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Archive 2007 · Feisol CT-3371 Spike Modification

  
 
sjms
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p.1 #1 · Feisol CT-3371 Spike Modification


about a week or so ago it was mentioned that the available spike setup for the CT3371 was lacking in good design qualities. it was also mentioned that its design brought about cracking in the base aluminum attach point due to the poor loading characteristics. in short the design sort of sucked overall. when i first got mine back almost 2 years ago i also got a single spike for the monopod. i took one look at it and tossed it aside as a definate no go product. i did a review on this site (now archived somewhere) and mentioned that i felt the spikes were not a happening part of the setup and were not advised. i generally don't use spikes on this tripod due to its use on nice wood floors and such. but last weeks update on the issue finally got me to rethink the problem.
i had an idea for a long time but never followed up on it. then "therock" contacted me and we discussed it and came to the conclusion that there was a fix. he being a fine machinist and had access to the needed tools produced what seems to be the only available proper combination of sizes in a stainless steel bushing (custom made) that would help in the resolution.

image 1 the issue. thin wall aluminum threaded base cap. this is usually covered by a rubber boot. for the 90% of those you never see it.
http://i.pbase.com/g3/89/44489/3/90004875.Gk1P1QcB.jpg
image 2 the bushing being put into place. i chose to loctite it in to the base using the red type somewhat permanent locktite in stick form. sorta like a glue stick as i have no intention of removing it
http://i.pbase.com/g3/89/44489/3/90004876.HzBun2YP.jpg
image 3 the SS bushing in place and curing for 24 hours
http://i.pbase.com/g3/89/44489/3/90004877.skjTXnrv.jpg
image 4 this shows the way the bushing fits over the GITZO 1.5" spikes (item #G1220.129B3 set of 3 with all required washers and spike boots included in the package)
http://i.pbase.com/g3/89/44489/3/90004966.a0TsOaWS.jpg
image 5 finished product. also yes if you want to use the gitzo extra long 4.7" foot impalers they will work also
http://i.pbase.com/g3/89/44489/3/90004878.jERGkAyG.jpg
image 6 the finished product with boot in place
http://i.pbase.com/g3/89/44489/3/90004965.QKt184Tk.jpg

what is the reason for the heavy duty alloy washer and why is supplied with the spike package from gitzo? it serves 2 purposes:
1- as the base connection on my Gitzo GT2540EX tripod is subject to the same loading as in the feisol. the washer spreads the load over the entire base contact area and helps prevent the threading from getting blown out by dropping the tripod down with a good effort. on the larger tripods the larger washer spreads any side loading over the entire diameter of the tube. an excellent load spreader a stopper
2- a good platform for an excellently designed spike boot

the one small problem: the thread on the feisol is a metric M7 thread and the thread on the gitzo spikes are a 3/8-16 thread. in stainless bushings at this point that combination is not available that could be found as of this date. they are available in carbon steel but that is counter productive to its locational use due to its tendency to oxidize when in a wet zone and that area is a definite wet zone. so "therock" hand milled, drilled out and tapped a few 316SS M7 bolts to spec and produced a set outstanding SS bushings. get to know your neighborhood machinist.

a big thank you to "therock" for his input and output in this project





Edited by sjms on Dec 07, 2007 at 08:43 PM GMT



Dec 07, 2007 at 10:53 AM
Billdev
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p.1 #2 · Feisol CT-3371 Spike Modification


Thanks for posting this info. I just received my CT-3371 yesterday, and I am very interested in making this modification to it before putting it into use. I have PM'd "therock" to ask if he is interested in selling me a set of the SS bushings.

Thanks again.

Bill



Dec 07, 2007 at 03:30 PM
dcains
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p.1 #3 · Feisol CT-3371 Spike Modification


Nice work. For my Gitzo G1228LVL I had a friend, also a skilled machinist, duplicate the type of spike setup which used to be sold by Markins. SS, though, not titanium.


Dec 07, 2007 at 08:51 PM





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