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  #1  
Old 09-30-2015, 08:04 AM
RockHillWill RockHillWill is offline
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Default Why use lower anvils with 'flats'?

Recent inquiries regarding the use of full radius vs anvils with 'flats' on them, has left me wanting to know why the anvils with 'flats' are used in the first place. When viewing from the end position, it would seem that the anvils with flats are more likely to leave tracks than the full radius anvils used with judicial pressure. I am just curious. What are the flat anvils used for and who got that started?

I realize this might get heated, but I am only seeking useable information.
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Old 09-30-2015, 08:17 AM
Marc Bourget Marc Bourget is offline
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My understanding, gleaned from other threads, is that the flats (with radiused transitions) distribute the forming forces over a larger area and actually reduce the ridging effects you seek to avoid.

IIRC, I believe this point was most directly addressed in a post made by Kent White.

FWIW

mjb
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Last edited by Marc Bourget; 09-30-2015 at 08:18 AM. Reason: Replaced < with a "comma" after IIRC
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Old 09-30-2015, 11:00 AM
Maxakarudy Maxakarudy is offline
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I heard that radiused anvils eventually went flat through usage, then they just decided to make them that way, could be an old wives tale.
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Old 09-30-2015, 01:06 PM
bobadame bobadame is offline
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There are 2 schools of thought, I have no idea which came first. "All the metal knows is PSI". These folks use anvils with flats and with these anvils, the technique is to bring the wheels together with enough force to squeeze the sheet metal a tiny amount. This thins the sheet along the path of the anvil flat. This thinning causes the sheet to extrude away from the contact zone and because metal is non- compressible, what it looses in thickness, it gains in area. Gravity causes the sheet to droop. Anvils with flats require the operator to track in a very precise pattern to achieve the desired 3D curve they are creating. These flat anvils must be held exactly parallel to the top wheel to prevent disaster. This leads the E-wheel frame builder down the path of stiff frame or some method of tilting the anvil to compensate for frame spread.

This method has worked well for many professionals for many years.

Then comes the true radius or full radius anvil folks. These people use a different technique to make a 3D curve in flat sheet. The wheels are brought together with much less force, (less compression). The sheet is formed by the operator physically bending the sheet over the anvil as he rolls it through. Cass calls this technique "Pumping". Imagine hand pumping water from a well. There is a downward force on the handle. With this technique the stiffness of the frame is a non issue and the tracking pattern is less critical and more intuitive.

This method has worked well for many professionals for many years.

The important thing to understand is that the technique needs to be the correct one for whichever style of anvil you use.

Or, I could be completely full of shit.
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Old 09-30-2015, 05:22 PM
RockHillWill RockHillWill is offline
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I believe everything that you say, Bob, but the recent class by Peter made me do more thinking as to which way to approach this decision. I have both 'flat' and full radius and would say that at best, I am a beginner English wheel operator, but under Peters guidance, I was actually making more 'clean' panels with the full radius dies.
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Old 09-30-2015, 06:41 PM
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Richard K Richard K is offline
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I have both styles and use both indiscriminately.

I'd say it is a "non factor" for wheeling but it' been a big deal for discussion.
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Old 09-30-2015, 06:48 PM
Peter Tommasini Peter Tommasini is offline
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Quote:
Then comes the true radius or full radius anvil folks. These people use a different technique to make a 3D curve in flat sheet. The wheels are brought together with much less force, (less compression). The sheet is formed by the operator physically bending the sheet over the anvil as he rolls it through. Cass calls this technique "Pumping". Imagine hand pumping water from a well. There is a downward force on the handle. With this technique the stiffness of the frame is a non issue and the tracking pattern is less critical and more intuitive.

This method has worked well for many professionals for many years.

The important thing to understand is that the technique needs to be the correct one for whichever style of anvil you use.

Or, I could be completely full of shit.

No Bob you are not full of shit...... you dead right !!!!!!!!!!
Peter
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Old 09-30-2015, 06:50 PM
route56wingnut route56wingnut is offline
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Peter we will be taking a visit to see Cass when you arrive for the classes .
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Old 09-30-2015, 06:54 PM
Peter Tommasini Peter Tommasini is offline
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Quote:
Originally Posted by route56wingnut View Post
Peter we will be taking a visit to see Cass when you arrive for the classes .
Looking forward to meet Cass
Peter
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Old 09-30-2015, 08:32 PM
RockHillWill RockHillWill is offline
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Just for the record, Peter has demonstrated to me that the full radius anvils are VERY capable of making smooth panels, in the same way as Cass has demonstrated, by utilizing the 'pumping' approach. I will be sending my 'flat' anvils for full radiusing this week. I was just interested in the 'history' of the 'flat' anvils.
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