Jump to content


Photo

Drilling holes in XT8 Dob

  • Please log in to reply
48 replies to this topic

#1 Allan...

Allan...

    Ranger 4

  • -----
  • Posts: 346
  • Joined: 24 Oct 2012
  • Loc: Penticton B.C. Canada

Posted 12 January 2013 - 09:42 PM

I was wondering how best to (if I dare) drill a hole in my XT8 OTA....would like to put on one of those rubber navigation knobs on the top end (like the ones that come with the Intelliscopes and even on the XT4.5). Not sure why they left them off the classic models. I find that grabbing the tube isn't the best method. Think the knob would simplify things. I have visions of starting the drill bit and having it SLIP and oops....one nasty scratch on the OTA. One cant really expect to use a centre punch to start the hole. Anyone got any fool proof methods up their sleeve? thanks, Clare :)

#2 CosmoSat

CosmoSat

    Apollo

  • -----
  • Posts: 1272
  • Joined: 24 Jul 2009
  • Loc: India

Posted 12 January 2013 - 09:56 PM

Remove the optics along with their cells and holders and then do the drilling, one of these days u will hve to do that to clean them anyway.

Clear Skies!

#3 newtoskies

newtoskies

    Apollo

  • -----
  • Posts: 1441
  • Joined: 15 Jul 2012
  • Loc: SE Ma.

Posted 12 January 2013 - 09:59 PM

Try using a piece of tape and a smaller drill bit first. Drill the pilot hole slow and the tape should keep the bit from sliding. Then use the appropriate bit you need for the screw.I use this trick for drilling in ceramic tile and it work all the time.

#4 dpwoos

dpwoos

    Apollo

  • *****
  • Posts: 1355
  • Joined: 18 Oct 2006
  • Loc: United States

Posted 12 January 2013 - 09:59 PM

Center punch as much as you want - what's the big deal?

#5 newtoskies

newtoskies

    Apollo

  • -----
  • Posts: 1441
  • Joined: 15 Jul 2012
  • Loc: SE Ma.

Posted 12 January 2013 - 10:00 PM

Forgot...keep the OTA horizontal and place a towel in the tube to catch debris.

#6 JamesL

JamesL

    Explorer 1

  • -----
  • Posts: 95
  • Joined: 19 Oct 2012
  • Loc: Pacific,MO

Posted 12 January 2013 - 10:19 PM

Possibly you could lay down a piece of 2"blue painters tape from a new roll that is not too sticky over the area to be drilled. Then use a "sharp" center punch and with the palm of your hand (instead of a hammer) apply enough pressure to create a small recess for the "sharp" drill bit to ride in.
Hold drill as purpendicular as possible and when it plunges through hopfully nothing is on the other side. Some metal shards will fall inside, make sure they fall away from any optical surfaces of course.Then slowly remove the tape as to not pull any paint off. Then vaccume it out. This is just an idea of mine, maybe someone else that has done it will chime in. Please excuse my spelling...James

#7 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 43349
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 12 January 2013 - 11:24 PM

It's a little scary drilling holes in a beautiful black steel tube but it is doable without much trouble. As others have said, use a center punch, start with a smaller drill. Make sure that there is something inside to catch any shards, I often put some grease where the drill will break through. Take it slow and easy, use a sharp drill and all will be well.

Jon

#8 JLovell

JLovell

    Viking 1

  • -----
  • Posts: 850
  • Joined: 12 Jan 2010
  • Loc: Georgia

Posted 13 January 2013 - 07:10 AM

If you are afraid of removing the optics, stand the scope vertically with the mirror end up, and have someone hold it so it won't fall over. You can put it on a chair or table to give you some room off the floor for the drill. Another possibility to help catch shavings is to put a strong magnet on the inside near, but not in the way of, the spot the drill will break through. The magnet will catch any shards that came loose on the inside. The vast majority will be outside the tube.

