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I am designing a new Fox style bender for my shop with easily interchangeable waist and cutaway cauls. I was in the process of picking out the extension springs to use and realized I do not know the max load rating needed. I do know the inside hook dimension both contracted and max stretch needed but not the load rating I need. This is part of the equation needed to size the spring. I was thinking I want about 20#

Does anyone off the top of their heads know what load rating the large lower bout spring is on most fox benders? I want to go to a different closed length but want to keep the max load a full stretch the same as what I have now

Knock knock John Hall. I know you can answer this.

By the way I will make these plans available as soon as I proof out the design, but only in electronic format (PDF and DWF) only!!! The plans will include custom fitted waist and cutaway cauls for OLF SJ, OM and MJ as well as Martin D type body as well as plans for Standard and cutaway bending forms to work with this new bender or alteration needed to adapt commercially available forms.

foot note: This machine is designed for use with a blanket. It could be adapted to bulbs with some alteration but is not suitable as it will be drawn.

never mind I got it

Michael, I hope you can post some pics soon. I am in the process of building my fox bender according to the LMI plan. Rich

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Rich Smith
Issaquah, WA

i don't need pictures I just need the LBS/in rating of the spring they use. It should be on the material list

He's asking if you will post pictures when you're done building your new bender MP.

So what is the load rating for those springs (my guess is they are the same for the upper bout)? 20# sounds like it would be alot more than you'd need especially since there are two springs to pull in the bout.

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Talking on the phone a reading at the same time is dangerous. I did miss read. I will post a picture as soon as the plans are complete and then again when I finish the build.

Well as it turns out you are right by a lot. 47/64 dia .092" wire 8" coil hook end is just 5.11 lbs/in this is based off what my old machine came with I would like a bit more than that. I am going to set it up on a pin locked cam lever so that once the bend is made it will be easy to disengage with out having to move the pull caul back up the lower bout to remove the spring.

I can tell you that I just used a spring from Ace Hardware for my bender and it was a 9/16" X 6" X .072" made by Century Spring Corp. #C-231 seems to work OK.

That rates a bit lower at 4.45 lbs/in but pretty darn close

part of my issue is to cover my entire product line lower bout range with just one spring pivot location (one of my goals of my the new machine) I need 8" spring

I read something about a new design of a Fox bender. Is your new one of the new design what ever it is or are you just customizing the bender to a design for your needs? Also have you given any thoughts to putting parallel springs on for more tension or is that not an obtion? Or maybe putting a turnbuckle in line with the spring to adjust the tension?

The new Fox bender prototype at the GAL Convention had an open tower design. One side was open so that the guitar forms could be easily changed or the bent side could be removed easily without removing the form.

Cal

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