Blob60

[com202]

It would potentially be possible to create a blob where the top and bottom are two different sizes. There would be a step in the middle where the seam was located but that could be tapered to minimize the sharp edge. Picture a blob with a Blob50 top and a Blob40 bottom (weight probably around 45#). It would also be possible to have a one inch steel bar placed in the sand mold so that when it was cast you would have six inches or so of bar sticking out of each side to add weight.

I would buy one of these.

[tja]

It would appear from the BC’s FAQ measurements that while the diameter increased by .5” from the 45 to the 50 the width increase was minimal and there was no increase in the Flare. The variation in the numbers makes the determination of a “BLOB Constant” or ratio very difficult.

The constant for grey iron is 0.260 lbs per cubic inch.

Perhaps someone with better math skills than I can take a crack at this problem

I think the easiest way to measure the volume would be sink the blob into a container filled to the top with water. Then collect the displaced water and measure the volume.

[GordonV]

So far the best answer to the situation was sent by Chris Ryan via PM. It essentially provides the math to figure out the BLOB60 sizes under choice number 3.

per Chris Ryan:

The math SHOULD be fairly simple, to wit: increase all linear dimensions by the third root of 20%, which would be roughly 2.7%--that would be option #3, and the one that has my vote, to be selfish. Increasing the diameter only, while keeping the widths the same should involve only increasing the diameter by the square root of 20%, or about 4.47%. Increasing width only is simply linear: 20% increase, with all other dimensions the same. One of the engineers on the gripboard surely has some kind of CAD morphing software that could come up with a 3-dimensional model that someone else could feed into a CNC milling machine, and there's the positive to make the mold from...in a perfect world.

************************

I've only read it and not done the calculations using the Blob numbers above. It makes sense to me that the theoretical math works this way, anyone have CAD to draw up a picture?

[GordonV]

So I did the math and the using Option 3 the size of the BLOB60 would be D 7.638313 W 3.979625 F 5.6485

Versus Option 1 which would be D 7.769956 W 3.875 F 5.5.

In other words the Top width of the #60 would be .112625 or a little less than 1/8th of an inch wider at the top with the same flare profile and texture as the #50.

[vikingsrule92]

I think we should go for option 3 then. When I first answered option 1 I didn't think about how that would be just as easy as a Blob+10.

[Sean Dockery]

I'd buy and option 3 is the only way to fly in my opinion.

[MalachiMcMullen]

Ok, it's not THAT much bigger than the blob50 I suppose and I'd still buy so I guess I'm good with any option.

[GordonV]

It's been a while since I posted anything so I figured an update would be appropriate.

The BLOB60 and DWBLOB project continues to move forward. I have an engineer working on 3D CAD drawings so we can get the weight as close to perfect as possible. The problem is he is working on it in his free time at work and has been swamped with other projects. I hope to have the files in the next week or so then it is off to the foundry to have the patterns made and begin production.

Based on how things are presently progressing the 60's will likely be available in April.

[Cannon]

It's been a while since I posted anything so I figured an update would be appropriate.

The BLOB60 and DWBLOB project continues to move forward. I have an engineer working on 3D CAD drawings so we can get the weight as close to perfect as possible. The problem is he is working on it in his free time at work and has been swamped with other projects. I hope to have the files in the next week or so then it is off to the foundry to have the patterns made and begin production.

Based on how things are presently progressing the 60's will likely be available in April.

Hey, Gordon, what's the DWBLOB?

[egg_uk]

i think its discussed earlier in this thread, i think it stands for double width blob, each half is a different width, ie it could be the width of a 45 on one half and 50 on the other half, something like that.

[cptnamazin]

should my financial situation at the time of production allow for it, i'd like to buy a blob60. dunno for sure yet though.

Edited February 4, 2008 by Captain Amazing

[coreylan]

Hey guys-

I stink at lifting block weights but I am decent at math. I came up with a general formula for calculating the weight of a Blob given the dimensions listed (a cylinder with spherical dome endcaps). Actually I just pulled the essential stuff from here http://www.monolithic.com/construction/formulas.pdf and modified your dimensions to be compatible with the formulas. However, I found that the calculated weight of the Blob differed from the stated weight of the Blob, sometimes fairly significantly. Using the measurements I calculated:

30# blob: 31.69# calculated

35# blob: 37.04# calculated

40# blob: 42.76# calculated

45# blob: 45.92# calculated

50# blob: 53.10# calculated

I made a spreadsheet where you just punch in D,W,and F and it spits out the weight. I am very confident the spreadsheet is correct, but the problem is that it gives 2-7% higher weights than is stated. As far as I can tell, this means one of 3 things:

-The blobs are cast with varying types and densities of cast iron

-The blobs may actually have a somewhat different geometry than assumed for the calculations

-There could be measurement errors of some flavor or another

I've never seen or tried to lift an actual Blob so I don't really know much about them. Are they generally pretty uniform or do the weights vary?

Edited February 5, 2008 by coreylan

[vikingsrule92]

The weights vary to some extent, usually from around 50-53 from what I've heard.

