Manfrotto 454 focus slide: dial & Allen key modification

dunksargent · Post by **dunksargent** » Sat Oct 15, 2011 7:00 pm

This illustrates a dial addition for the Manfrotto 454 focus slide and Allen key use to enable accurate dial movement. The dial has been calibrated in 20 micron steps ie there are a total of 50 dial segments per 1mm travel of the focus slide screw . This should be sufficient for making eg 100 steps over 2mm travel of the focus slide ... or 200 steps over 4mm. The dial is a friction fit over the thumb screw and thus moves with it rather than being attached to the focus slide plate. The centre of the dial has been shimmed with additional layers of card to provide more grip/purchase against the thumb screw. The white Tippex mark on the focusing slide plate serves as the pointer ... and coincidentally the thickness of the focus slide plate corresponds with the dial segment width.

The thicker lines on the dial at 90˚, 180˚, 270˚, and 360˚are really superfluous but were required for the initial marking out into quadrants when I originally planned to draw 10 micron divisions. These were difficult to mark out with dividers so I decided on 'easier to calibrate' 20 micron divisions instead ... ie 50 segments per 360˚instead of 100 segments . To mark out the 50 segments I used screw set dividers and by trial and error adjusted them until they covered exactly 25 divisions around the circumference over 180˚. A much larger dial was constructed initially as it enabled easier calibration using the dividers. Once the radii were drawn the dial diameter was reduced. The Allen key enables much easier and more accurate turning of the thumb screw .

As an aid to smoother slide travel, the 1mm pitch slide screw has been very lightly oiled.

The brass friction screw has a compression spring in the forward end which pushes onto a 'stop' which rubs against the slide screw.

The brass friction screw requires precise adjustment to ensure reasonably free, but not too loose, focus screw travel.

The next stage is to try some photo stacking with the gadget but I also plan to make an additional neater dial - possibly with provision for a small Velcro tab to hold it more securely on the thumb screw. An additional dial will enable both X and Y movements when two focus slides are used in tandem. Once the dial is perfected it can be photocopied. The above dial was made using thin but centrally reinforced card; I may try using plastic food carton material next time as it will be more resistant to crushing.

Unfortunately in the UK we do not have many opportunities to purchase micrometer stages/ linear stages - hence this experiment to modify the focusing slide for stacking use.

Best wishes

dunk

SONYNUT · Post by **SONYNUT** » Sat Oct 15, 2011 8:20 pm

no ebay in uk?

elf · Post by **elf** » Sun Oct 16, 2011 12:38 am

20 microns will get you to 5X, 10 microns should be doable. Here's a dial face that is divided into 100 steps instead of 50.

If you added a vernier scale, you could get even finer steps.

Harold Gough · Post by **Harold Gough** » Sun Oct 16, 2011 1:02 am

For those who do not have a Manfrotto 454 it is worth pointing out that, from your illustration, you are using two clamped together to give movement in two directions at right angles.

Harold

dunksargent · Post by **dunksargent** » Sun Oct 16, 2011 2:08 am

SONYNUT wrote:no ebay in uk?

I often see micrometer stages on Ebay but they are offered by overseas sellers. The cost of the overseas shipping to the UK plus HM Revenue and Customs i) Duty and ii) VAT plus the shipping agent's collection fee has to be factored in - this can make the final cost of an item very expensive.

I've only seen one linear stage offered on Ebay UK in the last month but my bid was unsuccessful.

The dial modification might help anyone who already has the Manfrotto 454 but who has not yet acquired a micrometer stage to try some stacking.

dunk

dunksargent · Post by **dunksargent** » Sun Oct 16, 2011 2:21 am

elf wrote:20 microns will get you to 5X, 10 microns should be doable. Here's a dial face that is divided into 100 steps instead of 50.

If you added a vernier scale, you could get even finer steps.

Thanks very much - I'll try it. I originally wanted to use 10 micron steps but my rather crude tools would not permit accurate drawing. Adding a vernier as well might be a bit of an overkill because of the focusing slide's relatively large 1mm pitch.

Best wishes

dunk

ChrisR · Post by **ChrisR** » Sun Oct 16, 2011 5:06 am

Well done Dunk, I think the 454 is more useful than some give it credit for. It really isn't sometihng a precision engineer would be proud of, but hey it works, and fixes straight on to a tripod and camer for the same cost as a couple of arca-parts. If you do the clamp screw up the camera moves, and it's rather odd to me, to be clamping directly onto the thread itself. The camera also takes a sidways lurch if you change direction.

