Female plate for Tiffen lower dovetail

[Jerry Holway]

Thomas -

 

Yes, that's what I call it (and that's what the part is called for Antlers, anyway). I don't know anyone else's "official" name for the part.

 

There is available now for Tiffen a 3rd battery module that attaches to (grabs!) the smaller (Archer/Zephyr) dovetail. The larger doevtail version of this battery holder should be available soon, I'm told (but not by CineGear).

 

Regardless, call Mike Craigs or Dan Ikeda at Tiffen direct, or Peter Abraham on the east coast, or Robin Thwaites/James Elias in the UK for details - it's not up on the website yet; I just checked.

 

Mark-

 

yes, use the 1/4-20 threaded hole in the bottom of your sled. Just the ticket and much less expensive.

 

Jerry

[Richard James Lewis]

I think the Marell dovetail bracket mentioned is for sliding on the old master series base, and I don't believe that's the same width as camera plates?

 

Throwing it out there.

 

Rick.

[Mark Schlicher]

I've had conversations with Peter about the battery holder, here's what I know.

 

For the Zephyr it adds a second battery holder, with the purposes of providing more 12v runtime, hotswap and adding the promised 24v capability. I want to be careful to note that I have only confirmed that it will provide 24v capability, but I can't imagine that Tiffen would have not provided the other capabilities.

 

A prototype was shown at NAB. It is aluminum and grabs onto the bottom dovetail, essentially putting the battery under the post. Not super lightweight but as Peter pointed out to me, you are going to use this item for heavier cameras anyway. Don't know if it can slide back and forth. I've not seen a picture. Anybody snap one?

 

I hadn't heard if they are for sale yet.

[Jess Haas SOC]

I can't reveal Tiffen's true dimensions and tolerances for the dovetail, but it doesn't matter in this case as it is not a critical dimension for a screw in type dovetail grabber like Steve Fracol or the Antlers uses.

This attitude is exactly why I have zero desire to buy tiffen products.

 

-Jess

[RonBaldwin]

When I read Jerry's comment I actually assumed that he just didn't have the part in front of him to measure. The real reason seems a bit over the top silliness. Last year I needed to do some mods to my pro sled and George paddock emailed the schematics with all critical dimensions to my machinist to save time, effort and money by not having to reverse engineer parts/plates. Greg Bubb would do the same. I am not saying that because one does it so should the rest -- but in our small community sharing little bits like this is the way it is. It's why we have this forum.

 

It seems a bit like GM not releasing the size of their rim because one might buy an aftermarket tire.

[Louis Puli SOC]

I can't reveal Tiffen's true dimensions and tolerances for the dovetail, but it doesn't matter in this case as it is not a critical dimension for a screw in type dovetail grabber like Steve Fracol or the Antlers uses.

This attitude is exactly why I have zero desire to buy tiffen products.

 

-Jess

 

Ha Jess

Give Jerry a brake .

If he has signed some type of confidentiality agreement with Tiffen so be it . If I needed that information I would contact Tiffen direct .If I was a customer I would expect an answer and I know they would get me one.

In these times where patens are not worth the paper they are written on Tiffen like many others manufactures will not give all of there hard work ,designs ,etc for all to see and Rip Off. eg Ebay under steadicam,Ripoff city.

just my 2 cents

Louis

[Eric Fletcher S.O.C.]

 

Eric-

 

Alas, I can't reveal exact dimensions AND tolerances.

 

As part of my deal with Tiffen, I can't reveal that stuff, nor can I choose which dimensions AND tolerances to reveal or not... no matter what you or I might think of this practice in this particular instance.

 

 

 

Jerry, your post comes across as a five year old that tells every other 5 year old on the playground that he has a secret but he can't tell you. In the future if you don't want people to point out that you're acting like a five year old, refrain from posting unless you are going to post the answer.

 

It's a dovetail as such it's tolerances can be in excess of +/-.05 and still clamp tight.

 

It's amazing how XCS and PRO-GPI will bend over backwards to help customers and potential customers and yet you choose this way to represent tiffen...

[Jerry Holway]

Eric,

 

I'll point out (again) that I told Mark how to measure a dovetail plate - not by putting calipers across the width, which has been rounded off and can't be relied upon for setting the width of the dovetail faces relative to the bottom surface, which is the real dimension one needs in this instance. I also said that for his purposes it was not a critical dimension. Easy to measure and not a big deal; certainly not a big secret that I'm holding, nor am I withholding information that prevents anyone from making a dovetail grabber. In fact I'm insuring that anyone can properly measure any dovetail and then make a dovetail grabber that works for any dovetail that they might own. Or make a dovetail that will probably work.

 

The dimensions for the dovetail itself is more critical for Tiffen stages due to the clamping lever... again, irrelevant to Mark's inquiry.

 

Tiffen can release anything they want to their customers (and have done so in the past), I just can't do it in their name, and so I did what I could.

 

Jerry

[Mark Schlicher]

Thanks, Jerry for going out of your way to help as much as you can, given the constraints of your legal agreements with Tiffen.

