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Question about wooden tripods

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#51 PawPaw

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Posted 16 March 2021 - 08:07 AM

The hardest wood known is lignum vitae with a janka hardness rating of 4300. Ipe is around 3600, purpleheart, brazilian cherry, and bloodwood are all near the top at 2500 to 3000. By comparison, white oak ( a pretty hard wood) comes in at 1360, ash at 1320, and cherry far below that at 950.

 

Osage orange may be harder to find but it is available.  There are several bowyers in the midwest who purchase straight staves for making bows.   I can personally attest to its durability as I have these trees growing on my property.  I am still cutting firewood from broken limbs from a 2001 ice storm that devastated our trees.   The limbs did not fall from the trees like the other species  but the fibers split under the immense weight of the ice and stayed connected to the tree.   They are famous here in the midwest for fenceposts and I have removed posts from a fencerow that was built in the early 1900's finding the wood still intact but so hard you are unable to drive a fence staple in. 

 

Osage orange (Bois D'arc) Janka rating is 2650. 

 

Osage Orange has a relatively low modulus of elasticity compared to its weight and modulus of rupture  which helps explain why it is sometimes used for archery bows. It’s sometimes called Bois d’arc, which literally means “bow wood” in American French.The wood is also very stable, with little seasonal/environmental movement.

 

Common Name(s): Osage Orange, Horse Apple, Hedge Apple, Bois d’arc

Scientific Name: Maclura pomifera

Distribution: South-central United States

Tree Size: 50-60 ft (15-18 m) tall, 1-2 ft (.3-.6 m) trunk diameter

Average Dried Weight: 54 lbs/ft3 (855 kg/m3)

Specific Gravity (Basic, 12% MC): .76, .86

Janka Hardness: 2,620 lbf (11,640 N)

Modulus of Rupture: 18,650 lbf/in2 (128.6 MPa)

Elastic Modulus: 1,689,000 lbf/in2 (11.64 GPa)

Crushing Strength: 9,380 lbf/in2 (64.7 MPa)*

 

By the way I like the design you are thinking about.

 

Cheers

 

Don


Edited by PawPaw, 16 March 2021 - 08:08 AM.

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#52 walter a

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Posted 16 March 2021 - 09:02 AM

I actually spent quite a bit of time looking at surveyor's tripods. I love them, they're functional and they have character. Unfortunately, every creative type with an etsy store is buying them and turning them into lamps apparently, so now old surveyor's tripods are going for $200-$300.

I got lucky and found a tripod basically nos still in the box for 40.00 I still had to laminate a tray up for it and is now quite rigid.

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#53 PawPaw

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Posted 16 March 2021 - 09:29 AM

Walter that is a solid looking tripod.....your tray looks like oak.....what type of wood are the legs?



#54 walter a

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Posted 16 March 2021 - 10:06 AM

Thanks Don, the tripod looks like white ash. I had someone come in the shop in need of a replacement arm rest on a antique chair. So after making a new one they gave me the left overpieces that I used to make the tray. I thought it may be oak as well till I stained it with lite oak stain and it turned a reddish color so now I am not sure. These were very old and very hard boards.


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#55 Pete W

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Posted 16 March 2021 - 10:30 AM

Love this topic...



#56 Terra Nova

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Posted 16 March 2021 - 10:53 AM

The hardest wood known is lignum vitae with a janka hardness rating of 4300. Ipe is around 3600, purpleheart, brazilian cherry, and bloodwood are all near the top at 2500 to 3000. By comparison, white oak ( a pretty hard wood) comes in at 1360, ash at 1320, and cherry far below that at 950.

 

Osage orange may be harder to find but it is available.  There are several bowyers in the midwest who purchase straight staves for making bows.   I can personally attest to its durability as I have these trees growing on my property.  I am still cutting firewood from broken limbs from a 2001 ice storm that devastated our trees.   The limbs did not fall from the trees like the other species  but the fibers split under the immense weight of the ice and stayed connected to the tree.   They are famous here in the midwest for fenceposts and I have removed posts from a fencerow that was built in the early 1900's finding the wood still intact but so hard you are unable to drive a fence staple in. 

