Wednesday, September 5, 2012

Tool Review: Jessem Mast-R Lift Excel II (bump in the road)

As mentioned in the previous post in this thread from March 9th, 2012, I would put a few hundred feet of material through the new Jessem Mast-R lift II, a prototype with an aluminum tool plate table top. Well, here we are a few months later and I have some developments to report. When I did the assembly of the router, carriage and top, I did an initial check of the aluminum top out of the box for flatness using a Starrett straightedge. It was flat. When I assembled the table and placed the aluminum tracks on each side that guide the fence, I also used the straightedge, and nothing seemed awry.

However, while template-routing some parts recently, I discovered that the cut was not perpendicular to the table top. Puzzled, I began checking some things out and found that not only was the perpendicularity of the cutter to the top seriously out of whack, but the entire tabletop was slightly sagged down in the middle - exactly the same issue I had found found with the phenolic top I had previously used. This was not a pleasing discovery to say the least. Besides the router-cut part being ruined, I now had to take time away from a project and figure out what was wrong with the router table and lift. I use the router table a fair amount and having it down was not a welcome state of affairs. A further problem had cropped up as well: the digital read-out, DRO, for the table was acting quite oddly. When I would apply the carriage 'parking brake' after moving the carriage to the desired setting, and then turn the router on, the setting would scroll on the read out a few hundredths of an inch. This rendered the DRO pretty much useless.

Sorting the router table out has taken the better part of a month, given the vacation I took, along with a recent 4-day trip down to NYC, and vacations also happening with key people at Jessem. One of the facts of life when it comes to testing prototype products is that glitches may be discovered and a step or two back must be taken. As a consumer, on the one hand, and product tester on the other, I was concerned with both getting the problem resolved and interested to see how Jessem would respond. There is no shortage of companies out there who will happily sell you a product and then ignore you - or even blame you - if there are any problems with that product. Some will simply ship you a new replacement, which, if the defect was unique is an acceptable solution, but if the defect was in every product they made then simply shipping a new one to you doesn't help improve anything for anyone.

In any manufactured item there will be the occasional problem-  I'm sure even Rolls Royce has the odd defect. The issue is not that defects occur, but it is how the company deals with the matter and moves forward. Does this spur them to improve the product or not?

I know in my own business that if I produced something which was found to have a problem of any kind by one of my clients, I would be on it right away and would certainly take any lessons learned forward with me in terms of how I would construct the same piece the next time. To this date I have never had a call-back from a customer mind you, and I remain committed to continuous improvement in my work in any case.

Once the problem with the aluminum top and non-perpendicularity of the router spindle had been discovered, it was a matter of tracking down the cause. Since I had checked the top for flatness prior to assembly of the lift carriage to the top and assembly of the top to the table stand, it followed that the top had either warped from some latent stresses working themselves out in the aluminum (an unlikely possibility I thought), or the top had become warped from stresses introduced after the carriage and/or stand were connected. Tracking this down was more or less a process of elimination.

First off I considered the matter of how the Jessem table stand might induce stress in the table top and it didn't take long to rule that out as a cause. I even tried shimming the interface between stand and top in certain spots to see if I could obtain a flatter top. It made little to no difference.

Then I stripped the whole works down and re-checked the top. It was dead flat! So, that left really only one thing - something relevant to the carriage, which bolted to the top and held the router. I tried loosening the carriage and shifting the router slug position slightly to improve perpendicularity, however that resulted in no real improvement. After speaking with Darrin Smith, owner of Jessem, on the phone and explaining in detail what was occurring, he decided to send me an entirely new lift. Jessem would be sending me a new DRO as well, thinking that there might be slightly more play in the unit's linear slide than it should have - a minor manufacturing defect.

The new parts arrived in fairly short order and I commenced the reassembly. The process is one of fitting the carriage to the top, then opening the carriage up using a central bolt which slightly spreads the carriage, and sliding the router slug into position. Once the router slug is at the correct depth relative to the carriage, the central bolt is turned the other way until, releasing the load on the carriage's aluminum chassis and at the same time fastening it tightly onto the slug. Right away I discovered something strange - the new router carriage, having been mounted in the aluminum table top, wouldn't spread open far enough to allow the router slug to slide in. This was a curious difference from the original carriage.

