Jump to content

Banner.jpg.b6007b69ccdf5c69bf18273ddfe023df.jpg


1CM69
 Share

Recommended Posts

Hi all,

bit of a long post coming up in stages but I thought I'd share this as it may help out others.

A few weeks ago while I was packing away my kit I noticed that the leg clamps on my Celestron CPC tripod had cracks in them right where they join the spreader.

Two had cracks right the way through & one was halfway through. I hadn't noticed this before but have no idea how long they had been like this.

Very thankful that I spotted it before they completely gave way & my tripod collapsed with my scope etc still mounted.

image1.jpeg.4dd917d185d4490872f572289eb17f0e.jpegimage8.jpeg.47d4d9df438bc0377f40d88607a98eaa.jpegimage9.jpeg.64ea44ab254a62462578c447579a3faf.jpeg

  • Sad 1
Link to comment
Share on other sites

When I got home I did a bit of research and found various threads on CN about leg clamps cracking.

Also what I found out was that these clamps were actually plastic, all this time I assumed they were cast aluminium.

Anyway, as the scope/tripod was less than 2 years old, (Celestron's warranty length), I sent Celestron Tech an email.

They eventually got back to me saying that I would need to contact my dealer initially or failing that, the UK distributor David Hinds.

Straight away I shot off two emails, one to my dealer @FLO & also to David Hinds stating what has happened etc & also asking what to do as the sheer weight of the tripod made it uneconomic to keep shipping around after all the clamps are available to purchase for £14 each.

D Hinds responded saying that they no longer deal with retail unless the item was initially purchased from them & told me to contact my dealer.

@FLO  responded also and were absolutely brilliant, they asked me to take pictures of the tripod showing it's overall condition & send these to them including the pics of the cracked leg clamps. They would then forward these pics to D Hinds who would then make a decision as to whether this issue would be covered by the warranty.

Within a day @FLO replied and said Celestron (D Hinds) had agreed to cover the clamps under warranty & are sending them to me FOC.

A few days later the replacement clamps arrived.

IMG_1112.JPG.c03c29a520d3e0927b8305f0d091bc3e.JPG

  • Like 2
Link to comment
Share on other sites

No I set about replacing the broken clamps.

Initially I removed the 4 grub screws from each leg base hoping that they would just slide off and then similarly I could just slide off each of the broken clamps & slide the new ones on.

This didn't work, it would seem like the leg bases are secured in place by other means too, glue or press fitting etc..

Eventually I found a way to do the job.

  • remove the leg extender clamp lever by loosening it

IMG_1086.JPG.e44f08af2e06efef118115bb45d591d4.JPGIMG_1087.JPG.21271f12c26233d602b81087dbcb9e7c.JPG

  • remove the leg clamp securing bolt, washer & nut

IMG_1088.JPG.1afa04332481dec6e84785bd8ccc4402.JPGIMG_1089.JPG.76ee9a6550ee6c1c5bc3abc091da9ab2.JPG

  • carefully spread the leg clamp open & ease it down over the leg base to remove it

IMG_1090.JPG.0dd2ebe8d61870b4ef78ba1a1bb3c08d.JPG

refitting is a reversal of the above procedure but remember to leave the leg clamp bolt loose until located in the correct position with the leg spreader.

I would suggest warming the new clamps a little i.e. with a hairdryer as they are quite stiff & you do not want to risk breaking them while prising open.

Link to comment
Share on other sites

After replacing the leg clamps and seen as I had removed each leg from the tripod top in order to more easily do the job, I thought it would be wise to upgrade the joint system where the top of each leg attaches to the tripod top.

Before I even started removing each leg prior to replacing the leg clamps I did notice that these top joints were a little stiff & pulling the legs apart caused a lateral twisting movement on the leg clamps exactly where they had cracked, so it was a fatigue issue due to poor quality design/manufacture.

Also, there was excessive play in the spreader to leg clamp joints & the spreader to centre boss joints.

The original shims from the top of each leg were plastic, all differing thicknesses and pretty mangled

IMG_1091.JPG.ebf2eb47cabc25dfbd10e235528a62c1.JPG

there were no shims at either end of the spreader bars.

Edited by 1CM69
Link to comment
Share on other sites

I spent a lot of time with a feeler gauge checking & triple checking the slop in every moving joint, marking each part to match it's counterpart so I knew exactly how each part went back together.

I found that each of the leg to tripod top joint slop varied; 0.8mm, 0.9mm & 1.0mm but the spreader arms all were pretty much identical at 2.0mm.

Next was to find a simple but robust way to fix this slop.

First I thought about using PTFE/Teflon washers being as they are self lubricating but these turned out to be very hard to get in the correct sizes & were stupid money.

Eventually I went for Stainless Steel Shim Washers from ACCU & I ordered some M10 for the leg top joints & M8 for the spreader arm joints both in 0.1mm & 0.2mm

I found that Stainless Steel does not cause a galvanic reaction with the die cast aluminium of the tripod, so ideal.

The plan was to use two shims together each side of the leg top joint bolt, forming a basic shim bearing and to lubricate it with graphite powder.

The spreader arm joints would just need a single washer each side of threader spacer as they were purely there to take up the extra slop.

Shims duly arrived. 

IMG_1100.JPG.498a936504ac3d7044f99980b15db2a7.JPG

Link to comment
Share on other sites

Very simple task of putting the tripod back together with all shims in situ.

Last job was tightening the leg clamp bolts when I had made sure they were all in the correct place.

Graphite powder, well that's another story, bleeding stuff gets everywhere & wouldn't stay where I wanted it. Yeah, very good lube but too messy.

In the end I lubed all the moving joints with dry PTFE spray & will keep this up as regular maintenance.

Here's a short video showing just how easily the tripod now operates.

 

Thanks for reading..,

Kirk

Edited by 1CM69
  • Like 1
Link to comment
Share on other sites

48 minutes ago, Grant said:

Excellent write-up Kirk - very useful information :)

Thanks Grant

6 minutes ago, JohnSadlerAstro said:

It's good you got the issue sorted out in the end--FLO are where it's at with customer service! :)

John

It was definitely a Phew moment & yes @FLO are great when it comes to CS

  • Like 1
Link to comment
Share on other sites

  • 4 years later...

In case someone stumbles upon this thread looking for a solution, I have designed a 2-piece clamp for 3D printing that seems to fit.  Whether it will do the job remains to be seen, and I'll be testing it this weekend.  Photos attached.

Once I know this isn't likely to dump someone's expensive scope on the ground, I will post the design online.

new_installed.png

old_and_new.png

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.