 

Osage orange (Bois D'arc) Janka rating is 2650. 

 

Osage Orange has a relatively low modulus of elasticity compared to its weight and modulus of rupture  which helps explain why it is sometimes used for archery bows. It’s sometimes called Bois d’arc, which literally means “bow wood” in American French.The wood is also very stable, with little seasonal/environmental movement.

 

Common Name(s): Osage Orange, Horse Apple, Hedge Apple, Bois d’arc

Scientific Name: Maclura pomifera

Distribution: South-central United States

Tree Size: 50-60 ft (15-18 m) tall, 1-2 ft (.3-.6 m) trunk diameter

Average Dried Weight: 54 lbs/ft3 (855 kg/m3)

Specific Gravity (Basic, 12% MC): .76, .86

Janka Hardness: 2,620 lbf (11,640 N)

Modulus of Rupture: 18,650 lbf/in2 (128.6 MPa)

Elastic Modulus: 1,689,000 lbf/in2 (11.64 GPa)

Crushing Strength: 9,380 lbf/in2 (64.7 MPa)*

 

By the way I like the design you are thinking about.

 

Cheers

 

Don

We have them all over here in Kentucky. I enjoy collecting the green ‘oranges’ when they fall in the Autumn and putting them in a basket. The heavy grapefruit sized fruits are inedible although birds and small animals enjoy the seeds; they have a faint citrus odor. My family in Mississippi always referred to them as ‘bodock’ trees, which is what I always called them until the ‘northerners’ up here educated me otherwise; they had no idea what I was talking about, and when I pointed one out they said, “those are Osage oranges!”. :lol:


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#57 PawPaw

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Posted 16 March 2021 - 11:39 AM

We have them all over here in Kentucky. I enjoy collecting the green ‘oranges’ when they fall in the Autumn and putting them in a basket. The heavy grapefruit sized fruits are inedible although birds and small animals enjoy the seeds; they have a faint citrus odor. My family in Mississippi always referred to them as ‘bodock’ trees, which is what I always called them until the ‘northerners’ up here educated me otherwise; they had no idea what I was talking about, and when I pointed one out they said, “those are Osage oranges!”. lol.gif

I can sympathize Terra.....around my "neck of the woods" if you don't call them Hedge trees you get that look.  In our area you find the Osage Orange growing scattered as a native tree but also in old farm field edges or rows.  Osage orange has  a long and storied history and is native to Texas, Oklahoma and Arkansas region.  The wood of these trees was prized by Native Americans.  Hedge apple trees were used by early settlers as a living fence and were spread across the prairie and planted in hedges in the mid-1800s.  This greatly expanded the distribution of hedge apple and is the reason they are still commonly found in wooded field borders...Hence the name "Hedge tree or Hedge apple".

 

The tree is an amazing wood and it re-sprouts rapidly if you cut a live tree or even part of a live tree.  The sap is a sticky white almost looks like Elmer's glue.  As you said the seeds and center part of the fruit becomes a main food source for squirrels, rabbits and birds.

 

To keep with this thread I have always wanted to build a tripod out of the wood.  It is an amazing bright yellow color when freshly cut and turns to a  golden dark  brown patina when left to air dry.


Edited by PawPaw, 16 March 2021 - 11:45 AM.

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#58 PawPaw

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Posted 16 March 2021 - 12:03 PM

I do not know the seller but ran across some Osage Orange wood staves on ebay.  Based out of Nebraska looks like he sells multiple lengths this one is 63" long.  

 

https://www.ebay.com...8YAAOSwlYtgSFdX

 

Cheers

 

Don


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#59 godelescher

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Posted 16 March 2021 - 12:21 PM

Anyone know the width of the lugs on a GP? I need to know how wide to make the center sections of the legs.

