Stamper diameter?
Moderators: piaptk, tragwag, Steve E., Aussie0zborn
Stamper diameter?
Can anyone tell me the exact diameter of 7" stampers preformed to alpha toolex machines? I'm machining platens for a home built record press and I can't seem to find info anywhere. Also, is there a "non-stick" solution I need to apply to the stampers before use?
Re: Stamper diameter?
Well The question is really an easy one my friend You need about 1/2"-3/4" extra around the perimeter
In other words an extra 1"-1.1/2" in diameter past the triming point of the record
But I am not so sure why the question as it is a case of the type of mold you use, one preforms the stampers to suit the mold
Generaly The stampers are centered and punched where they are to be held in the centre on to the mold
Than a 30-40 Degree angle is formed at the perimeter the rest takes its shape of the mold like the profile after the first pressing
So it is a case of the mold as well as the way the stamper is held in there as to what the angle is
In some presses where the stampers are glued on they are left almost flat in others they are preformed with a slight ridge as well as a flat area where the holding ring fits over so as to hold it down, never frimly either as they need to be free to move due to expansion contraction through the cycle
So it is a case of the molds as well as the means of holding them down that determines the preforming
In the Alpha autos there are many variations of the stamper holders as you can thing of, as well as the Leneds, depending who owned them prior
Just about any one out there has they own method as well as diferent angles at the edge of the mold
So there is no such thing as standard, if that is what you are asking I am afraid it would be a long shot
Suffice to say that a TTT punching and forming hydraulic press was used extensivelly in the continent and as it was a good system, so most european plants complied with its design criteria so as to take advantage of the fact that it lessened two operations as it formed the center punched the perimeter and preformed the stamper, normally separate operations
But in the UK the stampers punched and formed with them where 1/8" to short for the Alpha molds produced there for years due to a diferent angle present on the mold
No simple answer to this Sam, so look at your molds, than the way you are to hold the stampoer down than it is an easy task
Cheers
In other words an extra 1"-1.1/2" in diameter past the triming point of the record
But I am not so sure why the question as it is a case of the type of mold you use, one preforms the stampers to suit the mold
Generaly The stampers are centered and punched where they are to be held in the centre on to the mold
Than a 30-40 Degree angle is formed at the perimeter the rest takes its shape of the mold like the profile after the first pressing
So it is a case of the mold as well as the way the stamper is held in there as to what the angle is
In some presses where the stampers are glued on they are left almost flat in others they are preformed with a slight ridge as well as a flat area where the holding ring fits over so as to hold it down, never frimly either as they need to be free to move due to expansion contraction through the cycle
So it is a case of the molds as well as the means of holding them down that determines the preforming
In the Alpha autos there are many variations of the stamper holders as you can thing of, as well as the Leneds, depending who owned them prior
Just about any one out there has they own method as well as diferent angles at the edge of the mold
So there is no such thing as standard, if that is what you are asking I am afraid it would be a long shot
Suffice to say that a TTT punching and forming hydraulic press was used extensivelly in the continent and as it was a good system, so most european plants complied with its design criteria so as to take advantage of the fact that it lessened two operations as it formed the center punched the perimeter and preformed the stamper, normally separate operations
But in the UK the stampers punched and formed with them where 1/8" to short for the Alpha molds produced there for years due to a diferent angle present on the mold
No simple answer to this Sam, so look at your molds, than the way you are to hold the stampoer down than it is an easy task
Cheers
Chris
Re: Stamper diameter?
Hey thanks so much, very informative. I'm building a press based on the Emory cook method, the only reason I ask is because the test stampers I should be getting soon are preformed to an alpha press. I guess I'll just have to wait till I have them in hand to machine platens. Thanks again!