Recently acquired a TOA15 with the 4 inch focuser. Also purchased a Tak MEF-4 fine focuser upgrade.
The MEF-4 looks and feels very well built but I need a bit of quick advice on the fitment as I dont want to screw up my new TOA150 focuser housing and all the instructions are in Japanese LoL
The connection of MEF-4 to the focuser shaft looks very simple and straight forward. Essentially remove old knob and put on new knob and tighten down a couple of tension bolts.
The problem is the plate that connect to the bottom of the focuser housing and to the MEF-4. There is no second screw hole on the bottom of my housing. Only one. So it looks like I would have to drill into the outer casing.
However the supplied screw does not look like a self tapping type screw.
So anyone that has fitted one before I would be grateful for the advice.
The supplied screw can be used in place of the flat nut that normally holds the cover over the focuser - at least that's how it works on my TSA120.
Hi Tony,
Thanks for the suggestion. Thats what I first thought but the external housing on the TOA150 4 inch focuser is quiet large and the focus shaft is offset significantly to where that screw is located. However there are no other screw holes anywhere else on the casing so it looks like some drill work which is ok as I have very good drill but I wanted to make 100% sure before I do something which cannot be undone !
The english text on the web site says it installs in minutes so I assummed that it would have come with a new housing or different nut and bolt rather than the small phillips head screw that looks like it is suited for a pre-drilled and properly threaded hole.
So basically I wanted to make sure I wasn't missing anything so looks like I will have to get a better bolt and nut then drill it myself.
The one on my FCT is a threaded hole, so no nut required at all.
I have 2 MEF-3's, so just made a new angled bracket for it, plus I ordered a genuine MEF-4 bracket through Claude also (but still wrong colour, seeing mine is grey, not green - perhaps the new MEF brackets are stainless again and NOT painted.
The focuser mechanism is on the other side, and on these, it's quite a technical masterpiece - not sure if they continued it, but the FCT's have a tensioner plate (chromed) on TOP of the pinion casting to make sure the pressure is equal. I know the FSQ-106N does NOT have it, so perhaps the newer versions don't.
I will definitely take the housing of to drill it :-)
I have not drilled a cast housing like this before and had heard that some cast housing have a tendency to crack and was wondering if that is a potential problem.
The focuser mechanism underneath on the my TOA150 looks like a very solid metallic box or plate that curves around to surround the entire inner focusing mechanism. But it has not been chromed.
New bit, go slow, use cutting oil. Shouldn't be an issue
I would still personally thread the hole, but entirely up to you. If you use a nut. once positioned, I would use loctite on the nut. There is quite a bit of torsional force on these.
Tak could learn something from this. I would have been happy to fork out an extra $50 or so if they supplied a pre-drilled replacement housing with a better nut and bolt as part of the kit.
Im happy to customise and do a bit of handy work myself but for a scope like the TOA150 a very useful accessory like the MEF4 should just be a screwdriver job
Honestly for the price of a TOA150 the MEF-4 should be standard equipment issue or at least provision for the upgrade. It's bs that you have to resort to drilling to accommodate a genuine accessory.....good luck with the fit out.
Just thought I would post these details for the MEF-4 fit-out for Takahashi TOA150.
The MEF-4 is the Fine Focus adaptor for the TOA150 with the large 4 inch focuser.
The MEF-4 arrives in a small rectangular box and all the items are very well packed in air-bubble wrap.
It ships with all the included items as per the attached picture which is:
MEF-4, torsion bracket, 2 x grub screws to fix the MEF-4 to the focuser shaft, 2 screws to fix the torsion bracket to the MEF-4, 1 screw to fix the torsion bracket to the external focuser housing and one allen key to tighten/loosen the grub screws.
Unfortunately the supplied instruction sheet is only in Japanese with no english instructions at all.
First step is to remove one of the old focuser knobs.
You can remove either side focuser knob as the MEF-4 is really just a fully self contained 1:7 reduction gear. For me I am right handed so I removed the right hand focuser knob (standing behind the scope).
The old focuser knob is removed with a phillips screwdriver.
Remove the outer focuser housing which is just held in place by a single phillips head screw/bolt.
Put the 2 supplied grub screws into the 2 holes in the MEF-4 using the supplied allen key.
Then push the MEF-4 onto the focuser shaft until it can't go any further.
Tighten down both grub screws so the MEF-4 is secured well to the shaft.
The images in the supplied instructions suggest to drill a hole into the external focuser casing and actual show spacing measurements for placement of the hole. When I compare this to my focuser housing and the supplied torsion bracket the suggested position looks out by several millimetres.
Also the pictures in the supplied instructions imply that the screw that attaches the torsion plate to the external focuser housing is just secured by screwing it into the housing itself.
So normally the final steps would be to drill the hole into the focuser housing, place the focuser housing back on the scope and tighten down with the original single screw, then secure the torsion plate to the MEF-4 and lastly secure the other end of the torsion plate to the external focuser housing by swearing it down into the newly drilled hole with the new screw supplied with the MEF-4.
However, I have decided to replace that screw with a bolt and nut ( a M4 12mm chrome with a head similar to all the other tak heads). So the procedure will change to:
Secure the torsion plate to the external focuser casing with the nut on the inside of the casing and making sure that the torsion plate is positioned and oriented correctly.
Replace the external focuser casing on the scope and secure with the original screw.
Secure the other end of the torsion plate to the MEF-4.
That should complete the fit out :-)
PS
For those interested in purchasing I just wanted to say that the cost including delivery from Claude at AEC was cheaper than any alternative supplier I could find on the internet.
I see Tak did drop the tensioner plate entirely from later production. Will photograph mine later. THey also polished and painted the pinion cradle casting on mine too. Yours and the FSQ-106N of Humayun have a non-painted semi-finished look. Cost cutting where not necessary detailing was concerned.
As you can see I have used a Cap Bolt similar to all the other Takahashi Cap Bolt Styles. Instead of using the supplied 6mm phillips screw
In this case it is a M4 12mm Cap Bolt.
Also as you can see the Cap Bolt is very slightly offset from the original phillips head bolt that secures the focuser housing. This is due to the torsion bar being slightly longer than what I think Tak originally specified.
It secured by the cap bolt with a nut underneath the housing at one end and 2 phillips head screws at the other end.
Hope this helps someone in the future as I could not find any articles or english speaking documents on the MEF-4 itself or MEF-4 fit-out anywhere on the web myself.
Ahh maybe thats it. There is absolutely no mention of how to position it in the Japanese instruction sheet . I just snugged it up to look close to how things were positioned before. Seems to be fine as it is but will tell when I take it out for a full nights use.