Cutting down a Skywatcher 1.75” tripod

[PadrePeace]

I had been looking for a light but super sturdy tripod for my mobile flyaway rig.  I had unfortunately missed the opportunity to get one of iOptron’s 1.5” ‘field’ tripods which weigh-in at only 3.8kg before they were discontinued and replaced with the Literock range which, if you can get one on its own,  are way too expensive and heavier with it.  
 

So I decided to set about cutting my existing 3/8” Skywatcher 1.75” tripod down to see how that might suit. The following covers how I did this with images to show the key parts of the process. Hope this is useful to someone out there.

First things first, I wanted to get the end result in my 25kg sized suitcase and because I use Sharpcap to polar align I didn’t need to worry too much about final mount height. 
I planned to take 18” off of each top tube leaving a min height of 20” and a legs extended max height of 32”. In the first image (end result) this is as low as this rig can possible get as the retracted tubes are pushed hard up into the top tubes if that makes sense. 
 

Start by removing each leg from the tripod cast aluminium head by removing the three bolts. Once the legs are free mark up each leg at the TOP with a marker pen at the cut point you have personally chosen. I removed a total of 18 inches from the TOP of each leg (over two separate mod events) which includes the 2 inches that is inside of the top hinge casting. This saved me 1.8kg. 
WARNING: extend the inner leg and lock it before cutting each leg at the required point. If you don’t do this you will risk cutting through the bottom leg extension also. 
 

Mount each leg securely in a vice or workmate and use a circular disc cutter to cut through each leg following the marker pen line to ensure a nice square cut. Wear goggles and beware sparks coming upwards from the cut!!!! Just saying.
Remove the four grub screws in the top hinge casting. I found my stainless legs were originally glued into the casting so you’ll have to heat an oven to 200C and soak the three top end pieces for 5 mins in order to soften that glue. Once soaked handle each leg in turn with oven gloves to guard against serious burns. Mount each leg in turn on your vice and put a long shank screwdriver through the casting bolt hole and rotate the casting back and forth of off the stainless leg stump. Discard the stumps. Interestingly, I found that the legs comprise of an inner mild steel tube dressed with a thin stainless steel outer. BEWARE: the screw driver shaft will also be seriously hot once used so please do guard against burns at all stages.  I personally would not use a bare flame to heat these bits as I think that would risk damaging the white paint on the alloy castings or the alloy casting itself. Oven baking to 200C both accurately controls the max temp applied and does not impact the paint or indeed the ‘N’ leg sticker at all. 
 

ONCE COOL…. Lightly clean up the hinge casting inner faces with a small dremel tool or grind stone wheel and Emory paper. This is soft alloy so don’t overdo it. It has to be a snug fit. Disc grind a shallow chamfer on to the top of each shortened stainless steel leg to remove any burrs left over from cutting and to help it to slide into the hinge casting.

I put three very light smears, no more, of gorilla glue inside the casting and lightly misted the top of each stainless tube with water to help it slide in and to activate the glue once it’s all pushed nicely together. Refit the four grub screws in each casting and tighten lightly but securely. Too tight and you’ll strip the threads. These along with the expanding gorilla glue will be enough to fix each leg joint. 
Finally remount the three legs onto the tripod head and torque up the joints to taste. 

My tripod ended up at 4.7kg incl the spreader brace and 3/8 bar. 
 

Last point, making theses modifications will kill your warrantee….🥱

Clear skies to you. 

Edited June 12, 2022 by PadrePeace

[NGC 1502]

Just read with interest 👍

Looks like you have a nice work shop, former garage?   The floor looks remarkably clean, is it always as pristine as that?  Mine sure isn’t, usually a dog’s dinner after several jobs without a proper tidy….!!

Ed.

[Alan White]

A very nice neat and tidy job, but as Ed says above,
with such a tidy workplace, then tidy work should be produced.

[Swoop1]

Very nice job @PadrePeace

One thought I have just had- would forgoing the Gorilla Glue during reassembly and relying on the grub screws still produce a secure enough fit but allow stripping down even further into a smaller bag?

[PadrePeace]

3 hours ago, NGC 1502 said:

Just read with interest 👍

Looks like you have a nice work shop, former garage?   The floor looks remarkably clean, is it always as pristine as that?  Mine sure isn’t, usually a dog’s dinner after several jobs without a proper tidy….!!

Ed.

This is a working car garage for our two cars. Had the floors painted to seal the cement dust in but I appreciate the compliment all the same. 

[PadrePeace]

2 hours ago, Swoop1 said:

Very nice job @PadrePeace

One thought I have just had- would forgoing the Gorilla Glue during reassembly and relying on the grub screws still produce a secure enough fit but allow stripping down even further into a smaller bag?

I really doubt the grub screws will hold the legs on their own. Also, continued loosening and tightening will wear the threads so I’d stick with the glue. That’s very likely why Skywatched has.