Thursday, January 14, 2010

New Drive Gears Coming Soon(ish)

UPDATE (1/23/10) - My timing on these couldn't have been much better. Earlier in the week I found out that I had depleted my supplier's stock of the current drive gear. I will only have another 50 or so before there is about a 2 month wait. That is obviously too long, so when the 50 are gone we will just be going with the new, custom drive gears.

Unfortunately my timing wasn't exactly perfect. Orders up to about January 9th will ship with the original gear. Orders after that may see an additional week or so delay while the mold for the new gears is getting built and tested.

If you have an order out and don't want to (or can't) wait for the new gears, I still have some of the older 2" diameter gears available (these are the ones pictured on the web site.) Email me (dfocusinfo *AT* gmailcom) if you would like to go this rout. Remember, the new custom gears will be very easy to install, just a single set screw so you can always upgrade later.


In an effort to reduce the time it takes to build a D|Focus, I have decided to have purpose built drive gears manufactured. Let me give you an idea of what goes into just the drive gear currently:

1. I order them from a gear supplier in New York. UPS ground shipping takes about a week to deliver them
2. I have to install a brass insert so a set screw can be tightened, without the insert the threads would strip very easily.
2.a) I order brass tubing in 1 foot lengths with a 1/4" outer diameter [OD] (same as the inner diameter [ID] of the drive gears, so the brass can be pressed in) and 3/16" ID. However the tubing comes over sized, meaning the ID is a bit smaller, so it has to be reamed out to fit the 3/16" shafts. We do this on the manual lathe.
b) The brass tubing has to be cut into 0.400" lengths. The only reliable way I have found to cut brass tubing is with a manual razor saw. The material is too soft to part it off on the lathe, it will just bend. This manual sawing is very time consuming, but it works and is reliable.
3. the inserts are pressed into the gears using a bench vise.
4. The gears are drilled and tapped for the set screw.

By having purpose made gears I can eliminate steps 1 and 2. The gears will have an ID the same as the brass collars included on each D|Focus. That way I can just press those collars into the new gears, drill and tap.

And since we are going to the effort to make gears, we are making them they way they should be, thicker. They will have the same face width as the lens gears, 0.400". This should make the overall experience easier to setup/align, make it smoother and allow for more focus ring "travel."

Here are the latest renders:

I can't yet say when exactly these will be ready. Tommy, my mold maker is a pro and works very fast, but injection molding is far from trivial. We have a couple of issues and it make take some experimenting to make sure the gears come out right. Expect at least 4 weeks.

Will this effect the overall price of the D|Focus? Probably not. It looks like these will cost much less than the current gears I am ordering, but the initial tooling cost is very high. For now, let me just reassure you all that I am committed to offer the affordable follow focus solution.

All current orders will ship with the current drive gears. However I will have a lot of these new gears made and will probably be able to make them available for a very low cost to existing customers.


  1. Hi Dave,

    I'm currently waiting for my D|Focus to arrive, and I think this new gear will be an improvement (it looks more appropriate too). Will it be easy to replace gears once it's available?

    Keep up the good work!

  2. Oh, yeah very easy. Just a 1/16" Allen wrench and a single set screw. The wrench is included with the D|Focus.

  3. Hey Dave,

    The gear looks great. I gotta say, letting people in on your process helps folks understand what kind of work goes into making your products, and its pretty cool that you keep the price so low as well. Small improvements make a big dif. Thanks for not resting on your initial design and for continuing to tweak.

  4. Thanks Jay. I have some more design tweaks but the emphasis now is on reducing production time.

  5. How many teeth do these gears have, or what diameter are they?

  6. 48 teeth, 1.5 inch pitch diameter, 32 pitch (0.8 mod)

  7. Lets say a put in a order today for the DFocus,, 1 set of gear, and the mount for the 7D. Realistically I will get it by??? Can I expect it by 2/4 the earliest to be delivered or is that impossible.

  8. We are backed up quite a bit right now and new orders coming in will take about 4 weeks to get shipped.

  9. The gear looks good..I appreciate the efforts goes into making these kind of products.