drilling new holes in my scope

[Daniel-K]

hi i need to make the existing hole were my focuser sits in wider is there an easy way i have treid the other day with a hole saw(bi metal) but just scrated the paint its 82mm at the moment and needs to be 95mm for the new focuser to sit nicely in

thanks

danny

[johninderby]

The easiest way is just to drill a series of small holes around the circumference of the new size hole and then connect all the little holes with a mini hacksaw blade.

Here's the link showing how it works. Tedious work but it only takes about 15 minutes.

http://stargazerslounge.com/diy-astronomer/119323-fitting-2-focuser-skywatcher-150pl-newt-ota.html

John

[Daniel-K]

wooo thanks john give me some thing to do today

[Ad Astra]

Just remember the old carpenter's adage:

Measure twice, cut once!

Dan

[barkis]

Either remove the secondary, or cover it carefully, the main mirror too, before doing anything. Those filing dust and swarf can be invasive.

Ron.

[Kevdan]

Just a note, get some masking tape, cover the hole with masking tape and mark out the new one, As has been already said take out or cover your mirrors, You could use something like a dremmel to cut the new hole which will be a cleaner finish but it will take time, Just remember this only has to be done once and done right.

Hope this helps.

Kev.

[Ad Astra]

Absolutely agree with removing all the glass before you drill into the OTA. Flying metal fragments can cause a lot of damage!

Sadly, I had to learn this the hard way on an old scope I was trying to refurbish years ago... it ended up in the rubish heap.

[focaldepth]

Another trick is to get a volunteer to hold a vacuum near to the drilling/filing. Although their arms get tired before yours do.

[boston]

Hi

Have you tried any engineers supplies, I can recall some years ago being able to hire a hole cutter (at differing sizes) to cut through sheet metal without the need of having to drill, grind or saw.

These were like a socket wrench which simply cut the hole to the required size whilst tightening against a backing disc of the same size.

[Peter Drew]

A hole cutter only really works from scratch when there is something for the pilot drill to centre on, enlarging an existing hole, particularly on a curved surface is an accident waiting to happen:eek:. Frankly, I would open up the pre marked off hole with a suitable round or half round file after taking the precautions already posted.

[glowjet]

I would agree with Peter, steer clear of any hole cutter, a small half round file and patience, finish off with a small drum sander in an electric drill, then throughly clean.

[Daniel-K]

i bought a dremel 200 series from B&Q for £35 its a starter pack came with cuttin disk sander and a few other bits has work brilliant would recomend it to any one looking to this with this tool it is a nightmere!