So, I removed the carriage from the top and spread it with the clamping bolt until the router could be slid in place, then released the bolt tension until the router was held firmly in the carriage. Then I went to re-attach the carriage to the top. And there we had a problem, as it wouldn't fit back on! It seemed that the mounting points for the carriage, once the router was mounted, had become spread slightly too far apart and the holes in the top weren't lining up. I fiddled around a bit and managed to actually get the machine screws started into the carriage mounting points, however once I had them tightened up, and had re-attached the cranking handle for the lift, the lift was binding excessively when I tried to raise or lower it. Clearly something was wrong with the picture. So I took it apart again. Something was clearly different in specs between the new carriage and the old one, however given that the parts are CNC-cut in aluminum, I was puzzled as to how the lifts could vary significantly from one another, short of a programming of cutter change. I checked and re-checked the new carriage, and even attempted a second re-assembly of lift, slug, and top, all to no avail.

I then reassembled the old carriage to the router slug and the top. As it had done before, these two parts went together perfectly. 'Perfectly' that is, until I looked at the table flatness and spindle perpendicularity, both of which were as far askew as I had seen previously. At this point I wasn't able to do much more, so I called Darrin at Jessem and made an arrangement to have the top, carriage, and lift picked up by UPS and shipped back, on Jessem's dime, to Ontario so they could investigate the matter further.

I was intrigued to see what they would discover, and hoped that this would lead to improvements in the product. Upon return from vacation I received the following email from Darrin:

Hi Chris,
I did figure out some of the issues you were having. We have only made the aluminium Excel top one time and it was for a special request for one of our important dealers. When these aluminium tops were machined the clearance around the screw holes that attach the carriage shafts to the top was less than we use on our Mast-R-Lift II and less than we use on our phenolic top Excel. That shouldn't be an issue but it actually is because it leaves no room to take the pressure off the shafts if the four clamping blocks are a little tighter. I checked the clamping blocks on the first carriage you had and the second one we sent and they both worked perfect on a phenolic Excel and on a Mast-R-Lift II but were both too tight on your aluminium Excel. The second set was way too tight. We are only talking a few thousands of an inch difference in the hole locations on the clamping blocks but that is enough to make a huge difference when there is no way to compensate for this when the clearance holes are too tight on the holes that the shaft screws go through.
We modified the specs on the clamping blocks and machined a new set to try on your Excel, the phenolic Excel and the Mast-R-Lift II. They now work on all three units with no issues. I checked the squareness of the shaft mounts from your Excel as well and they were pretty close but we faced them in the lathe anyway. The change in the hole locations on the clamping blocks which removed the pressure from the shafts and the facing of the shaft mounts seems to have taken care of the issue with flatness on the top but to make sure I had a set of beefed up reinforcements machined as well to make sure.
The clamping blocks went out for anodizing yesterday and are expected back here tomorrow. We should be able to get your Excel shipped back to you tomorrow.
The squareness issue with the bit to the table I think is a product of the clamping blocks being too tight and no means of relieving the pressure on the shafts. I checked your Excel with the new clamping blocks and it was square to within a couple of thou per inch.
I actually learned a lot from this exercise, we want our products to be the best available so it was well worth the effort to get to the bottom of this. I am planning on making an aluminium top Excel part of our regular line up and I am working on making it even better. When we do produce these I'll send you a new top to replace this one. You should have the best for all the trouble this has been for you.
I hope you had a great vacation and I'll give you a call once you have your Excel back at your place.
All the best,
Darrin

This was looking good - Jessem had been completely receptive to my concerns and proactive in dealing with the issue in a prompt manner. It shows a lot about the character and culture of the company. Despite the inconveniences and frustrations, this has been a good process, even a rewarding one for me personally.

I was keen to see the return of the table and get it bolted back together and then get back to some productivity. The parts are now back in my hands and in tomorrow's post I'll detail the re-assembly of the router table and check out the function and flatness of the machine. I hope you'll stay tuned. Thanks for coming by the Carpentry Way.  On to the follow-up. ☜☜ link

8 comments:

  1. Hi Chris,
    as a french joiner/carpenter, I'm always amazed at the way you seem to re-invent the shaper. For me a router table is nothing more than an undersized shaper with all the problems affixed. I think that, for the price you put into a (not so) decent router table you could afford a second hand german shaper and with a few more bucks even have the tilting spindle, reverse switch, 5 speeds, and so on. Maybe I'm wrong but in Europe we have a pretty big market for second hand shaper.
    By the way, I always like to read from you and I hope you get my English.
    François Pernod

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    1. François,

      nice to hear from you! Your English, from what I can tell, is better than many native speakers, let me assure you. I am pleased that carpenters in Europe and elsewhere are finding it worthwhile to visit this blog.

