Limb design philosophy and ideas

[Kirkll]

I've always done my tapping by hand. felt i had more control over it. Never tried it in the drill press/mill. i was always afraid of stripping out the threads i just cut. Do you guys turn the chuck by hand doing this?    Kirk

[Mad Max]

I've always done my tapping by hand. felt i had more control over it. Never tried it in the drill press/mill. i was always afraid of stripping out the threads i just cut. Do you guys turn the chuck by hand doing this?    Kirk

We are talking about tapping by hand Kirk, look at the top end of a tap, it has a center hole in it, use like a center punch in the chuck, pull it down into the center hole of the tap to hold it square and turn the tap with a tap handle.

[Flem]

I use my drill press for tapping all the time. Works great, just don't turn it on
Also helps to disconnect the belt or drive system, easier to turn the chuck by hand without the tension.

[Appalachian Hillbilly]

This divot. Just leave the work in position, raise the chuck high enough to get the tap in and lower the bit down gently into that divot and just use it to keep centered.

Technically you would swap out the drill bit for a live center.

[Kirkll]

Well turning my mill by hand to tap a hole is going to be rough to do just gripping the chuck. I can easily do it with a T-handle.....  Sorry.... This doesn't make sense to me guys... I mean... I don't do that much tapping, and rarely have any problems. I just start the tap, eyeball it for square, and do the deed.

Maybe i'm just dense, but i still don't see what the divot or hole in butt end of the tap has anything to do with this procedure.   

[Crooked Stic]

If your chuck  is big enough go ahead and put the T handle in there then you got to turn it with. For me I have a block that is threaded straight to guide the tap. My eyeballs ain't that good.

[Appalachian Hillbilly]

Tap guide. They even make some that are spring loaded. On larger taps with coarse threads, they are awesome.

[Kirkll]

OK.... thanks for the photo. I get it now.  Kirk

[Appalachian Hillbilly]

Keeping limb stuff in the same thread.

I chronod my new set of limbs for my 3 piece. 42 lb draw at 28 and with a 418 grain arrow and B55 string I got 160 fps.

What can be achieved with long bow speeds? Is there another 10 fps on the table somewhere or maybe just another 5  without going up in poundage and going to recurve?

Thoughts?

[Shredd]

With a Fast Flight string you can gain 3 to 4 more fps I am guessing ( it has been so long since I have messed with B55)...

  A good average high speed is 180 to 184 fps for R/D bows and 184 to 188fps for recurves...  All at 10 gpp...  You can go higher if you work at it and refine your design...

[Appalachian Hillbilly]

Thanks for the reply, sounds like I got some experimenting to do!

[Kirkll]

There are a lot of bows out there that shoot 160-170 FPS at 10 gpp @ 28".... So it's not bad.... But like Shredd stated, with some tweaking , you can increase your performance significantly. I have some designs that shoot better at 30" draw than 28" with the same gpp . These have shorter limb travel than most bows.    Kirk

[Sant-Ravenhill]

Super thread! TTT

[Kirkll]

Keeping limb stuff in the same thread.

I chronod my new set of limbs for my 3 piece. 42 lb draw at 28 and with a 418 grain arrow and B55 string I got 160 fps.

What can be achieved with long bow speeds? Is there another 10 fps on the table somewhere or maybe just another 5  without going up in poundage and going to recurve?

Thoughts?

One more thought for you bro.... Go to a fast flight string like BCY -X  or Mercury, or even D-97 is better than B-55.  The string type will add to your performance.

Another thing to do on a new design is change the string length and brace height. Typically a lower brace will give you better performance. If its a 3 piece, try shimming your limbs at the end of the riser slightly and  that can increase preload.... 

The best bet is to have an adjustable riser to change your limb pad angles and adjust the pre load. then find the sweet spot that limb is bent at brace, and measure back from the string about 7" to 7.25 to the deepest part of your grip..... 

I'll share a little secret here.... If your string is only 2.5"-2.75"  shorter than you bow length, and it's preload is 2X the draw weight on the string using an in line scale.... You are going to start seeing some excellent performance increases.... Food for thought.     Kirk

[Mad Max]

Keeping limb stuff in the same thread.

I chronod my new set of limbs for my 3 piece. 42 lb draw at 28 and with a 418 grain arrow and B55 string I got 160 fps.

What can be achieved with long bow speeds? Is there another 10 fps on the table somewhere or maybe just another 5  without going up in poundage and going to recurve?

Thoughts?

I hear if you collect old bows, 50's, 60's,70's bows you need to use a B55 type string, I don't know exactly why ?
Maybe to keep the shock down on the limbs ?
I use Horn, Sheep/Buffalo on all my NEW bows and a D97 type string. You can use wood lams under and on top of the horn but your string groove needs to be down into the horn.

What other types will hold up to a D97 type of string? I would think Phenolic
I was told you can't use layers of glass?

[Crooked Stic]

My overlays for tips usually 2 .040 glass and matching wood on top. The string lays on the glass. D97
When  I first started building never used any glass or phenolic. Two layers of most times Osage with FF string. Only can remember one failure.

[Mad Max]

My overlays for tips usually 2 .040 glass and matching wood on top. The string lays on the glass. D97
When  I first started building never used any glass or phenolic. Two layers of most times Osage with FF string. Only can remember one failure.

Some Osage Selfbow guy's use D97 but they twist short B50 strands in the loop to keep from cutting the Osage.

[Appalachian Hillbilly]

Kirk, so you are saying to measure how much tension the string is at while at brace height? Not how much it takes to pull on the string .

Never thought of looking into that aspect!

[Mad Max]

Kirk, so you are saying to measure how much tension the string is at while at brace height? Not how much it takes to pull on the string .

Never thought of looking into that aspect!

Yes at brace

[Appalachian Hillbilly]

I will have to try that! I almost have the last vehicle left in my shop done, then it is converted full time to my bow making hobby.

I almost have my adjustable riser plans complete. Will be used for testing and even for a shooting machine. Will be able to do 15-19 inch riser designs with adjustable limb pad angles and a bolt on adjustable shelf . The shelf will be adjustable for venter shot and for different brace heights, reflex deflex etc.

Can be mounted on the wall for tillering or on a bench for speed testing and draw stacking stuff.

Working on the shelf design right now.

Can't wait  to play with it.