[gaster]

Hey guys-

I stink at lifting block weights but I am decent at math. I came up with a general formula for calculating the weight of a Blob given the dimensions listed (a cylinder with spherical dome endcaps). Actually I just pulled the essential stuff from here http://www.monolithic.com/construction/formulas.pdf and modified your dimensions to be compatible with the formulas. However, I found that the calculated weight of the Blob differed from the stated weight of the Blob, sometimes fairly significantly. Using the measurements I calculated:

30# blob: 31.69# calculated

35# blob: 37.04# calculated

40# blob: 42.76# calculated

45# blob: 45.92# calculated

50# blob: 53.10# calculated

I made a spreadsheet where you just punch in D,W,and F and it spits out the weight. I am very confident the spreadsheet is correct, but the problem is that it gives 2-7% higher weights than is stated. As far as I can tell, this means one of 3 things:

-The blobs are cast with varying types and densities of cast iron

-The blobs may actually have a somewhat different geometry than assumed for the calculations

-There could be measurement errors of some flavor or another

I've never seen or tried to lift an actual Blob so I don't really know much about them. Are they generally pretty uniform or do the weights vary?

Your formulas seem pretty much spot on, but there are 2 small things you may be missing. 1. The flat spot on the bottom. Maybe that takes away a bit of material and weight. 2. The small radius between the cylinder and spherical dome end caps. That small amount of removed material could make a difference.

That's a great overall job though, it's more close mathematically than I've seen before.

[coreylan]

Hey guys-

I stink at lifting block weights but I am decent at math. I came up with a general formula for calculating the weight of a Blob given the dimensions listed (a cylinder with spherical dome endcaps). Actually I just pulled the essential stuff from here http://www.monolithic.com/construction/formulas.pdf and modified your dimensions to be compatible with the formulas. However, I found that the calculated weight of the Blob differed from the stated weight of the Blob, sometimes fairly significantly. Using the measurements I calculated:

30# blob: 31.69# calculated

35# blob: 37.04# calculated

40# blob: 42.76# calculated

45# blob: 45.92# calculated

50# blob: 53.10# calculated

I made a spreadsheet where you just punch in D,W,and F and it spits out the weight. I am very confident the spreadsheet is correct, but the problem is that it gives 2-7% higher weights than is stated. As far as I can tell, this means one of 3 things:

-The blobs are cast with varying types and densities of cast iron

-The blobs may actually have a somewhat different geometry than assumed for the calculations

-There could be measurement errors of some flavor or another

I've never seen or tried to lift an actual Blob so I don't really know much about them. Are they generally pretty uniform or do the weights vary?

Your formulas seem pretty much spot on, but there are 2 small things you may be missing. 1. The flat spot on the bottom. Maybe that takes away a bit of material and weight. 2. The small radius between the cylinder and spherical dome end caps. That small amount of removed material could make a difference.

That's a great overall job though, it's more close mathematically than I've seen before.

That makes sense. I didn't realize there was a flat spot on the bottom and whatnot. I imagine the original dumbbells were made using trial and error to get the weights they wanted and of course they never thought a bunch of grip guys would be scrutinizing their work like this heh.

Looking at the diagram in the pdf I linked, you see that r = D/2 and h = (F-W)/2, and your blob volume is

Volume = (Volume of center section) + (Volume of endcaps) or

Volume = (Pi)r²W + (1/3)(Pi)h(3r² + h²)

so to get weight, multiply the volume by the density (0.260).

That's what I did anyway. It wouldn't be difficult to adjust for flat spots on the ends and whatnot.

[Andy]

The endcaps are not perfectly spherical, they flatten out quite markedly. Don't know how you would calculate that - my maths is certainly not up to it!

[coreylan]

Well, if they're just domes with the tops cut off that would be easy enough to account for. Ellipsoids instead of spheres would be somewhat more difficult but still doable. I would imagine a general formula would be quite valuable for Gordon so he wouldn't be flying blind if he wanted to create a blob 55 later on or something. If he wants a formula for a blob with a flat spot on the bottom I can work one out for that too.

[bigmatt]

I would like one!

[Paul Savage]

55lb blob is already available from heavy grip tools, as well as a 66lb blob (30k), they cost a euro per lb - am i missing something here??

if anybody from the uk wants to get these click the link in my sig - split the cost of shipping between a bunch of people an it's not so bad

[DAN PRAYDIS]

lets hope they fit in a $9.00 flat rate box

[vikingsrule92]

55lb blob is already available from heavy grip tools, as well as a 66lb blob (30k), they cost a euro per lb - am i missing something here??

if anybody from the uk wants to get these click the link in my sig - split the cost of shipping between a bunch of people an it's not so bad

Yeah but it costs about a minumum of ~$250 to get anything from there shipped to the US, plus this would be built more to york blobs likeness, not sure how the HGs are shaped and all of that.

[ae_yogi]

I would like one as well, assuming that they are not super expensive.

[bigmatt]

Any word yet?

[pexter]

Man!!! I want one too!! When will these be made available?I want one to go along with my BLOB50.

[GordonV]

Sorry Guys I should have been more diligent with the updates.

The foundry is doing a run of BLOB50s and I should have them sometime around the 18th of this month.

My brother is supposed to be doing the 3D CAD drawings of the DWBLOB and the BLOB60 so I can confirm the weight and give them to the foundry for prototyping. Due to work and studying for the professional engineering exam he has been unable to get the drawings done. He takes the test next week and has promised to get the drawings to me as soon as possible after his test.

I'm a little frustrated because this is taking longer than I had hoped but they should be ready to go this summer. Hopefully I am able to post about progress shortly rather than just posting to say that little has changed.

Thanks!