Aaron Murray
07-18-2023, 4:49 PM
After appealing to the manufacturer of this saw I have hit a brick wall. So I ask you lovely folks here:
I have a Wadkin resaw and am having some trouble getting proper tension established on the blade. I to recently replace a badly worn ‘saw tension screw’ as well as the Belleville washers used as the tension spring. When disassembling the unit, I took photos of the damaged part and the orientation and quantity of the Belleville washers installed around that shaft so that I would be putting things back correctly. The 1/2" diameter steel shaft itself was tapered within the core of the washer stack and I was told this was not per design and due to 'wear'. All of the documentation I can find pertinent to this saw shows a stack of 18 washers in series. Any copies of the manual for the saw are such poor quality that the stack cannot be discerned including the prinetd one we got with the saw when purchased. The similar C8 saw manual has much better photos and the “top slide assembly” page looks to be identical to our parts. The stack I am referring to is listed as “K12” in that manual from DaltonsWadkin.com.
I have an engineering question about that stack. According to the Belleville manufacturer, the installation is a series stack and follows these rules:
“Single disc springs are assembled ‘opposed to each other’ to form a spring column. This ‘in series’ formation (no.3 in above illustration) is a means of multiplying the deflection of a single disc spring, the force element remains as that for a single spring.”
https://www.bellevillesprings.com/stacking-disc-springs/
The part number for the washers in the manual are noted as part number “04020415” and after searching Belleville’s website for a matching part via measurements I found the following washer and am taking engineering data from it:
https://www.bellevillesprings.com/products/d4020415/
At 90% deflection the washer in question will provide 2974 N of spring force (668.58 pounds). That means that the full stack is only returning a little more than 700 pounds of force when fully compressed. Our blades are 2” Lenox with a cross section of .06745 sq in and to generate the minimum tension (25,000 psi) on the blade the stack would need to be returning over 3,300 pounds of force to the upper wheel (1686 pounds to the blade times 2).
The stack of washers is obviously meant not to bottom out since the tension pointer on the saw is using the distance the stack compresses to generate a reading. Is there a configuration of the washer stack that I should be utilizing instead of the one in the manual? Have I missed an important piece of this puzzle?
Thanks.
I have a Wadkin resaw and am having some trouble getting proper tension established on the blade. I to recently replace a badly worn ‘saw tension screw’ as well as the Belleville washers used as the tension spring. When disassembling the unit, I took photos of the damaged part and the orientation and quantity of the Belleville washers installed around that shaft so that I would be putting things back correctly. The 1/2" diameter steel shaft itself was tapered within the core of the washer stack and I was told this was not per design and due to 'wear'. All of the documentation I can find pertinent to this saw shows a stack of 18 washers in series. Any copies of the manual for the saw are such poor quality that the stack cannot be discerned including the prinetd one we got with the saw when purchased. The similar C8 saw manual has much better photos and the “top slide assembly” page looks to be identical to our parts. The stack I am referring to is listed as “K12” in that manual from DaltonsWadkin.com.
I have an engineering question about that stack. According to the Belleville manufacturer, the installation is a series stack and follows these rules:
“Single disc springs are assembled ‘opposed to each other’ to form a spring column. This ‘in series’ formation (no.3 in above illustration) is a means of multiplying the deflection of a single disc spring, the force element remains as that for a single spring.”
https://www.bellevillesprings.com/stacking-disc-springs/
The part number for the washers in the manual are noted as part number “04020415” and after searching Belleville’s website for a matching part via measurements I found the following washer and am taking engineering data from it:
https://www.bellevillesprings.com/products/d4020415/
At 90% deflection the washer in question will provide 2974 N of spring force (668.58 pounds). That means that the full stack is only returning a little more than 700 pounds of force when fully compressed. Our blades are 2” Lenox with a cross section of .06745 sq in and to generate the minimum tension (25,000 psi) on the blade the stack would need to be returning over 3,300 pounds of force to the upper wheel (1686 pounds to the blade times 2).
The stack of washers is obviously meant not to bottom out since the tension pointer on the saw is using the distance the stack compresses to generate a reading. Is there a configuration of the washer stack that I should be utilizing instead of the one in the manual? Have I missed an important piece of this puzzle?
Thanks.