Jump to content


Photo

T-Rex homemade motor solution

  • Please log in to reply
11 replies to this topic

#1 Lane

Lane

    Soyuz

  • -----
  • Posts: 3593
  • Joined: 19 Nov 2007
  • Loc: Frisco, Texas

Posted 06 November 2013 - 01:16 AM

I got a message from someone wanting some help putting motors on a T-Rex so I thought I would re-post some pictures here that I posted in the past. These show the custom brackets I made to attach JMI motors to my T-Rex mount. It is really a very simple solution that anyone can do. I have used this solution for several months now and it is still working perfect, I never even remove the motors anymore, I just keep them attached to the mount and it all fits perfectly in the carrying case.

The motors I bought came with up/down left/right type hand controllers, but they are the same motors supplied with the JMI Train-n-Track system, which came out after I bought my system. What I bought was made to fit the AstroTech Voyager mount. I ditched the brackets and made my own. My brackets attach to the motor with only one bolt and to the mount with only one bolt. The only problem I ran into was getting the right coupler to attach the motor to the T-Rex shaft. The shaft on the AstroTech is different, so I bought two couplers from JMI for $12.00. The T-Rex comes with a coupler adapter for each of the flexible handles. I used those adapters in my solution which meant that the motor and the T-Rex shaft sizes were then identical. So the couplers I got from JMI are just simple straight through couplers and readily available from JMI.

#2 Lane

Lane

    Soyuz

  • -----
  • Posts: 3593
  • Joined: 19 Nov 2007
  • Loc: Frisco, Texas

Posted 06 November 2013 - 01:19 AM

Pic 1

Attached Files



#3 Lane

Lane

    Soyuz

  • -----
  • Posts: 3593
  • Joined: 19 Nov 2007
  • Loc: Frisco, Texas

Posted 06 November 2013 - 01:21 AM

Pic 2 - I replaced the bolt on the mount with one that is about 1/8" longer. That allowed me to put 2 washers on the bolt and attach my mount between them. This was to keep from scratching the T-Rex when attaching and removing my bracket.

Attached Files



#4 Lane

Lane

    Soyuz

  • -----
  • Posts: 3593
  • Joined: 19 Nov 2007
  • Loc: Frisco, Texas

Posted 06 November 2013 - 01:21 AM

Pic 3 - the couplers are those little silver cylinders with the two set screws in them. Not cheap ($12 for the pair as I recall from JMI). The shaft on that motor is the same size as the shaft on the adapter that comes with the T-Rex.

Attached Files



#5 Lane

Lane

    Soyuz

  • -----
  • Posts: 3593
  • Joined: 19 Nov 2007
  • Loc: Frisco, Texas

Posted 06 November 2013 - 01:22 AM

Pic 4

Attached Files



#6 Lane

Lane

    Soyuz

  • -----
  • Posts: 3593
  • Joined: 19 Nov 2007
  • Loc: Frisco, Texas

Posted 06 November 2013 - 01:23 AM

Pic 5

Attached Files



#7 Lane

Lane

    Soyuz

  • -----
  • Posts: 3593
  • Joined: 19 Nov 2007
  • Loc: Frisco, Texas

Posted 06 November 2013 - 01:24 AM

Pic 6

Attached Files



#8 Lane

Lane

    Soyuz

  • -----
  • Posts: 3593
  • Joined: 19 Nov 2007
  • Loc: Frisco, Texas

Posted 06 November 2013 - 01:26 AM

Pic 7 - I don't think they degrade the mount's appearance at all and they do not get in the way of the mechanical operation of the mount in anyway.

Attached Files



#9 Lane

Lane

    Soyuz

  • -----
  • Posts: 3593
  • Joined: 19 Nov 2007
  • Loc: Frisco, Texas

Posted 06 November 2013 - 01:39 AM

The Train-n-Track is probably a lot nicer than the simple controller I own. If anyone does attach one of those to this mount I would be interested in hearing about its performance. The thing I never liked about the controllers I own is that they always start slowly and then speed up after you hold down the button for about a second. That delay does not sound like much but it can be very annoying after a while.

#10 beatlejuice

beatlejuice

    Surveyor 1

  • *****
  • Posts: 1667
  • Joined: 05 Apr 2011
  • Loc: Hamilton, ON,Canada

Posted 06 November 2013 - 03:43 PM

The thing I never liked about the controllers I own is that they always start slowly and then speed up after you hold down the button for about a second.



This is the same with the TNT controller when using what they call the high speed buttons. But the TNT also has 2 levers for adjusting tracking speed or centering an object. These levers provide very smooth motion within the FOV that you are currently viewing.
I imagine this would be the same for whatever mount it was used for.

Eric

#11 Joe H

Joe H

    Vostok 1

  • *****
  • Posts: 122
  • Joined: 19 Jul 2006

Posted 08 November 2013 - 06:07 PM

Just a note it is possible to purchase the 1/4" X 3/8" shaft couplers on ebay. Just put in 1/4 3/8 shaft coupler and you will get some choices. These are not super cheap either. The mounting bracket with Train n Track seem like they will work by slipping under the screws that hold on the slo motion cover. I'll get a chance to test this soon.
Joe

#12 EFT

EFT

    Vendor - Deep Space Products

  • *****
  • Vendors
  • Posts: 2567
  • Joined: 07 May 2007
  • Loc: Phoenix, AZ

Posted 08 November 2013 - 07:30 PM

Just a note it is possible to purchase the 1/4" X 3/8" shaft couplers on ebay. Just put in 1/4 3/8 shaft coupler and you will get some choices. These are not super cheap either. The mounting bracket with Train n Track seem like they will work by slipping under the screws that hold on the slo motion cover. I'll get a chance to test this soon.
Joe


Keep in mind that the worm shafts are 10mm, so you will need to bore out the coupling by about 0.525mm in order for a 3/8" coupling to fit. Metric couplings are much harder to find.






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics