Clock Drive Review
John Hayes, Ph.D,
Adjunct Research Professor of Optics
Optical Sciences College, University of Arizona
December 18, 2012
While looking for a clock drive for a custom telescope mount I am building, I came across the Optic-Craft Machining website. Since I needed a custom base to fit my mount, I was happy to see that Optic-Craft Machining offers "custom machining". Because I am trying to build a mount that will break down in a compact size yet support a number of telescopes, I wanted a compact drive configuration. I requested drawings of the 5.6" Optic Craft "Pollux" drive, but was instead sent photographs with hand marked dimensions. So, I proceeded to design this drive into my mount. When I first submitted the order, I supplied a drawing with notes, specifications, and tolerances like I've done with every machine shop I've ever dealt with. Mr. Clinard, the owner, expressed concern over some slotted holes on the first set of drawings and indicated that some of the dimensions on my drawing that came from his photographs were incorrect. I suggested that the requirements were very easy to meet with any milling machine, but that I could probably modify the design to handle simple, oversized holes rather than slots. I modified the drawing and sent him the drawings shown in the figures. With the custom "machining", anodizing, and a little extra wiring, the price came to $984. I couldn't find any detailed reviews of Optic-Craft products, but Optic-Craft has been around a long time and they claim a long list of 100% satisfied customers so I wrote a check for the full price and took my chances. Delivery took about 8 weeks and when I received the drive here is what I found:
1) The drive component dimensions that were delivered are not even close to what was sent to me in the photographs. The main spur gear is a very light duty, narrow contact gear made of brass. The website specifies an anodized aluminum main gear.
2) The main brass spur gear is chopped up with multiple dings, flats on the gear teeth, score marks, and damaged teeth. The gear was completely bubble wrapped and was clearly not damaged in shipping. As a clock drive, this gear is completely unacceptable. The photographs below show the condition of the gear as it came out of the box.
3) The surface finish on the main spur clutch parts are the worst I have ever seen. This thing appears to have been rotary sanded with a 150-grit wheel and then anodized.
4) I measured the hole for the shaft and it looks like it is right on the money (1.9990"). Unfortunately, the setscrew holes were drilled AFTER boring the main shaft hole and the setscrew holes have large burrs that were not removed. These burrs will NEVER allow the drive to fit over a precision shaft.
3) The mounting plate for the worm gear is "interesting." None of these cuts were done on a milling machine. This thing appears to have been scribed, rough, cut and filed. All of the edge breaks are non-uniform and demonstrate poor workmanship.
4) The rod end spherical bearing mounts appear to have been hacksawed to the about the right length. One of them is mounted completely crooked. The surface of one of them is scratched and marred up like it was held by a vice grip.
5) The worm gear shaft is clearly not aligned with the base in any axis. By eyeball it can easily be seen to be crooked in all directions. As an engineer, I believe that it is completely unacceptable practice to compensate for poor manufacturing tolerances with slots and holes. There is no way to sugarcoat it: This thing is a complete mess.
6) All of the hardware is either black oxide or course thread (UNC) nickel-plated screws. Black oxide screws corrode in no time and many of them on this thing are already coated with a layer of rust. I learned a long time ago that quality instrumentation requires stainless components or you end up with a rusted out mess. This is the kind of equipment that benefits from UNF threads. UNC threads are totally out of place for this kind of equipment.
7) I had requested that connectors be put on the wiring and that wasn't done at all. The control box is short wired to the drive motor, which is EXACTLY what I had instructed not to be done. I could talk at length about professional quality wiring, but I'll stop there.
Here is the drawing and specifications I supplied with the order:
Here is how the worm gear assembly looked straight out of the shipping box. Using lamp grade zip cord and bare wire
solder joints does not create a very professional first impression.
The main spur gear-clutch assembly right out of the box. Note the rusty set screw and nickel plated UNC clutch plate screws.
None of the holes are drilled in line. Also note the out-of-round counter-bores. These appear to have been done
with an end-mill on a drill press. Tolerances appear to be in the range of =/- 0.10" - far in excess of the specifications
agreed to in the drawings.