 

Thanks



#60 walter a

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Posted 16 March 2021 - 01:29 PM

SP looks like 1 1/4 I dont know if it's the same as a GP.


Edited by walter a, 16 March 2021 - 01:30 PM.


#61 godelescher

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Posted 16 March 2021 - 06:10 PM

Picked up 8 b.f. of purpleheart today. The three long blanks are for each leg assembly. I want to cut the left, right, and center section of each leg from the same blank so, if the wood does move, it will all move in the same direction.

 

I milled it to 7/8". Without having the mount hub here, I don't know if the lugs limit the thickness of the wood, but I think I can mortise out anything that's too thick at the hub.

 

I ordered a lot of the hardware I expect to need this morning, so that should be here... well, whenever it gets here, I guess.

 

I'll post some pictures along the way.

 

Thanks, Walter, for the lug dimensions. I'm sure the GP is the same because I can't imagine Vixen changed its castings for what is otherwise an identical mount, but I'd really, really like someone to confirm that for me before I start cutting up this purpleheart. If I haven't heard otherwise by morning, I'm going with Walter's measurements.

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Edited by godelescher, 16 March 2021 - 06:56 PM.

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#62 nowhere

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Posted 16 March 2021 - 06:41 PM

I'm using oak for the legs that I've almost finished - mostly because it was readily available at a local yard with clear straight grain and the correct dimensions for my project. They're imitations of the one-piece, non-adjustable wooden legs Takahashi uses. The hardest part of that design is cutting the notch at the top of the leg that allows attachment to the mount head lugs. Since I don't have a big mounted disc sander rounding the tops of the legs off has been no picnic either. I used the saw to approximate the radius with several cuts and then used a rasp to round it off and am now at the stage of smoothing it all out with my little quarter sheet Makita sander. I have to do most of the work out on the front driveway too, which means waiting for decent weather and it kinda rains a lot here in the Vancouver area.


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#63 godelescher

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Posted 16 March 2021 - 06:53 PM

...The hardest part of that design is cutting the notch at the top of the leg that allows attachment to the mount head lugs...

If you have a table saw, you can buy a toothless disc upon which you can attach adhesive backed sandpaper. It works great for sanding radii onto outside curves.


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#64 walter a

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Posted 17 March 2021 - 05:24 AM

A redo of the SP and I get 34mm=1.33in. Good luck with your project.


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#65 apfever

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Posted 17 March 2021 - 12:36 PM

I miked my SP and regular Polaris which have different hub designs but had the same leg tang width if that is any consolation.  Averaged 1.342" on the hub casting as well as the leg spread.  That's still 34mm.  Also equals 1-3/8" shy  (1-11/32"). Variance of 0.003" or so.  This also covered three different leg designs (measured one SP and two Polaris)

 

Maybe someone can get GP specs, all I have is the SP and Polaris.  So hey folks,  just a tape measure would confirm with a close look if anyone has a GP.  1-3/8" shy?


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#66 pakman2

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Posted 17 March 2021 - 01:49 PM

I miked the hub on my GP2 mount and it was 1-11/32".


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#67 godelescher

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Posted 17 March 2021 - 03:57 PM

I miked the hub on my GP2 mount and it was 1-11/32".

 

 

I miked my SP and regular Polaris which have different hub designs but had the same leg tang width if that is any consolation.  Averaged 1.342" on the hub casting as well as the leg spread.  That's still 34mm.  Also equals 1-3/8" shy  (1-11/32"). Variance of 0.003" or so.  This also covered three different leg designs (measured one SP and two Polaris)

 

 

 

 

A redo of the SP and I get 34mm=1.33in. Good luck with your project.

Thank you very much. I cut the center sections 1.355" (+/- .005"). I figure I'll lose a bit to sanding and I can shave it if it's still too fat, but I think it will be pretty close to good.