      I DO have a shaper actually, however it is a Powermatic, and though near new it is not so great. Not tilting, but reverse, 5 hp. Used German shapers do not appear very often on the market here, unfortunately. I was looking at a brand new Martin shaper last weekend, and when I can afford to buy something like that, that is what I will be getting. Router tables have advantages in certain areas, especially where a small profile or skinny stopped dado is required, and router bits are of course considerably less expensive than shaper tooling, however in most respects I agree with you that a shaper is a better choice.

      ~C

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    2. Chris,
      shaper tooling is not so expensive if you do it the french way, which mean a slotted harbour, 6*80mm and a few bars of 6mm tool steel you shape with grinder and files! We still do it that way for the set building i'm doing.
      F

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  2. Hi Chris,

    I hope you take this question in the same spirit as I ask -- an honest question. No intent to offend you.

    After I took up woodworking as a hobby some five years ago, I have seen paying more attention to woodwork and furniture everywhere I visit. I have seen some amazing work by the Japanese woodworkers. I also saw some in India where the craftsmanship is just amazing (the "Indian Handicraft" junk I see here in the USA comes nowhere near it). The joints in a entry door were perfectly together even after forty years. What astonished me is the "primitive" tools that were used in building some this furniture (of course, I don't exactly know what tools were used in all those pieces which impressed me but power tools are quite rare in most of India). Chisels were sharped on piece of wood with some fine sand as abrasive -- extremely primitive.

    I read your blog regularly and know how much you care for accuracy in your tools. I admire your skills too. So, my question is this. Do you really need this super accurate gizmos to build quality furniture when people seem to have built quality furniture with just hand tools. Or, does the furniture you build is an order of magnitude better than what one sees commonly (say, Japan, China or India)?

    Thanks for the thought provoking posts as always.

    PhilM

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  3. Hi Phil,

    thanks for the question. There are lots of facets to that question.

    It is definitely the case that high quality work can be, and has been, produced with hand tools alone. Chisels and planes can produce high quality surfaces that are very flat and true.

    It is amazing too what can be accomplished with poor quality tools, however I am pretty sure that most craftspeople prefer better tools if they can obtain them. Many woodworkers seemingly learn to live with poor tooling and ill-adjusted equipment even if they have the means to correct the problems.

    Now, if you look at the evolution of Japanese carpentry joints there is a fairly clear connection between improvements in hand tools and increases in the sophistication of joinery around 1600. Some will argue however that while certain improvements in tools make for positive changes in one direction - like the development of the rip saw which allowed wood to be sawn without concern for the run of the grain - often entail shortcomings in another direction: that carpenters could ignore run of grain by sawing instead of riving meant a loss of sensitivity to material and the use of sawn parts which would often be weaker than their riven counterparts.

    Some will argue that the sort of carpentry done with the 'primitive' tools, like axe and adze, is more pleasing due to its inherent imperfection and irregularity. Imagine sitting in a room in which a window on one side had slightly irregular riven bars in it, and one on the other side had perfectly straight and machined clean bars. The feel of the view out each window would be pronouncedly different.

    In one sense, what constitutes a 'primitive' tool and what constitutes a 'sophisticated' tool? If one is to be a purist, I suppose, then stone tools are really the only way to go, and the handsaw an unacceptable corruption. There are accounts of the native Indians on the Northwest Coast of Canada being given steel tools to use on wood and then returning the tools later as they evidently found their stone tools more satisfactory. A lot of what constitutes tool use is what is available and what is conventional.

    On one hand, a chisel is a 'simple' tool, however the technical details of forging are a rather deep pool of knowledge, so one could argue that, at least in the case of Japanese chisels, they are anything but primitive.

