Tabletop Alt-Az mount concept - incomplete project

Wanna make a scope? Or better still, grind a mirror yourself. Or, you have some good tips in making a really useful accessory? This is the place to show what your hands can do...
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Joined: Fri May 17, 2013 2:50 am
Favourite scope: maksutov

Tabletop Alt-Az mount concept - incomplete project

Post by Hardwarezone »

Post here to share my experience as recently these few weeks there were forumers looking to mount C90 mak and 5inch newt OTA.
IMO if can bring down the cost of mount , the lower entry barrier will allow more to join this hobby.
Maybe somebody can finish the idea and build something similar.

This wooden tabletop mount was built around 2017 for my 50mm finderscope for quick view when I lazy to setup the tripod and mount.
Inspired when i looked at 4" 6" diskmount images from 2013-2014.
Built it way oversized but did not solve the problem on how to create a saddle for vixen dovetail dimensions. That 75 degree angle cut.
Even when I gave in and bought a ready-made saddle clamp , I don't have solution to mount it as the steel bolt head protrude and interfere.
I anticipate to avoid the shaft bolt head and have bolt-nut attachment for the saddle , the wood disk will need 1-2 more layer and many big holes.
Lazy shortcut alternative is using steel L bracket and make the saddle hold the telescope from under. The L bracket may introduce vibration.

Holding 50mm RACI finderscope without issue.

I'm stuck here with no solution , haha
Protruding shaft bolt head and need to attach the saddle clamp ontop.
The wooden disk is 140mm diameter. Steel washer 35mm diameter.

Half threaded shaft , smooth to rotate on the inside but no difference in actual use as the bolt doesn't rotate.
4 screws for finderscope holder.
Pink/purple paint was leftover and I coated it to reduce the wooden pores trapping fungus spores and dust.

Tension adjusting wing nut , bolt shaft length was really close to estimation , any error and I would have bought too short.

Parts display.
140mm hdpe plastic disk cut from 5L dishwashing refill container $4 from supermarket
Steel washer 20 cent and more washers cut from hdpe plastic
M10 wing nut , 60 cent
M10 half threaded bolt , stainless steel 201 , $2
Small L bracket , galvanized steel , 8 for $1.40 at Mr DIY , not used in this project
Rounded L bracket , stainless steel , not used in this project
Diagonal support bracket , stainless steel , 20 cent
Philip screws 1 pack
Milk powder can or snack container lid , as sliding surface for bottom azimuth rotation
Vixen dovetail saddle clamp , $24


Tools needed.
Jigsaw , corded , dongcheng brand , about $70
Screwdriver or drill , corded , makita brand , about $50
Drill bits 2mm to 8mm starter kit , less than $10 , more 2mm drill bits to prepare hole before grease and screw , 10mm drill bit if using M10 bolt as main shaft.
Jigsaw blade , $1.50 to $2 for each pack of 5 , retail price for branded authentic much higher
Jigsaw blade T101ao narrow for curve cut - circle , t224 big wide teeth for straight cut , t118 tiny teeth cut plastic
Plastic cutter , kitchen scissors.

Design mistakes.
I based the estimation on the 50mm finderscope , cut the wood for vertical arm as low as possible to reduce weight.
When I attempted to match it with 5 inch maksutov , there isn't enough bottom clearance.
Rotating the longer azimuth arm for use as vertical altitude arm barely have enough length. No need to redo whole thing , just drill hole.
I used the corner of the wall to get the 90 degree angle , actual result wrong , on hindsight i should have used clamps and proper L brackets when screwing in the main elbow joint.
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