 

OK, one last question and then I'll quit asking for help:

 

At full extension, how long are your tripod's legs? And, is that a good height for you? Do you wish it was taller? How much taller?



#68 photoracer18

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Posted 17 March 2021 - 06:28 PM

My 1950s Edmund 4" F15 came on a beautiful Maple tripod:

 

attachicon.gifEdmund 4 - OTA Done (Mounted) S04.jpg

 

Sturdy, very fast damping time, and I could carry the whole rig short distances around my back yard -- the LONG scope caused more off-balance issues while toting than the tall tripod.

I collected parts off the forums and the used dealers to make this last year for my AP400QMD.

 

AP400 tripod.gif

 

Have not decided on a new finish yet, drilling eyepiece holes in the tray or fitting spikes /rubber feet to the legs.


Edited by photoracer18, 17 March 2021 - 06:34 PM.

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#69 nowhere

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Posted 17 March 2021 - 08:46 PM

If you have a table saw, you can buy a toothless disc upon which you can attach adhesive backed sandpaper. It works great for sanding radii onto outside curves.

I had no idea that was possible - and I do have a tablesaw! Thank you so much. This is going to make a few things so much easier!



#70 godelescher

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Posted 17 March 2021 - 08:50 PM

By the way, this is the compromise for clamping the legs. This picture is just using things I have lying around. A 1/2" bar 3/16" thick, drilled and tapped for a 1/4-20 knob. The actual bar will be more like 12"-16" long. This should glide better and give more even pressure when clamped.

 

 

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#71 godelescher

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Posted 19 March 2021 - 12:11 PM

Update:

 

Legs pieces are milled.

 

I made some design changes that I think will improve the stability. The outer legs will have .5" x .125" aluminum bar stock fastened to the tenons to ride in the T-slots.

 

The outer leg length is 40" and the center extension increases the length to 60".

 

The upper most portion of the center section is permanently fixed in position to stiffen the whole leg assembly. Only the bottom 28" extends. I did this because fully collapsed, the height works for me using the Vixen 80fl from a chair. At full extension, it will work for me using a long FL refractor.

 

Also, when fully collapsed, all of the pieces of each leg are grain matched and look like a single solid plank. There are only 12 pieces total, but an infinite number of ways to screw that up either in milling or assembly. I did this not only because grain matching looks nice, but also because I want the whole leg to be stable. If it decides to twist or move, I want the whole leg to twist or move with it.

 

I'm still waiting on clamping hardware and I'm still trying to source Surveyor feet, but I'm not having any luck with that. Some of the hardware is supposed to arrive tomorrow and some on Tuesday, The most important part, the machined T-slot bars are coming from Canada and won't be until the end of next week at the earliest. Until then, I guess I'm working on a spreader, radiusing the upper legs, and sanding.

 

I also want to give a shout-out to Defenderslideguitar who was able to provide me with a hub for the mount, Thank you again!

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Edited by godelescher, 19 March 2021 - 07:01 PM.

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#72 godelescher

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Posted 19 March 2021 - 12:12 PM

Photos are too big to fit in one post, so here's another one

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Edited by godelescher, 19 March 2021 - 12:13 PM.

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#73 Terra Nova

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Posted 19 March 2021 - 01:07 PM

Wow! That’s some really nice work!


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#74 Kasmos

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Posted 19 March 2021 - 05:41 PM

waytogo.gif Yes, Very Nice!... and the neat addition of the aluminum is a cool choice. It reminds me of something you might see on a piece of well made contemporary furniture.

 

I suppose I'm bias but seeing all that purpleheart is awesome!


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#75 godelescher

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Posted 19 March 2021 - 07:23 PM

I suppose I'm bias but seeing all that purpleheart is awesome!

I wouldn't have thought of purpleheart if it wasn't for the picture of your tripod. I should thank you. My saw blades aren't real happy, but I am.


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