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Takahashi MT-160 Dobsonian build

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#1 Tyson M

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Posted 14 March 2019 - 09:35 PM

Hello all,

 

I got the Takahashi MT-160 as the ultimate grab and go set up. A 6" dob is hardly taxing to move around or set up.

 

I got this idea for this project because of the funky positioning that a newtonian has for the viewing angle on an EQ mount.  On an Alt az mount, a newtonian sits up high and you cannot sit down, because you typically need a mount extension to clear the legs.  At least this was the case with me and trying to mount it on my heavy duty alt az mount.

 

I figured the best thing I could do for a scope like this was to get a custom made dob mount built for it.  It would be a small dob that packs a punch and would be easy to lug out at a moments notice from my garage.

 

Going on a recommendation of a fellow CN member TheArdent, I reached out to Dennis at Dobstuff for the hardest part- the cuts.

 

I don't have the proper tools nor do I have a lot of time, as I am going to post secondary.

 

I did figure I was handy enough to do the sanding, stain, varnish and assembling.

 

I placed my order with Dennis from Dobstuff and it was completed fairly fast. One thing I really like about Dennis is how fast he communicates with you before and after the sale.  This price was reasonable as well.

 

I got a pack of all the necessary supplies and the pencil traces of where the parts go, relative to each other.

 

I did not get any assembling instructions, but it was not needed since Dennis was able to answer and questions I had. This was my first time staining and varnishing a wood piece.

 

Pictures and brief write up on the steps to follow.

 

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#2 Tyson M

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Posted 14 March 2019 - 09:36 PM

Here are a few more pics of the initial materials and traced lines.

 

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#3 Tyson M

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Posted 14 March 2019 - 10:18 PM

The next working day on this project, I spent a couple hours sanding each side of each piece, and the edges round, with 220 grit sand paper.

 

Dennis did most of the sanding and my project didnt absolutely need it, but I wanted it to look nice and protect the edges by rounding them out a bit. 

 

If not, any bump could rip a piece off.


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#4 Tyson M

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Posted 14 March 2019 - 10:30 PM

Today I spent all day staining and varnishing.  To use the stain, you first apply, then 3 minutes later wipe with a cloth/rag (I used paper towel because that is all I had).  After that, let it set for an hour. I repeated this process for the back side of each piece so this was approx a 3 hour job.

 

Next, you varnish it. This said after applying it, to wait 6 hours to cure. I didnt have 6 hours and wanted to do both sides and I got impatient, which I should not have done. After an hour, I applied a coat on the back side.  To make matters worse, I was in a hurry and got excess varnish on the back side of the pieces I had propped up.  Also, varnish went through the predrilled holes to the back side of my main circle base.

 

I came back out after 3.5 hours and released my mistake. Lesson learned. By rushing it, I caused myself more work in the process and delayed the completion of the build by an entire working day.

 

I sanded the runs and blobs back down with 220 grit paper and reapplied the stain. Waited 3 minutes to wipe access, then another hour to dry. 

 

I finished off the night today by varnishing the 3 sides of the pieces that were mucked up. 

 

The good news, 2 pieces were repaired successfully.  One side of the rockerbox was not repaired as well as I would have liked from the runs. It is not a big deal, it is facing the inside of the rocker box and really this base is meant to be used, not an art piece.

 

Here is my progress up until now. I hope to finish assembling it this weekend and will update this thread.

 

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Edited by Tyson M, 14 March 2019 - 10:31 PM.

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#5 Tyson M

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Posted 17 March 2019 - 07:25 PM

Progress on my front.  Assembling the rocker box. Glued laminate to alt bearings with contact cement and held in place with clamps overnight.

 

Had some challenges again.  I somehow split one of my side supports while drilling into it. Not once, but twice! Once on the top and once on the base. 

 

I tried gluing it, but it is split bad.  Dennis from Dobstuff is kind enough to make another send me another triangle support (I will pay shipping).