    And I think it is likely that if you offered a high quality Japanese chisel and a few sharpening stones to a guy in Indonesia who was used to using a chisel made from an old car spring, he just might decide he prefers the Japanese chisel. I certainly can tell the difference in quality between one chisel and the next, and I'm sure you can too. But if you never saw a Japanese chisel, and the normal thing was a chisel made from a car spring, then I'm sure you would simply just get on with the work.

    ...to be continued...

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  4. ..continued...

    Another thing you see in a lot of third world countries are crude woodworking machines without any safety guards or protections on them whatsoever. You'll see construction workers on sites in Japan using thin shoes without steel toes, while over here OSHA would be all over them. Would one also argue that since wood can be cut on primitive equipment without safety provisions that we are all a bit namby-pamby over here in the west, wasting our money on non-essential 'peripherals'. I tend to think not, of course. Table saw accidents are altogether too common and hence the popularity of Saw Stop among many woodworkers in in recent times.

    In response to your question, "Do you really need this super accurate gizmos to build quality furniture when people seem to have built quality furniture with just hand tools."

    I'm not totally sure what you mean by 'super accurate gizmos' - Perhaps you refer to the DRO? Well, to me, that is simply a glorified measuring device and nothing more. It is more convenient to read than squinting at a ruler.

    What I seek in equipment -what I NEED- is actually rather simple: a machine needs to do the thing it is meant to do without fuss or being dangerous. If it is meant, say, to saw with the aid of a guide fence, then that fence and blade need to be aligned to one another and the table flat. The fence edge should be 90˚ to the table. The spindle needs to have minimal run out. The table and throat insert need to provide a flat surface. The further you move away from those basics being executed well the further one moves into un-predictable, unsatisfying, indifferent or even dangerous outcomes. If the machine can execute the basics well, things tend to be smooth sailing for the most part.

    With a router table, having a flat surface and a cutter which is perpendicular to the table top are the primary basic functions in my view - these are , or should be, givens. Sadly, it would seem to be the rare machine in this world of woodworking gear that can perform the basics well, time and again, in my experience. Again, depends on how carefully you are looking, and what your expectations might be. some like to tinker on their machines, i just want them to do their job and let me get on with the working of the material.

    Let's consider fitting a mortise and tenon. Once the parts are together, so long as the tenon shoulders close up tightly to the mortised piece, the joint looks good. However the tenon may not actually be a good fit inside. In fact, it is easier all round to make the tenon a sloppy fit as it facilitates assembly in most respects. But a sloppy fit renders the joint a failure in mechanical terms. I've seen many attractive joints that when taken apart reveal poor mechanical inter-fit between the parts. A lot of woodworkers, if they look at what they are doing, will realize in a lot of their 'joinery' they are relying on the glue to do the mechanical joining. I've seen a lot of poor joinery in timber framing as well, both in design and execution. So, there's more going on than simply how it looks on the surface.

    ...to be continued...

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  5. ...continued...

    Then you wrote,

    "...does the furniture you build is an order of magnitude better than what one sees commonly (say, Japan, China or India)?"

    I can't really speak to that, nor is that any sort of goal for me. I aspire to construct pieces with the same attention to detail and use of quality materials as the ones I admire and seek to emulate. I'm trying to do the work carefully, in a way that I enjoy, and to construct pieces which will last for generations. I take my cues in how to build from past examples that stood up over time, but I do not feel any need to use the same tools as woodworkers in some particular country or time period used, nor to dress as they did, eat what they did, live in the same social arrangements, pray to the same god(s), etc.

    I live in a time and place where I am fortunate to have a few choices and, at least once in a while, the economic means to buy tools at various quality levels, and try to get the best I can when I can. I don't want to settle for inferior results in my own work, nor do I want to settle for inferior equipment for doing that work. In other areas of my life I am not nearly so concerned about such things.

    I'd rather not pitsaw planks of rosewood out of a log or hand hew every plank. I like to cut joinery. I like to design. I like to hand plane. I'm lucky in many respects, however I think if i didn't have the access to tools I would still be doing woodwork, still trying to achieve the best results I can. "Run whut ya brung" as they say.

    ~C

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  6. It is really hard to manufacture tools because a little mistake can make all the tools useless. For example if size of a screwdriver is not universal it is useless. So workers in the factory should pay attention to the work to avoid these issues.

    ReplyDelete

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