Another thing to try, if you have vice grips or a similar clamp, is clamping a small nut or washer with a small hole to the rim of the scope to keep the bit from wandering too much. Drill through the hole. A piece of blue tape underneath will prevent any scratches from the washer/nut and the vice grips. If you use a nut, use one you don't need, as you'll likely damage the threads.

#9 CosmoSat

CosmoSat

    Apollo

  • -----
  • Posts: 1272
  • Joined: 24 Jul 2009
  • Loc: India

Posted 13 January 2013 - 10:19 AM

I find that grabbing the tube isn't the best method.


But why do u think grabbing the tube isn't the best method? I think otherwise...that grabbing the tube gives more control when nudging at high powers.. In fact while moving the telescope I habitually hold both ends of the tube to have maximum control on the motion.


Clear Skies!

#10 NeilMac

NeilMac

    Gemini

  • -----
  • Posts: 3062
  • Joined: 25 Sep 2010
  • Loc: MedHat, AB, Canada

Posted 13 January 2013 - 10:23 AM

grabbing the tube is what I do, I find it awkward to grab the knob.

#11 Jim Nelson

Jim Nelson

    Viking 1

  • -----
  • Posts: 925
  • Joined: 10 May 2005
  • Loc: SE Michigan

Posted 13 January 2013 - 10:34 AM

When I had the knob, I rarely used it. I just grabbed the tube.

If you haven't had personal experience with the knob, I wouldn't go through the effort of installing one and drilling a hole to do so.

(Conversely, ff you have and know you want one, by all means go to it!)

#12 Atl

Atl

    Viking 1

  • *****
  • Posts: 501
  • Joined: 13 Apr 2012

Posted 13 January 2013 - 10:40 AM

I grab the tube...a knob seems like an unnecessary extra...just more weight.

#13 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 43349
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 13 January 2013 - 10:41 AM

I find that grabbing the tube isn't the best method.


But why do u think grabbing the tube isn't the best method? I think otherwise...that grabbing the tube gives more control when nudging at high powers.. In fact while moving the telescope I habitually hold both ends of the tube to have maximum control on the motion.


Clear Skies!


One problem with grabbing the tube is that just touching the metal tube with your warm hand is likely to cause tube currents that disrupt the image. These are not big tube currents but at higher magnifications they are sufficient to affect the view for a minuter or more.

If I am going after the best possible views with a metal tubed dob, I wear gloves even if it is not cold to insulate my hand from the scope...

If I am using two hands as is sometimes necessary to track near the zenith, one hand is on the tube for the altitude motion, the other is on the base to rotate the azimuth. The base provides more leverage, finer control and does not have the possibility of creating tube currents.

As far as drilling holes. I do with the tube horizontal so the filling, or anything for that matter, cannot fall into the optics. Laying the tube on a couch provides solid backing.

Jon

#14 Atl

Atl

    Viking 1

  • *****
  • Posts: 501
  • Joined: 13 Apr 2012

Posted 13 January 2013 - 10:42 AM

True. My tube is sonotube...but Orion uses metal.

#15 drewp

drewp

    Viking 1

  • *****
  • Posts: 559
  • Joined: 19 May 2007
  • Loc: 41.5 deg north moline ill

Posted 13 January 2013 - 12:29 PM

i have never heard of heat from the hand having any effect on tube currents. turn on your fan and forget the knob.

#16 Haas

Haas

    Ranger 4

  • -----
  • Posts: 321
  • Joined: 22 Nov 2012
  • Loc: Wis., USA

Posted 13 January 2013 - 12:48 PM

Couldn't center punching, create a rather large indent on the tube? I know you want a dimple for the drill to "find", but it seems there's a risk that a large portion of the tube could dent inwards from the impact.

#17 planet earth

planet earth

    Surveyor 1

  • ****-
  • Posts: 1613
  • Joined: 07 Sep 2010
  • Loc: Ontario Canada

Posted 13 January 2013 - 12:54 PM

a knob seems like an unnecessary extra...just more weight.