 

I also comically assembled the whole thing, and realized I had the back piece with its rougher looking side facing outwards! Doh!  I had to back out the 6 screws that were wood glued and flip it around and put it back in. This time not gluing each one again.  Only the odd one was re-glued.

 

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#6 Tyson M

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Posted 17 March 2019 - 07:39 PM

I would have finished the dob build today, but I had some issues with the alt bearings. I panicked when I put them with tube rings on the completed rockerbox and az bearing just to find out I was out by a half inch or so, way too big.

 

No way Dennis made that error I thought, this isnt his first rodeo.  I took great care squaring it up using his provided spacer, but I had 1/8" flaring outwards from perpendicular on the front of one side, shouldnt have made that a deal breaker.

 

I emailed Dennis for his thoughts on how to attack this problem without destroying the mount as I glued the large laminate already on the bottom of the rockerbox, covered the recessed bottom screws.  I let it dry overnight with clamps and contact cement and REALLY didnt want to destroy that because of error in piece sizes.

 

I let out a huge sigh of relief when he told me I assembled the alt bearings to the tube rings of my Tak newt backwards!

 

Once Dennis advised me the lip of the alt bearings goes on the INSIDE not outside, everything fit perfectly like it should.  

 

I had to do some further staining and varnishing to touch up the alt bearings as what I thought were the inside surfaces are now actually the outside pieces.

 

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Edited by Tyson M, 17 March 2019 - 07:40 PM.

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#7 Tyson M

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Posted 18 March 2019 - 05:47 PM

It is finished!  All in all I have to say is I am impressed and proud to have done this.  It looks exactly how I wanted it and it functionality wise, works great!

 

It taught my a lesson on patience as well, and that a dob is never truly finished, as you always end up tinkering around to optimize it more. I will repair one of the triangle supports once I receive it to one that is not split on the ends.

 

This project would not have been possible, nor so nice looking without Dennis from Dobstuff's help throughout my entire journey.

 

From his nice measurements and cuts, to sending all the required supplies, and ongoing help and recommendations, I cannot express my gratitude more! 

 

Anyone thinking about a wood project for a custom dob base, look no further and give him an email.

 

Thanks for reading this far and clear skies!

 

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Edited by Tyson M, 18 March 2019 - 08:34 PM.

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#8 Tyson M

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Posted 18 March 2019 - 05:48 PM

Here it is from the other side.

 

20190318_161050.jpg


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#9 Tyson M

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Posted 18 March 2019 - 05:50 PM

20190318_161001.jpg


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#10 havasman

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Posted 18 March 2019 - 07:05 PM

That's going to be a lot of fun to use. Very nice job!


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#11 Kunama

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Posted 18 March 2019 - 07:30 PM

Great result Tyson, from all reports the MT160 is a fine scope and in this configuration it will make a fantastic Grab&Go if you don't store it in a heated house.... 


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#12 Tyson M

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Posted 18 March 2019 - 07:47 PM

Great result Tyson, from all reports the MT160 is a fine scope and in this configuration it will make a fantastic Grab&Go if you don't store it in a heated house.... 

It will  be stored in the garage in a soft case ready to go :)



#13 The Ardent

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Posted 18 March 2019 - 08:44 PM

That’s pretty awesome! 



#14 NHRob

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Posted 19 March 2019 - 05:50 PM

How are the optics?



#15 siriusandthepup

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Posted 19 March 2019 - 10:53 PM

This will be your all time favorite scope. Guaranteed. waytogo.gif



#16 Tyson M

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Posted 20 March 2019 - 09:08 PM

How are the optics?

Optics are very good. I enjoyed the near full moon with decent seeing and transparency last night and its corrector. 

 

Could handle a 4mm Delite @ 1330mm focal length, but I backed it down to 8-10 Delos for visually appealing views in the conditions. The lumicon number 21 orange filter really brought out the contrast and all my eyepieces benefited. 

 

Without the corrector, I put in a 40XL and saw beautiful diffraction spikes on brighter stars but stars had coma showing as expected for this low power and with this eyepiece.

 

Stars very good, not quite apo like but similar to a MN66 I had (minus the diffraction spikes).




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