2020---->What did ya do today?

[Shredd]

what is the purpose of grounding??   dust sticking to and clogging the the works or fear of a fire or explosion as in paint booths??

[Roy from Pa]

fire or explosion

[Eric Krewson]

I have had my system in place for 20 years, one time the ground wire came loose, when I touched the hose to move things back where they were supposed to be the hair on my arm stood up from the static electricity in the pipe.

I grind bamboo on my belt sander and have a lot of fuzz in my pipe at times that I have to reach in and clear out. One spark in that stuff and my whole shop will go up in flames.

Ground your system.

[Flem]

https://www.woodworkersjournal.com/grounding-pvc/

I ground because I hate to get a nasty static shock

[Pat B]

A static spark with find wood dust is quite explosive. 

[Mad Max]

This is a piece of Osage from a 100 year old tree on my place, it's been dead for 16 years so 116 years old.
I resaw some thin lams for a riser--.030 to .070 thick, no sanding just glueup
I did the same with Bacote
The osage looks the same when you cut it, and I can't tell the difference.






This is a drawing of the tree when it was dead

[Flem]

Thats an awesome hunk of wood, art work is pretty good also
How did you mill that monster?

[Mad Max]

That block is only small part of a  5' long log, on the right side of the block (1st picture) was a long rotting crack, look at the rings.
I took that 5' to a friends saw mill and made a  few cuts.

If you ment into lams---I use a straight edge to draw a line and go to the band saw, then the edge sander.
After I get one flat edge I start cutting it up to width.

[Flem]

I was wondering if you had a mill at home, something I covet. A friend with a mill is even better!

[Roy from Pa]

Max said..    If you ment into lams---I use a straight edge to draw a line and go to the band saw, then the edge sander.
After I get one flat edge I start cutting it up to width.       

Me too Mark..

[mmattockx]

After much farting around I started final grinding of the lams for my very first lam bow. It is all wood in red oak. I'm doing a Perry reflex experiment with it where I glue the core and belly up with a bunch of deflex, then pull it forward into moderate reflex with the back lam in a second glue up.

Got the back lam down to final thickness and started working on the tapered core pieces. Should have the core and belly pieces all done by tomorrow evening if things go well, then I need to get my form done and I can start gluing stuff up.

 


Mark

[Crooked Stic]

Be interesting to know if that Perry reflex is really worth the trouble.

[Longcruise]

Be interesting to know if that Perry reflex is really worth the trouble.

I've wondered about that too.  Maybe light will be shed. 

[mmattockx]

Be interesting to know if that Perry reflex is really worth the trouble.

One bow won't be definitive, but lots of people have had success with it. Calculations say it can reduce the stresses on the belly by 15-20%, which should equal a lot of set avoided.

My goal with pulling the belly and core into deflex before pulling that assembly into moderate reflex is to gain as much stress reduction as possible on the belly while ending up with a mildly reflexed flat bow with the tips only 1.5-2" ahead of the handle. It should make for very low set, good performance and a bow that is easy to string without equipment required. If I just pulled it all into 6+" of reflex it makes for a bow that is tough to string and the back stresses get very high with all the bending required from that amount of reflex.


Mark

[Shredd]

refresh my memory... what exactly is a perry reflex...  i remember reading about it two to three years ago...  thanks...

[Crooked Stic]

https://www.tapatalk.com/groups/paleoplanet69529/perry-reflex-vs-reflex-deflex-t15163.html

[Eric Krewson]

I think the term "Perry Reflex" is a misnomer, about 25 years ago someone attached the term to any bow that had a reflexed limb and it stuck. If any of us had an osage bow that had a natural reflex we proclaimed it to have "Perry reflex", everyone used the term whether it had merit or not.

Unless you are following Dan Perry's flight bow design to the "T" you just have a reflexed bow, not a Perry Reflexed bow.

[Longcruise]

I think the term "Perry Reflex" is a misnomer, about 25 years ago someone attached the term to any bow that had a reflexed limb and it stuck. If any of us had an osage bow that had a natural reflex we proclaimed it to have "Perry reflex", everyone used the term whether it had merit or not.

Unless you are following Dan Perry's flight bow design to the "T" you just have a reflexed bow, not a Perry Reflexed bow.

True, it is described extensively in one of the TBBs.  I  think the first or second.

[mmattockx]

refresh my memory... what exactly is a perry reflex...  i remember reading about it two to three years ago...  thanks...

In very brief description the bow is built from lams (typically one belly lam and one back lam) and the belly piece is pulled forward into reflex, then the back is glued on to hold the reflexed shape. This preloads the belly surface into tension, lessening the final strain it sees when pulled to full draw.

I think the term "Perry Reflex" is a misnomer, about 25 years ago someone attached the term to any bow that had a reflexed limb and it stuck. If any of us had an osage bow that had a natural reflex we proclaimed it to have "Perry reflex", everyone used the term whether it had merit or not.

I wouldn't say it is a misnomer, but it certainly was misunderstood and the name misused to describe any reflexed bow, as you say.

Unless you are following Dan Perry's flight bow design to the "T" you just have a reflexed bow, not a Perry Reflexed bow.

You don't have to build the same bow as he did, but you do have to use the same concept of preloading the belly in tension in order for it to have the same effect (and be accurately called Perry reflex). What I am doing is the same as what Dan did, but I am adding to the effect by initially deflexing the first glue up in order to increase the preload the belly sees when it is pulled forward and glued to the back lam. I don't know if Dan ever built a bow like that, but he would certainly understand it as just a modification of his method as described in TBB V3.

I can't claim any credit for the idea of a multi stage glue up schedule to maximize the reduction of belly stresses. I got the idea from reading about the Duo-Flex bow in the Bows of the World chapter where Tim Baker talks about making a modern duo-flex using Perry reflex to increase the performance. Baker's idea (pg. 79) is to splice the belly lams in a more deflexed position than the final bow has, then pull them forward into the final shape when gluing the back lam on.

All I did was think about how to achieve that same effect in a lam bow where the limbs are not billets spliced into a deflex angle to start with. My solution is to use two forms, one for the first glue up that deflexes the belly and core lams in an arc (similar to what a bow looks like when braced), then a second reflex form to pull the belly and core assembly forward and glue the back lam on.

I will post pics of everything when it is done, but that will likely be a few weeks at the rate I am going.


Mark

[Longcruise]

Looking forward to the results.

Wonder if there would be any advantage to employing the concept in a glass bow.