Questions re C. Schwarz's Roubo and drawbore pins

Re: Questions re C. Schwarz's Roubo and drawbore p

Christopher Schwarz

>Joel Moskowitz was just needling me about this very issue today. I have five sets of drawbore pins from England and I'm going to go over them to look for this eccentricity that both you and Joel mentioned.

I would be surprised if the set of small pins I own has that feature. I've been using those for a long time and am quite familiar with their shape. But I'll check them.

I must say that the sets I've made with drift pins work just as well as the historic ones.

As to the placement of the leg vise, that's where Roubo shows it in his plates. And it makes sense to have it there to plane into it. You actually don't need both the leg vise and crochet, but they are so inexpensive and easy to make I recommend you try both. Then keep the one you like best.

Chris

Re: Questions re C. Schwarz's Roubo and drawbore p

Pam Niedermayer - Austin, TX

>Thanks, Chris.

Since Joel told me about the eccentricity, you can count this as a single comment. :)

On the vises, I see very different uses for the crochet and leg. Granted, both will hold a board for planing on edge; but the screw would limit the board size more than the crochet. Also, I doubt that the crochet can handle chair clamping like the leg vise.

Pam

Re: Questions re C. Schwarz's Roubo and drawbore p

Joel

>I'm going to try to scan my drawbore pins tonight to show what I am talking about. (I'm not making this up)

Re: Questions re C. Schwarz's Roubo and drawbore p

Pam Niedermayer - Austin, TX

>Sorry, Joel, I wasn't questioning your statement. I verified the eccentricity to my satisfaction when I got my largish drawbores from Tony Murland.

Pam

Re: Questions re C. Schwarz's Roubo and drawbore p

Christopher Schwarz

>Actually, the leg vise can handle an entryway door on edge. There's a lot of clamping area in front of the single screw. Roubo actually was an advocate of the leg vise and couldn't understand why other craftsmen stuck with the crochet.

As to the drawbore pins, my small-size set are not eccentric. I checked this morning. I'm going to post pictures on my blog this afternoon. The other pins are on loan to various people and I'm checking with them now.

Chris

Re: Blog addy? Thanks :>)!!

Frank Mutchler in Colorado Springs

>

Re: Blog addy? Thanks :>)!! *LINK*

Bob Lang

>Here it is:

http://www.woodworking-magazine.com/blog/


Woodworking Magazine Blog

Re: Questions re C. Schwarz's Roubo and drawbore p

Joel

>Here's a photo of the top few inches of my marples drawbore pins. THe marples 1909 catalog shows them and the offset is pretty easy to see if you use a ruler for reference. the section of the steel is round, but it leans over like the tower of pisa.

I do have a question on your antique drawbore pins - how do you know that's what they originally were sold as? There is also the possiblity that there were different styles (which there most definitely were) with different advantages that are now lost - I'm not arguing that they don't work - they obviously do - but being able to get almost clamping pressure with mine seems to be an advantage and not having to force them in is really nice too. But unless of course we compare them in side by side use it's pointless to speculate.

I'm also not sure why mine are so long. all the ones I have seen are much longer than yours. I think the length might help in getting leverage in a really hard to explain way but I don't really know.

THe shortest drawbore pins listed in the marples catalog were 3/8" round by 8" long . mine are 10" long by 1/2" diamter.( not including tang and bolster)

Why are drawbore pins needed?

Tim of Livermore

>I've done some drawboring. Not boat loads but more than 10 and less than 100 drawbore mortise and tenons.

They all went together just fine without a drawbore pin. Is there something I'm missing? Other than confirming you've offset the holes between tenon and mortise, does the drawbore pin do anything else?

Tim

Re: Why are drawbore pins needed?

Joel

>drawbore pins allow you to check the fit of the joint - drawing it in real tight, very easily and quickly, without setting up clamps and without having to make, drive, and destroy wooden pins.

Re: Questions re C. Schwarz's Roubo and drawbore p

Patrick Gibbons, Houston, TX

>According to Salaman, draw bore pins are tapered, 8-12 inches long and 1/4" to 5/8" in diameter. He does not mention anything about whether they are round or eccentrically shaped.

Non-circular drawbore pins

Adam Cherubini

>Theoretically speaking:

The point at which the round drawbore pin fills one of the holes defines the end of your ability to achieve concentricity between the holes. A lobed or faceted pin can continue to be driven in, deforming one or both holes as required. Note that these local deformations have no effect on the final fit up of the joint with the trunnel. Its not like you've ruined the holes and made them no longer offset.

The elliptical drawbore pin, with its lobes oriented along the grain, reduces the potential of splitting the tenon and draws the joint together in one direction only. This may be useful in knee braces, or joints with multiple pegs.

Adam

So when will we be able to purchase some

Tim of Livermore

>from you, Joel?

The eccentric type..... :- ).

I like tools....to use, not to make. maybe when I'm closer to the end of my 1000 page list of projects to complete, I'll think about making tools : - O!

Tim