Arborist blocks parts and designs

[combrig]

I really need help with that. This kind of equipment is not available on the market in my country, so I have to manufacture it myself. It is quite expensive, but compared to ordering the block from USA it is relatively cheaper.
I decided to use stainless steel for the plates and the pins and aluminum alloy for the sheaves. I will use ball bearing for the bigger sheave and bronze or plastic bushing for the small sheave. One of the plates can be rotated (opened), while the other is fully static.
The problem, that I've encountered is with the spindle of the small sheave. It is important that the small sheave remains ON the block when the block is opened. Unfortunately, the pictures and YouTube videos didn't provide me any information on that how it can be done . I have a few ideas, but it's better to ask first so...
Can you make a pictures of the blocks that you are using and explain how exactly they are designed? I know, that maybe the design is licensed or something, but after all I don't intend to make hundreds of blocks... Just one.

Thank you!

P.S. Sorry if this thread isn't for this forum.

 

[MasterBlaster]

Wow, I can't imagine fabricating a block. I'd bite the bullet and pay the shipping, myself - but good luck! Perhaps someone here can help!

 

[combrig]

Well, I cannot do it all by myself, because I do not have machines like milling machine or lathe, but I will pay someone who has. There are materials on the market...
The design shall be mine, though

 

[Altissimus]

... I think Butch may be right ... wow Bulgaria, maybe shop around for some used not abused gear to save some dough ... check here maybe TreeBuzz but be careful not get screwed maybe check EBay too

 

[combrig]

Well, maybe you are right. I thought about that - after all the blocks on the market are certified and tested by the manufacturer. The thing that I will design, in the best case will be heavier (don't know if stronger) than ones from the shop. And I do not even want to think about the worst case scenario, where something can break while negative rigging.
But I am pretty confident that Solid Works calculations, good material quality and keeping the work light will do the job. At least for a while, till I find some friend, agree to send/bring me some blocks.

Well, that does not change the fact that I am interested how the manufacturers solved the "problem" with the small sheave staying on the plate while the block is opened...

 

[MasterBlaster]

It's almost like making your own rope... I don't know how much I'd trust it!

 

[Bermy]

What about getting hold of Maximalist...he's in Russia, ok St. Petersburg, quite a long way away, but maybe he has an idea of a more local/regional supply of rated equipment?

 

[RopeArmour]

http://www.freeworker.de/freeworker/

Good people with good tools! They have everything you would need for tree work plus more, including RopeArmour

 

[stig]

Or try one of the English suppliers, like Honey Brothers.
Shipping stuff within Europe is WAY cheaper than getting it from the US.
I only buy in the US when I buy bulk.We just recieved a saddle, a rope, an ascender and a croll from Honey Brothers today, shipping was 13,77£.

 

[combrig]

I will definitely think about that. I noticed Honey Brothers website and I will write them to see what the ETA and estimated price of the shipping will be.
Is there a major difference between HB prices and US prices?

 

[stig]

Things seem to be a good bit cheaper in the US, but not enough to make up for the difference in shipping costs.
Unless, like I said, you really buy big.

 

[Reddog]

Some just use a pin that then rotates to lock in place.

 

[combrig]

And, just by the way, can someone really explain to me how exactly the small sheave stays in place when the block is opened? I saw that there are to types of locking the two plates - with spring and with thread... Does that somehow affect the way that the sheave stays in place?

 

[Reddog]

The same roll pin that locks the plates holds the sheave from coming off.

 

[combrig]

Thank you I will see it when I get my first block Any suggestions what should I buy? I was looking for CMI 3/4 & 5/8 blocks - one of each...

 

[bonner1040]

If you plan to change the sling on the block, or rotate slings between hardware the spring blocks are nice.

These and other ISC blocks are high quality and in the range you describe.
http://www.honeybros.com/index.php?...f=ISC_100kN_Small_Cast_Aluminium_Pulley_RPO51
http://www.honeybros.com/index.php?...=ISC_150kN_Medium_Cast_Aluminium_Pulley_RPO55

CMI blocks are good quality and some of the most affordable on the market. However this is a pulley not a block and not really designed for impact loads.
http://www.honeybros.com/index.php?app=ecom&ns=prodshow&ref=CMI_Stainless_Steel_Pulley

I couldnt find the CMI Blocks on HB, but here are some reference links to a US distributor
https://www.treestuff.com/store/catalog.asp?category_id=235&item=1505 ( I have this block and while not 'full featured' its a hell of a bargain at $90USD, I also have the small ISC block and it is much nicer though but not necessarily more functional).

2 other options from CMI
https://www.treestuff.com/store/catalog.asp?category_id=235&item=139
https://www.treestuff.com/store/catalog.asp?category_id=235&item=130

 

[NickfromWI]

Just buy one. You said you can compensate for the questionable strength by keeping the work light. The whole point of a block is that you don't HAVE to keep the work light. You seem to be talking about making your crew work slower so you can save $100 on a block.

Bite the bullet and get the real deal. It'll pay for itself.

 

[combrig]

Well, I think that you are right.. After all you have much more experience than me. I am going for factory-made block.
It won't be DMM for sure (financial reasons), but there are other options on HB.

 

[High Scale]

Bulgaria, one of the only places I feared for my life.

 

[combrig]

It's hard to believe that it's part of the EU, isn't it? But the biggest problem for me now is that we do not have an arborist equipment store here...

 

[Altissimus]

..... any used Marine equipment dealers there? ... another source maybe to save money on Blocks

 

[combrig]

It's an interesting idea, I have to check!
Just received a letter by the Bulgarian company, that imports DMM's sport products. They told me, that they will give me prices for the DMM's blocks within few days. If the price si OK, I will go DMM (small one).

 

[Bermy]

Good result!