4x5 diy view camera rack/pinion question

[Andreafotosg]

Hello all,
I'm reading this website since time and now I'm starting thinking to build a 4x5 view camera.
I'm looking for parts, in particular racks and pinions and I've found:

Plastic gear width 4,2 mm diameter 10 mm and hole of 2,5mm as you can see in the picture
Mod is 0,5

The rack is
Mod 0,5 length 125 mm, 4mm wide, 7 mm high as in the other picture


Do you think they could be used for a 4x5 lf camera with dimension 18x18 cm ?
Or 2,5 inner diameter of gear is too thin ?

Thanks for help
Andrew

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[Jim Jones]

For a rack and pinion made of plastic, these seem too small. If used, the 2.5mm shaft would have to be well supported. Such a small gear might wear too much. Others with actual experience with such plastic racks and pinions can provide more valid information.

[Pfsor]

Do you think they could be used for a 4x5 lf camera with dimension 18x18 cm ?

What is a 4x5 LF camera with a dimension of 7x7? The first LF camera of a zoom dimension?

[Graham Patterson]

Not unreasonable dimensions for the rear of a 4x5 with a reversible back. If it is a folding camera that also constrains the base dimensions.

[mdarnton]

I can't be sure without taking it apart, but this appears to be exactly the type of gearing driving the focus on my new Intrepid 8x10, on a close-to 2.5mm rod (with the reservation that I can't see how the track is fastened--only the teeth), with two gears and tracks, one on either side of the bed, and It's very smooth--I initially thought it might be friction drive with an O-ring until I started looking.

In the Intrepid the whole system appears to be fed through long grooves in the wood taking most of the pressure and acting as a bearing for the rod, with metal bearing surfaces only at the end, under the knobs, only needed for the lateral clamping to lock the focus..

[Jac@stafford.net]

What is a 4x5 LF camera with a dimension of 7x7? The first LF camera of a zoom dimension?

This one.

[Pfsor]

This one.

A nice example of using a rack/pinion on a camera - à la Jac@stafford.net

[Andreafotosg]

Hello,
18x18 is the dimension of the base plate

I've got another photo of the rack, but more infos can be found at:
https://www.ebay.co.uk/itm/XYCL1105-...sAAOSwcwhVO2g1

In the same shop I found also the gear

Hope it is more clear now

Andrew

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[Pfsor]

Hello,
18x18 is the dimension of the base plate
...

Thanks Andrea for your explication.
If you want my opinion on your pinion - it all depends on the construction and the weight of your front standard (plus a lens). Your rack and pinion can be all fine if the construction is precise and the weight is not overwhelming. You can put it to a test much before deciding if it is the correct size or not. You don't need to shoot into darkness.

[Pfsor]

... Your rack and pinion can be all fine if the construction is precise ...

By that I mean, to be more precise, that the racks must be strictly parallel to each other and the rod for the pinion strictly perpendicular to the racks. Which means that you cannot just screw the rack to the wood and hope it is in the good position - that would probably screw it up. You must have some means to be able to fine tune the rack position to its right position before you screw it. There are mechanical means that allow for this.