I also use a hex key with it, as first suggested I believe by Laurie. I used one when travelling, clamped to an upturned table's leg, or the side of a wooden drawer.

I thought my 454 was 1.2mm pitch, not that it matters too much.
Thanks for the disc elf, could you do one for 60/120 divisions?!
Actually the lines should be offset a bit, because the level where the tipp-ex is applied, isn't radial to the leadscrew but on a tangent about 5mm above it. I'd measure it, but I can't find mine. It's probably in the fridge with my car keys.
Errm, two lines shown...

The assembly of the leadscrew is , um, cheap. The hex socket screw (blue)you can see , where the hex wrench goes, is effectively a locking screw which sets the friction against the ends of the slide. Nothing fancy like a spring-washer in there! But it does mean that if you use two or three washers instead of one (green) you can clamp the calibrated disc (red). I thought it might need a locknut to stop it slipping but it seems to be OK.
A domed-variety spring washer we used to call "belleville" type would be good in there.

I did something in Photoshop but the numbers were too much trouble:

Those divisions make sense to me, but I know my brain is at times only marginally compatible with intelligent life forms.

Ebay from the UK can be a real pain. Shipping and taxes on something simple like an arca-clone rail can easily come to more than the product itself, then some sellers have learned not to ship anything beyond the lower 48 states.
I am currently accumulating some parts with a kind volunteer in the US who I hope will enjoy playing with some of them. I shall not name him here for fear of abuse!
Recent example, a Nikon K1 ring. US price $4. Shipping to UK $22. Customs see $26 and add £13 ($20) inspection fee, then 20%, a total $50 overhead.

dunksargent · Post by **dunksargent** » Sun Oct 16, 2011 5:30 am

Thanks Chris; I have not measured the 454's pitch accurately - I just assumed it was 1mm because one revolution of the thumbscrew moves the slide approx. 1mm. I expect you are correct in stating that it is 1.2mm. Yes the whole contraption is crudely made and I know of some photographers who do not enjoy using it for regular close-up photography because it can be cumbersome in use. However, if you are aware of its shortcomings it should provide a basic stacking tool.

Maybe Manfrotto have missed a a marketing opportunity in not designing/providing something similar which is a little more sophisticated and better engineered?

Best wishes

dunk

ChrisR · Post by **ChrisR** » Sun Oct 16, 2011 5:43 am

I think you're right on both counts - it "works" but could have been so much better.

elf · Post by **elf** » Sun Oct 16, 2011 12:15 pm

ChrisR wrote:
Thanks for the disc elf, could you do one for 60/120 divisions?!
Actually the lines should be offset a bit, because the level where the tipp-ex is applied, isn't radial to the leadscrew but on a tangent about 5mm above it.

Here's one with vernier scale and 120 divisions. I'm not sure what you mean by offsetting the lines.

dunk wrote: Adding a vernier as well might be a bit of an overkill because of the focusing slide's relatively large 1mm pitch.

I think it depends on how smoothly the slide moves or to put it another way, how much stick/slip it has. If it is really bad, lapping the leadscrew would help. Zerene Stacker can tell you how accurate and repeatable your steps are.

dunksargent · Post by **dunksargent** » Sun Oct 16, 2011 2:36 pm

elf wrote:
ChrisR wrote:
Thanks for the disc elf, could you do one for 60/120 divisions?!
Actually the lines should be offset a bit, because the level where the tipp-ex is applied, isn't radial to the leadscrew but on a tangent about 5mm above it.

Here's one with vernier scale and 120 divisions. I'm not sure what you mean by offsetting the lines.

dunk wrote: Adding a vernier as well might be a bit of an overkill because of the focusing slide's relatively large 1mm pitch.
I think it depends on how smoothly the slide moves or to put it another way, how much stick/slip it has. If it is really bad, lapping the leadscrew would help. Zerene Stacker can tell you how accurate and repeatable your steps are.

... Thanks very much for the 120 division dial.

I looked up lead screw lapping http://www.practicalmachinist.com/vb/ge ... ng-218177/ ... I have learnt a lot today ... not least, just why precision engineered translation stages are expensive pieces of equipment. The more i consider the Manfrotto 454 the more I realise it is really rather too 'agricultural' for precision applications. However, I'll give it a whirl and make the new dial.

Best wishes

dunk