BCTW Universal Jaw Idea

Moderator: Michael

Postby rwest » Tue Jan 19, 2010 7:39 pm

Roger,

I can give you the reason for not having to add additional sections: Once you have enough length to angle your stock, any more is just aluminum flapping in the breeze! Since your stock is clamped at the jaws it can be as long as you please without anymore contact with the tool. As far as the holes on the bottom for mounting or support: I like it!

-Rutager
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Postby John » Tue Jan 19, 2010 8:27 pm

First, don't put any stock in the colors I use--they only serve to help me distinguish one part from the other.

Roger-here are your holes. The plate is under 5" in width.

Large cylinders may require custom jaws as there is a limit to the V groove in this adapter--but with this plate it would be easy to do.

What I am saying is that should the need arise, we/you can make larger V groove jaws, but I want to see some interest first--at least now this is field adaptable.

....I think this is real close! What I am concerned with is "racking" and it should not be an issue if clamping pressure is applied at the point of contact with the workpiece and then the arms are locked.

--John

Image
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Postby savatteridesigns » Wed Jan 20, 2010 1:06 am

John,

I think your ready to cast the mold!
I like the placement of the holes on the bottom.
(besides the bracing I spoke about earlier, I feel those holes will aid could also aid in the attachment of future jigs.)

Questions . . .
On the other side of the purple plate, could the screws that hold the red jaw have an extended knurled knob (for hand tightening) with a hex inset on the top of the knurled knob head for a second stage tightening?

I take it the thickness of the purple plate/jaw will be the same as the orange jaw in the original DJ-1 set?

Roger

p.s., Rutager - I follow what your saying above - also with the placement of the holes at the bottom I feel that I now have the option if needed to add something (if i need to) for further bracing of some larger or obscure workpiece.
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Postby John » Wed Jan 20, 2010 9:37 am

Roger;

I am not going to put anything on the non-business end of the plates that will protrude and interfere with putting the unit in a vice if one chooses.

In addition, hand tightening is likely to lead to slippage--and I know the cap screws will not.

Thanks for your input--I think these jaws will add immeasurably to the flexibility of the DJ-1.


--John
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Postby savatteridesigns » Wed Jan 20, 2010 10:32 am

John wrote:Roger;

I am not going to put anything on the non-business end of the plates that will protrude and interfere with putting the unit in a vice if one chooses.
In addition, hand tightening is likely to lead to slippage--and I know the cap screws will not........
--John


A most valid point, I wouldn't want it any other way.

My last two questions . . .
In order to record for later repeatable cuts did you consider some form of scale inscribed on the business side of the plates?
Or will the color of the anodizing be such that it will take pencil marks in an easy read fashion?

When do you think it will go into production?
This jig would really help to use the DJ-1 to it full potential.

cheers,
roger
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Postby John » Wed Jan 20, 2010 11:58 am

It won't do any good for us to etch reference lines OTHER than the ability to set a t-bevel, and THAT just very well may be a good idea--a built in protractor. I would have to sketch this out to see if it works. However...

My preference is to use a t-bevel set to a verifiable reference and once the jaws are in place, scribe a pencil line (they rub off) and this is the most likely scenario from my chair. It is impossible to predict the height of the stock one would use in this thing, negating fixed references other than as mentioned above.

I want to build a set first before I commit to production--I am a bit worried at the moment about racking and that concern needs to be assuaged. The final color however will be pencil friendly.

--John
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Postby rwest » Wed Jan 20, 2010 6:23 pm

John,

Thanks for asking for all of our input, I hope we gave you some headaches, it is "payback" for the CAD ones you gave me!

I truly believe that this fixture is going to simplify creative drilling in our shops, especially drilling on an angle. As well as being able to mount custom jigs.

Michael,

You'll need to clear up some space to share in your office for Roger and myself, I think we start working there on Monday!

-Rutager
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Postby 6jaw » Thu Apr 08, 2010 9:02 am

I can see a modest fault. Being symmetric wrt DJ-1, it is not possible to have a drill bushing centered wrt the supporting slots in the new fence. If the fence were wider than DJ-1 such that another slot could be added to the outside so that the outer slots were symmetric wrt one of the bushing location, some operations requiring centering of a drilled location might be made simpler.

John
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Postby John » Fri Apr 09, 2010 7:34 pm

John;

"Modest fault" is a major fault when the word "Universal" is part of the name. Makes no sense to pull punches...

I am not sure I understand your suggestion--can you post a pic or email me direct (john@bridgecitytools.com)?

Thanks in advance- this project is on hold until I "get it".

John
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Postby 6jaw » Sun Apr 11, 2010 7:40 am

I'd have to work out a way to create a picture to post, let me try to explain in words first.

In another thread, someone posted an auxiliary jig being used to drill holes perpendicular to the outside of a curved piece. I think the awkwardness lies in the bushing locations being on each side of the jig's centerline. If for example, you want to drill perpendicular to the outside of a curved piece, and the supports are symmetric with the jig, then the support furthest from the bushing location you are using must be lowered enough to align the tangent to the work at the point you are drilling to be perpendicular to the drilling axis. You can calculate this offset or you can align the piece "by eye", but it is probably approximate at best.

If the fence extended beyond the DJ on the side of the bushing location you were using, support points could be provided an equal distance to each side of the bushing centerline. Then support points "square" to the fence - an equal distance down from the top of the fence - would support a circular arc such that the axis of the drill bushing is perpendicular to the workpiece at that point. This convenience would apply only to actual circular arcs. Perhaps there's another way to conveniently align asymmetric supports to achieve perpendicular holes.

It's perhaps a small point and there are many compromises in the design of a "universal" tool. I just wanted to offer the comment for consideration.

John
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Postby rwest » Sun Apr 11, 2010 2:37 pm

Hi,

This is an excellent point. The male/female nesting button that are going to be supplied with the universal jaws should either be able to mount in slots in the mounting plates that are offset from the bushing centers by equal amounts, which would require a mounting plate that is wider then the outriggers and with 2 to 4 more vertical "V" cuts, or the longer jaws should have spots on them to mount the buttons and then a detent of some sort that fits it to the groove below the bushing so that the whole works self-centers.
-Rutager
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Postby John » Mon Apr 12, 2010 12:34 pm

John-

Got it! No picture necessary and it is solvable. I need to incubate on the concept and then I will offer up a virtual prototype for you folks to discuss.

Thanks for stopping this in time!

John
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