Well if you use an old brass door knob and hang your coat on it, what do you expect? :lol:
Sam

#18 howard929

howard929

    Member

  • *****
  • Posts: 3415
  • Joined: 02 Jan 2011
  • Loc: Low End of High Ground

Posted 13 January 2013 - 12:54 PM

A Strap-A-Handle or two would be an ok work around to drilling as well as a way to carry the OTA.

#19 StarCurious

StarCurious

    Sputnik

  • -----
  • Posts: 40
  • Joined: 24 Dec 2012
  • Loc: York Region, Ontario

Posted 13 January 2013 - 01:42 PM

Try Google suction cup handle, and found something like this:

http://www.amazon.co...0EM8/ref=pd_...

Don't know if it would be too strong and distort your OTA.

#20 jimdp

jimdp

    Lift Off

  • -----
  • Posts: 9
  • Joined: 17 Jun 2012
  • Loc: Vista, CA

Posted 13 January 2013 - 01:59 PM

J b weld with a wooden knob...now were talking custom..

#21 kfiscus

kfiscus

    Vanguard

  • *****
  • Posts: 2106
  • Joined: 09 Jul 2012
  • Loc: Albert Lea, MN, USA

Posted 13 January 2013 - 03:05 PM

PM sent.

#22 Allan...

Allan...

    Ranger 4

  • -----
  • Posts: 346
  • Joined: 24 Oct 2012
  • Loc: Penticton B.C. Canada

Posted 13 January 2013 - 04:31 PM

Got er!

#23 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 43349
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 13 January 2013 - 07:04 PM

i have never heard of heat from the hand having any effect on tube currents. turn on your fan and forget the knob.


A tube current caused by your body heat is not something you hear, it is something that you can see through the eyepiece.

To see the effect of your body heat, you need to start with a thermally stable scope. Point the scope at bright star using a moderate magnification (200x) and defocus the image, place your hand in front of the scope and you can see the heat rising. If the seeing is sufficiently stable you can see the effect of just touching the tube with your warm hand.

I have owned my trusted 10 inch F/5 Made in Taiwan GSO Dob for about 10 years. On an excellent night, it is capable of resolving double stars at the Dawes Limit.. 0.5 arc-seconds, about one fifth the separation of the double-double. Using gloves is one trick I learned that makes this possible.

Jon

#24 kenrenard

kenrenard

    Surveyor 1

  • -----
  • Posts: 1562
  • Joined: 13 Dec 2012
  • Loc: Dunmore, PA

Posted 13 January 2013 - 07:12 PM

i have never heard of heat from the hand having any effect on tube currents. turn on your fan and forget the knob.


A tube current caused by your body heat is not something you hear, it is something that you can see through the eyepiece.

To see the effect of your body heat, you need to start with a thermally stable scope. Point the scope at bright star using a moderate magnification (200x) and defocus the image, place your hand in front of the scope and you can see the heat rising. If the seeing is sufficiently stable you can see the effect of just touching the tube with your warm hand.

I have owned my trusted 10 inch F/5 Made in Taiwan GSO Dob for about 10 years. On an excellent night, it is capable of resolving double stars at the Dawes Limit.. 0.5 arc-seconds, about one fifth the separation of the double-double. Using gloves is one trick I learned that makes this possible.

Jon



That's interesting. Jon you are full of wisdom. I wouldn't even think of that. I thought I was clever using small magnets as counterweights and using a towel over my head to block out stray light.

It would be interesting to find some more tricks that experienced observers use. Sky and Telescope just this month had an observing article with using an eyepatch to dark adapt. I was thinking about it but my kids might think I am a pirate.

Ken

#25 skinnyonce

skinnyonce

    Vostok 1

  • *****
  • Posts: 197
  • Joined: 23 Mar 2011
  • Loc: ohio

Posted 13 January 2013 - 07:26 PM

i have never heard of heat from the hand having any effect on tube currents. turn on your fan and forget the knob.


A tube current caused by your body heat is not something you hear, it is something that you can see through the eye front of the scope and you can see the heat rising. just touching the tube with your warm hand.
Jon


Just wear a glove then






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics