would certainly know SAE. You're right though about some of the casuals - wouldn't know left-handed screwdrivers from striped paint.
Where are you?
There are a number of fastener suppliers around Melbourne.
There is one in Coburg North that I go to from time to time at 89 Newlands road called Newlands Fasteners.
If you take the old screw along they will tell you the size and supply replacements. One that size will cost about $1.
being USA made they will be an SAE thread in imperial size ( different again to the English UNC/UNF threads , but the same diameters )
If they are US made, they will more likely be UNC/UNF.
( IIRC, SAE is effectively replaced by UNF for "general purpose" bolts like this )
The English ( and us ) use mainly true Whitworth thread for these smaller dia general purpose bolts, and in that case, Whitworth and UNC are "effectively" interchangeable for dia/pitch, but have a different thread angles.
As such, the test board at Bunnings should be able to confirm the thread pitch and dia.
If they are true UNC, then as noted above, they may have a different thread angle to whitworth, and the numbering system for anything less than 1/4" also changes to a "gauge" based nomenclature.
Ref https://en.wikipedia.org/wiki/Unified_Thread_Standard
ie Below 1/4" the UNC bolt dia is defined by a gauge, not a fractional dia ( like you would see on a Bunnings Blister pack )
So for UNC fasteners, we get 1/4-20, then 12-24, then 10-24, then 8-32.
vs say 1/4, 3/16, 1/8 etc
The specialist suppliers do stock these true UNC sizes, whereas Bunnings etc dont.
( CostLess Bolts in Moorabbin has pretty much all of these sizes in SS, and is where i get most of mine from )
They don't stock them here in Rocky or Port Kennedy Bunnings here in WA , yes they do sell a few , a very few small machine screw SAE sizes but only up to the 10/8 gauge sizes , hardly used any more ' .
Seems the eastern state Bunnings gets a better supply .
Oh well , least I ain't in Darwin anymore ,, its way worse up there '
Brian.
ps , I did get a new bubble for my spirit level in Bunnings Darwin ......
Quote:
Originally Posted by AstralTraveller
Sorry, I thought Bunnings would stock SAE. They did the last time I noticed. Looks like a trip to a specialist supplier.
The quality of sales advice does vary considerably. At my local store I have my preferred 'victim' if I need advice. Older chap, possibly a tradie who has got off the tools, seems to know everything and would certainly know SAE. You're right though about some of the casuals - wouldn't know left-handed screwdrivers from striped paint.
Yes they have , but the confusion is still there , I left out 'BSW' for this reason ( 1/2 BSW and 1/2 UNC are the only size under 1 inch that match , the rest have a different included pitch angle ) , or Japanese 'Metric' and German 'metric' as well ,,, ooops
All for the good old war machines of old ( and today ) , but we wont go there .
The good old USA will stay staunch on their beloved SAE , yes TPI's of most might be the same as UNF , but thread angles differ , sometimes but only 1 degree ( included ) so yes it will start but after 2 or 3 turns bind ,,, that's where a quality 'Thread Gauge' is essential , you have to be so careful here as a wrong bolt can get really expensive real fast ( especially in stainless steel that binds and friction welds and that's IT !!! no chance of un-doing ) .
How do I know about the German/Japan metric system being different ??? , owning both a Takahashi and Zeiss at the same time , both as good as ( engineering wise ) as the FT focusers and the tools will fit ,,, but >>> threads are the catch .
Thanks for your explanation Andrew by the way . There has been volumes printed on this subject but as I am only at 40 years of being a fitter /machinist/welder have seen this problem many a time as you seem to as well .
pss. , if it has this ,,, Made in the USA like this photo it will be SAE just like Asro physics , Feather Touch , and a few more , but NOT ! , like they say ' Designed in the USA ",,
,,,like many ( Japanese metric on a good day Chinglese metric made from plastic steel on a bad day ) ) , sorry to say sad but true .
Brian.
Quote:
Originally Posted by AndrewJ
If they are US made, they will more likely be UNC/UNF.
( IIRC, SAE is effectively replaced by UNF for "general purpose" bolts like this )
The English ( and us ) use mainly true Whitworth thread for these smaller dia general purpose bolts, and in that case, Whitworth and UNC are "effectively" interchangeable for dia/pitch, but have a different thread angles.
As such, the test board at Bunnings should be able to confirm the thread pitch and dia.
If they are true UNC, then as noted above, they may have a different thread angle to whitworth, and the numbering system for anything less than 1/4" also changes to a "gauge" based nomenclature.
Ref https://en.wikipedia.org/wiki/Unified_Thread_Standard
ie Below 1/4" the UNC bolt dia is defined by a gauge, not a fractional dia ( like you would see on a Bunnings Blister pack )
So for UNC fasteners, we get 1/4-20, then 12-24, then 10-24, then 8-32.
vs say 1/4, 3/16, 1/8 etc
The specialist suppliers do stock these true UNC sizes, whereas Bunnings etc dont.
( CostLess Bolts in Moorabbin has pretty much all of these sizes in SS, and is where i get most of mine from )
Andrew
Last edited by brian nordstrom; 26-05-2016 at 05:34 PM.
Reason: Photo added
Local Bunnies Whorehouse here is useless. Smallest capbolt they stock is M4. No imperial, nothing smaller than M4. Their range of general fasteners is attrocious, and I always end up buying my capbolts and screws from a local marine supplier (good quality stainless too) - last M3 cap bolts I got from them were $0.50 each.
1/2 BSW and 1/2 UNC are the only size under 1 inch that match
No they dont ( i suspect you missed a "dont" )
BSW is 12tpi, UNC is 13
That said, for all these sizes, the thread angle is always different,
and that can cause grief when mixed.
Quote:
There has been volumes printed on this subject
Thats the good thing about standards.
If you dont like the one you have, you can just choose another
Quote:
Made in the USA like this photo it will be SAE
Dunno.
More like "Assembled in the USA from local and imported ingredients"
SAE ( being closer to UNF ) means most US manufacturers wont use it.
They use UNC. I know this is true of all my Meades, my Lunt and my Feathertouch, as they all use UNC.
My homemade wedge adjusters use 1/2"UNEF,
but i havent seen that supplied in the US yet.
Andrew
PS My local bunnings do supply true "High Tensile" SAE bolts,
but only in the dedicated "Auto" section of the store, not the general fasteners area.
Oh my , lets not forget not forget good old metric , pitch , 1mm , 1,25mm 1.5mm and good old 1,75mm ,,,, .
Yes we can agree here that the standards in world wide threads are %$*! , but as I said its all to do with war , stops the enemy using your weapons against you . .
Doesn't really help us 'Joe Blogg's " here in amateur astronomy/ classic cars / / audio or any hobby that crosses the lines now does it ? .
Brian.
Quote:
Originally Posted by AndrewJ
Gday Brian
No they dont ( i suspect you missed a "dont" )
BSW is 12tpi, UNC is 13
That said, for all these sizes, the thread angle is always different,
and that can cause grief when mixed.
Thats the good thing about standards.
If you dont like the one you have, you can just choose another
Dunno.
More like "Assembled in the USA from local and imported ingredients"
SAE ( being closer to UNF ) means most US manufacturers wont use it.
They use UNC. I know this is true of all my Meades, my Lunt and my Feathertouch, as they all use UNC.
My homemade wedge adjusters use 1/2"UNEF,
but i havent seen that supplied in the US yet.
Andrew
PS My local bunnings do supply true "High Tensile" SAE bolts,
but only in the dedicated "Auto" section of the store, not the general fasteners area.
Local Bunnies Whorehouse here is useless. Smallest capbolt they stock is M4. No imperial, nothing smaller than M4. Their range of general fasteners is attrocious, and I always end up buying my capbolts and screws from a local marine supplier (good quality stainless too) - last M3 cap bolts I got from them were $0.50 each.
Doesn't really help us 'Joe Blogg's " here in amateur astronomy/ classic cars / / audio or any hobby that crosses the lines now does it ?
Nup, but as i noted, most US "astro" gear is UNC,
so its easy enough to get.
Its also why i have a box full of different taps and dies ,
and also reverse engineered the thread cutting gears on my lathe
so i can cut just about anything i want.
The mainly annoying bit is swapping 55 and 60deg inserts based on thread wanted.
Agreed , the 55/60/27 inclusive are a major trap for most people , even suppliers struggle with this .
Need a good thread gauge and Vernier caliper are a must .
On the USA only SAE thread's , yes you are right but I would say pre 1990 all USA gear was using SAE , only now the 'Designed" and like our food here in OZ , made from local and imported ...........
Ingrediants .....
A world I find obscene .
Full of lies .
Brian.
Quote:
Originally Posted by AndrewJ
Gday Brian
Nup, but as i noted, most US "astro" gear is UNC,
so its easy enough to get.
Its also why i have a box full of different taps and dies ,
and also reverse engineered the thread cutting gears on my lathe
so i can cut just about anything i want.
The mainly annoying bit is swapping 55 and 60deg inserts based on thread wanted.
My first stop in Oakleigh would be Tony's Hardware on Chester St. If he doesn't have what you're after he should be able to tell you what you need: measure thread pitch etc, give you the specs so you can look for it online. I've always found him extremely helpful. It's a classic little local family run hardware shop hanging in there despite the likes of Bunnings. As I recall in the 2000s it was also a bit of a local social community hub, especially on Saturdays.
Tony's English is not brilliant but he usually has fluent help on hand. I moved out of the area a while back and last visited 5+ years ago so I'm assuming he hasn't sold it in the meantime; or his sons/daughters might have taken over. In any case it's worth a shot.
My first stop in Oakleigh would be Tony's Hardware on Chester St. If he doesn't have what you're after he should be able to tell you what you need: measure thread pitch etc, give you the specs so you can look for it online. I've always found him extremely helpful.
Thanks for the tip. I walk past that store all the time but I've never been in. Will check it out.
I've always used a company United Fasteners for specialized threads etc. Most fastener stores will carry a fairly comprehensive range for this type of stuff.
I believe United have a Melbourne presence as well.
No don't go to Bunnings , they will not have the correct screws in stock because being USA made they will be an SAE thread in imperial size ( different again to the English UNC/UNF threads , but the same diameters ) , Bunnings don't stock SAE and the person you deal with will probably look at you like you are from another PLANET .. .
forced a close metric bolt in , has it damaged the focuser threads ? .
' .
'
Yes they have , but the confusion is still there , I left out 'BSW' for this reason ( 1/2 BSW and 1/2 UNC are the only size under 1 inch that match , the rest have a different included pitch angle ) , or Japanese 'Metric' and German 'metric' as well ,,, ooops 
.
, owning both a Takahashi and Zeiss at the same time , both as good as ( engineering wise ) as the FT focusers and the tools will fit ,,, but >>> threads 
.