Note the scribe lines. This part was not machined as I expected. It was scribed, rough cut, and filed. It is a reasonable
expectation that any business offering "custom machining" would have a milling machine. It is obvious that none of this
work was done on a mill.
Nothing is square - not even close. Proper gear engagement will be difficult to achieve. It is extremely poor practice to
compensate for poor manufacturing tolerances with oversized holes - especially with poorly positioned, oversized holes.
Rusting, black oxide hardware appears to be standard.
I exchanged a number of emails with Mr. Clinard over the quality of this drive with comments very specific to what he delivered. He responded by telling me, "Quality is your conception, not mine. I do not know how to answer your quality questions in light of never having a problem in the past 23 years of making drives from my numerous world wide customers." He never once directly addressed the detailed list of problems that I sent him.
I have over 30 years of experience designing and building precision opto-mechanical instrumentation and dealing with "real" machine shops. Based on his response, I realized that Mr. Clinard was not going to be able to resolve my concerns and I proposed returning the drive for a refund minus a fair "restocking fee" plus all shipping costs. He refused. He did eventually offer to exchange the spur gear if I would return the unit to him and pay all shipping. At that point, I refused to pay him anything - for shipping or anything else - and I gave up dealing with him. 23 years is a pretty remarkable record for "never having a problem" but this is the end of the road for that streak. This product does not meet my expectations in any way.
Here are my conclusions based on this experience:
I saw no evidence that Optic-Craft even has a milling machine. Optic-Craft Machining did not deliver the kind of machining services that any experienced engineer would expect from any shop offering, "custom machining". I have never seen anything even close to this level of quality delivered from any of the reputable shops I have dealt with in the past.
All claims of precision on the Optic-Craft website are unverified by what I received. It is very hard to believe that Mr. Clinard is able to deliver anything that meets any specification based on how well the parts he delivered conformed to the drawings I supplied. Everything was out of spec, sloppy, damaged, improperly fabricated and poorly made.
Mr. Clinard managed to sweet-talk me into paying full price up-front, which went against not only my better judgment, but my experiences with every reputable machine shop I have dealt with in the past. This should have been a red-flag.
In response to my concerns, Mr. Clinard was very defensive and he expressed no eagerness to "make it right". Once I saw the quality of the product, I refused to pay anything beyond my original payment. I believe that his offer to supply a new gear was simply an attempt to extract all of his shipping costs.
Mr. Clinard was unwilling to supply drawings of his products up front. In one of his emails, he claimed to have a patent on his designs so that he couldn't give out drawings. If he really had a patent, he wouldn't have to worry about copying. The website doesn't show any patent numbers and the product is not marked with any patent numbers, so I searched the USPTO database and there are no assigned patents to either Mr. Clinard or Optic-Craft Machining. Claiming to have a patent, claiming that such a simple design is secret, and refusing to provide accurate dimensions or drawings is another clear read flag.
I cannot recommend this product to anyone. I would also urge serious caution to anyone considering doing business with Optic-Craft. My attempts to resolve this in a fair way were rejected and I did not experience a very high level of integrity when I tried to get this resolved. Mr. Clinard was unwilling to stand behind the quality of this product.
After this review was posted, Mr. Clinard contacted me privately to reopen our discussion about resolving this issue. After our initial discussions ended, I felt that I owned the drive and my intent was to review it as a community service--not to leverage a more favorable response. However, I wasn’t out to destroy Mr. Clinard’s business either so when he contacted me, I felt that it was reasonable to give him a second chance to make it right. Mr. Clinard eagerly agreed to refund the price of the drive minus a 10% restocking charge and I agreed to pay all of the shipping. The deal is done and he has refunded my money and I have returned the drive.
Mr. Clinard has assured me privately that this drive did not meet his standards and that he will redouble his efforts to delivery high quality products. He has also publically stated that he will always try to make it right and if he can’t, he will stand behind his products with a money back guarantee. It’s unfortunate that we had go through this process but in the end, I believe that it has had a positive effect on the market and I applaud Mr. Clinard for ultimately doing the right thing. He and I both learned a lot from this episode and I believe that Mr. Clinard will be very responsive moving forward. We have since had some very friendly conversations about how to delight customers and I certainly hope that he receives fair consideration in the future.