 

I don't fully agree with Tiffen's approach to protecting their R&D investment and intellectual property, but I understand and respect why they do it. I also get that, as a licensor and contracted developer, Jerry's not in control of Tiffen's marketing or manufacturing decisions.

 

I have had my frustrations in dealing with Tiffen. Sometimes significant annoyances. But never from folks like Jerry, Garrett or Peter, who have been unfailingly helpful and who walk the walk when it comes to passion, vision, and generosity. I've benefited immensely and directly from them in my brief history as an operator.

 

I appreciate Tiffen for risking what I am sure is considerable capital, to bring to market innovative tools for various price points and market niches, including but not exclusively the big rig market. Thank you for providing choices.

[Jess Haas SOC]

Give Jerry a brake .

If he has signed some type of confidentiality agreement with Tiffen so be it

i have nothing against Jerry and have no expectations of him violating his NDA. Its just that his statement seems to perfectly illustrate why I choose to not buy Tiffen products. The non modular nature, refusal to sell individual parts and general proprietary nature of their business model just doesnt really fit with the way I like to do business. They have every right to do business the way they do, I just prefer a more open model.

 

-Jess

[Thomas English]

I appreciate how fun it is to slag off business and IP practices, but that is going off topic to continue that on this thread any further than the comments already made.

 

So Richard Lewis is right. The Marell dovetail grabber is only for tiny 32mm dovetails found at the bottom of a master sled. We are left with the Catgriller, a Tiffen battery unit and one that Brant Fagan may sell.

 

I tried checking out the GPI Pro option.. modifying the Gyro dovetail grabber but my research stopped short at their dovetail grabber costing around $600. I am sure its very nice but I don't want to spend that much.

 

Has anyone called Brant Fagan yet and found out for sure he'd sell you one and if so how much?

[Jerry Holway]

Here is how to measure a dovetail - use two known diameter rods and a flat surface.

 

Don't be alarmed, the image is not cut off to protect anything; it was just the clearest image of how to do it.

 

The key is to have a known width at a known height from the flat clamping surface. The rods allow you to do this.

 

In this case I used two .1865 diameter rods (.001 shy of 3/16, it's what I had around to work with). The reading is improved if on holds down the rods on the flat surface, but it does not photograph so well with my hands in there. The reading I got was 1.6595 when I held the rods down.

 

Alas, I do not have a Zephyr sized dovetail to measure, but I have the adapter, and it is .6005 wide; ie. the smaller dovetail is about .600 less wide than the larger one.

 

It's better to generate these numbers with a precision standard (.2500, .1875) but this will work and it's plenty accurate for a dovetail grabber.

 

Jerry

[Thomas English]

Thanks for that Jerry. Sorry if this is a stupid question but I find it really interesting the practical techniques used to measure stuff in machining.

 

So do you just subtract 2x the diameter of the rods from your reading and then use the measurement at the top and the measurement at the bottom to calculate the gradient. Although are these two measurements ruined by whatever chamfer has been used (top/bottom).

 

Also do we know that the rods are contacting at a horizontal tangent? Is this important. If this is an assumption then it gives us the width at a certain height without the "dovetail" gradient. Or is there already an assumption about this gradient I don't know? 45 degrees on the nose maybe?

[RonBaldwin]

I forgot panavision made a small one at one time to mount a panatape to the low mode plate, I use it sometimes but it is pretty thin and dainty! The one pro makes is expensive but very nice, it is basically the top part of a dbox2. I hacked up my old cp model2 top stage and made one. I'd like a sexier one though.

[Jerry Holway]

Thomas -

 

The angle of the dovetail surfaces is specified, usually 45 or 60 degrees; in our case it's 60 degrees. Theoretically, one can specify the bottom width and the angle, and how high the dovetail is, and this will generate the dovetail profile.

 

The problem comes in measuring this shape, because the width at the bottom would be a knife point, and this is rounded off, so there is nothing left to measure. (As I said to Mark, measuring this width is close enough to say it's a big or small dovetail, but not to make one or a proper grabber).

 

Using two rods of known diameters will contact the dovetail at a given height (1/2 the diameter) from the bottom surface. Subtract the two rod diameters, and this number will generate the exact profile of a dovetail. Any diameter rod that contacts the sloped surface will work, but one usually chooses a known standard to make the calculations and measurements easier.

 

Machinists will then use this information to choose a dovetail cutter of the proper angle and set up their machines to produce this profile (there are many ways to skin this cat).

 

For testing the profile, to be sure it was machined accurately, one again uses the two rods.

 

To design a dovetail using a CAD program, one lays out the trapezoidal shape (angle and height) and the two rod diameters tangent to the bottom surface and one to each of the slopes. One can then specify the width as center to center on the rods, or edge to edge on the rods as we measure it, or the bottom knife edge width. If you specify the bottom width, the program will show you what the measurement will be with the rod size you are using.

 

The "female" dovetail is specified and measured in much the same way, but the rods are on the inside of the shape, again contacting the bottom surface and the slopes.

 

Jerry