E. Howard Strike Side Weight

sjaffe

Registered User
Dec 25, 2012
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Hello,
We've completed repairs on the E. Howard roundtop tower clock, but were not able to account for the cause of the wheel tooth damage (see my previous postings in this message board category). We are suspicious if the amount of strike train weight is incorrect. It consists of blocks which are 10.25"x10.25"x2". Assuming they are made of iron, with a density of 0.284 lbs/in3, my calculations indicate they are approximately 60 lbs each. The weight stack had 28 of these (plus the bottom plate), which would be 1680 lbs. The cable has three pulleys above, so that implies what the force would be at the clock. Is this the correct amount? If not, what should it be? Would too much weight cause teeth to bend in the 2nd arbor wheel?
Thanks,
Stan
 

gvasale

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Mar 30, 2005
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try about 500 lbs. If that works well, don't add more. If it seems to need more, add 1 weight at a time and double check. Did you ever take apart the pulleys and check them for wear? The pins do wear. Sometimes the cavity is plugged with old hardened oil and they need service or repair. I have seen at least one well known tower clock repair person overlook that.
 

Donn Haven Lathrop

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Jul 28, 2010
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"We've completed repairs on the E. Howard roundtop tower clock, but were not able to account for the cause of the wheel tooth damage (see my previous postings in this message board category). We are suspicious if the amount of strike train weight is incorrect."

I told you why the teeth failed. 1. The wheel is too weak to be used at that point in the strike train. I recommended that the new wheel be cut from hardened brass, .7 to .9 inches wide, NO SPOKES. Every one of these wheels that has failed lost teeth BETWEEN the spokes. That tell you something about the wheel and the use of spokes? 2. Count the teeth on the failed wheel and the wheel that drives it. The ratio is 2.8 to 1. That means that every 28 turns of the failed wheel it stops in the same spot. If that spot is between spokes, the wheel teeth WILL FAIL.

"[The strike weight] consists of blocks which are 10.25"x10.25"x2". Assuming they are made of iron, with a density of 0.284 lbs/in3, my calculations indicate they are approximately 60 lbs each."

For Pete's sake, take a scale up to the clock and weigh the blocks, then multiply. Don't forget the support plate and rod--weigh those, too. Cast iron doesn't always have the same density from batch to batch.

Three pulleys? That doesn't tell me how many falls of wire rope are supporting the weight. Only the number of falls actually supporting the weight will let you calculate the approximate force at the surface of the strike weight barrel. You can then use ratio and proportion to calculate the force at the rim of the wheel that failed. It's usually about 100 to 125 pounds.



"Is this the correct amount? If not, what should it be?" Without being a smartass, you need enough weight to lift the hammer. No more, no less. And it varies from clock to clock, and hammer to hammer. It's an empirical calculation with no set answer--each installation is different.

"Would too much weight cause teeth to bend in the 2nd arbor wheel?" Of course! What else did it? Too much weight, lousy wheel design, wrong material for the wheel--they all contribute.

Tower clocks: Weights, weight lines and pulleys.

Read the above and pay attention. It will help you handle tower weights, wire ropes, and whatall. No charge.

Donn Haven Lathrop
 

gvasale

NAWCC Member
Mar 30, 2005
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I would also set the fans so the strike is as leisurely as possible. Example: stopping a car over a given distance is easier when the speed is low...

likewise for the strike train of a clock.
 

gvasale

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Mar 30, 2005
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Before I forget, since bell hammers have been mentioned, they take abuse too. Way too often they get no attention and suffer heavy wear on all areas where they swing towards the bell. Many are so bad that they have to be lifted to rotate. Brackets need to be bushed and the shaft they rotate on is in need of having their pivoting ends replaced. I have even had the "handle" filled with weld where there has been severe wear where they rebound of a flat spring. Might have a photo. That will require some searching.
 

doug sinclair

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Aug 27, 2000
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I maintain a "round top" HOWARD. The strike side has a single pulley, and The striking operates nicely on 750 lbs. 375 pounds at the clock. The hammer weighs 25 pounds.
 

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