Thursday, September 6, 2012

Tool Review: Jessem Mast-R Lift Excel II (resolution)

I had the opportunity to go to the shop yesterday and reassemble the Jessem Mast-R Lift Excel II following the return of the parts from the manufacturer. I was coming in with high expectations that the problems which had led to an un-flat work table and non-perpendicular spindle had been solved and i could get back to work with this machine.

Unpacking the components, I could see that the table stiffeners had been placed on steroids, so to speak:


The new stiffener is to the left, with the old one to the right. Much better!

Here I've bolted the lift and crank mechanism into place, along with the new stiffeners and the vacuum port:


Next, I assembled the stand's support members to the table, which is taking a different approach than described in the assembly manual where it is suggested that the table be placed on a pre-assembled stand. I changed the assembly sequence so as to ensure that there was no way the stand could place stresses on the table and warp the top:


At last the table is reassembled on the stand, and I have placed a stright bar in the collet of the router so I will be able to check spindle perpendicularity:


Another view:


A look at table flatness:


I checked it here and there and the worse I could find was one spot about 0.0015" low:


Given the likely accuracy of my draftsman's straightedge, which is not a precision instrument, I don't feel I can really conclude that there is a low spot here. I think I can declare the table 'flat' - certainly as compared to the condition it was in prior to sending the carriage and top back to Jessem.

How about that spindle perpendicularity?:


Other side:


The crosswise direction is more critical however:



It seems that we now have a perpendicular spindle. Awesome!

I set the table back in its place and put the fence back on:


I should add that there had also been an issue with the DRO that I was wanting to resolve. When re-assembling the new DRO slide and reader to the table's underside, I noticed that the metal tab on the sliding reader was slightly out of parallel with the magnet on the carriage. I straightened the tab and then the two parts mated flat. Then I ran the machine and adjusted the carriage height with the DRO on. Turning it on and off, locking and unlocking the carriage brake, and keeping an eye on the readout, I noticed the scrolling problem appears to be in the past. There was the occasion flutter back and forth between a pair of sequential numbers, but this is probably because the numerical value being read was in between the two numbers. I'll keep an eye on the situation and see if the DRO keeps working properly. Frankly the DRO mechanism is a bit on the cheap side quality-wise and I may try fitting on a Mitutoyo DRO at some point as I am sure it would be problem free.

The proof is in the pudding, as they say, so I did a bit of trimming on some Jatoba tenon cheeks:


Any flex in the table or weirdness in cutter alignment, or movement in the carriage will produce marks in the cut surface. Here's the clean surface produced by the machine now:
 

Well, I now have a working router table back in the shop and I am pleased at how well this has come out. Jessem found ways to improve their product and I have ended up with a great table. Testing a prototype invariably involves such teething problems and all in all the issues I had with the Excel II were fairly minor matters of a few thousandths here and there. I'm, confident that when this router table goes into production in the near future, that for those willing to spend the money, they are getting a fine product. Thanks for coming by the Carpentry Way, and your comments are always welcome.

21 comments:

  1. so the original table ended up warping as well? guess good thing i didnt hop on to buying myself one right away hah.

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    Replies
    1. Nick,

      no, the original table wasn't warped in and of itself - it was the router carriage that was inducing the warp/sag in the table top due to some slight bolt tolerance issues where the carriage mounted. The carriage became out of tolerance because the mounting blocks to hold the router slug were a few thousandths of an inch too fat, while the holes in the table top for mounting the carriage were slightly too tight. When the carriage was opened up to accept the router slug, it ended up being slightly opened up too much which made the mounting points slightly further apart than they should have been.

      When you're trying to make a precision product, a few thousandths here and there make a lot of difference, and solving these issues in a production setting can be challenging.

      Jessem returned to me the exact same top I sent them, albeit with the mounting holes for the carriage very slightly enlarged, and the carriage router mount pads trimmed slightly. it fit back together perfectly and without distorting the top. I think when this aluminum-top version of the table goes into production, the bugs will have been worked out. This exercise of reviewing the product helped uncover some of the issues in the prototype, and I've found it rewarding to be part of that process. I think Jessem got a lot out of it too.

      ~C

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  2. perpendicularity? Can I use that next time I play Scrabble?!

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    Replies
    1. Dan,

      I think you'll find that a difficult play to make in Scrabble :^)

      ~C

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  3. Oh this is a prototype? But I see it being sold on lee valley already?

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  4. Nick,

    yes, the aluminum top is a prototype. The model sold by Lee Valley, and elsewhere, has the phenolic top, as did the previous model, the Excel.

    ~C

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  5. Whats the Advantage to an Aluminum top? Seems like a machined cast top would cost less and not have the problems like you encountered.

    A phenolic top should be just as flat if the same "steroid" bars are used?

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  6. J Alvis,

    thanks for your comment. The phenolic top, even with the stiffeners, was not adequately flat enough for me. The weight of the router lift in time causes the top to dish down around the tool opening. I am not sure if the new heavier stiffener bars would do much to mitigate that issue with the phenolic top as they are spaced out to the sides to the lift carriage. On the aluminum top version, which is a two piece affair with t-track in the middle, the stiffeners help tie the parts together.

    I was intrigued by the prototype aluminum tool plate top as it promised greater flatness and promises to stay flat over the years, which it delivers on now that the bugs with the lift carriage have been sorted out.

    I might add that a significant feature of the Excel II router table package is the new lift height adjustment mechanism, which in both the phenolic and aluminum table versions is much better than the previous iteration. Having several bearing built in, it's extremely smooth with very little lash, and can be operated without grabbing a cranking tool or stooping over to access the underside of the table. It's definitely the class of the field as far as I'm concerned.

    A machined cast top, like the one Bench dog uses, say, does promise flatness, however my experience with cheaper cast iron tops is that they do not remain flat over time as they resolve their casting and grinding stresses. I've seen this problem on so many machines, domestic and European, that I am not at all confident about how good the B.D. machined cast top would be, especially 5 years down the road. And as for costing less, the Bench Dog cast iron top retails for about $450, while the Jessem top is projected to cost in the $250~300 range.

    I was considering at one point getting some stone machined into a router top, though it would have been expensive.

    Again, the problem here was NOT with the top, it was with the lift carriage inducing loads on the top which caused distortion.

    ~C

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  7. Hi Chris, great thread as usual. just wondering why you prefer the Router table over a spindle moulder. Is it just the tip speed you get from the Router table over the spindle moulder on small cutters ie. 6mm say??

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  8. Steven D,

    thanks for the comment. It's not so much a question of preference between a shaper and a router table. Router tables are generally going to be better when running smaller bits, simply by virtue of higher rpm -- and the smaller cutter on a 6mm/1/4"or 1/2" shank can mold a smaller radius than the cutters on a shaper which is certainly an advantage. Larger cutters in a 3hp router table approach a 'line' after a while where there just isn't enough oomph to do the job.

    With shapers, the part I find discouraging is the fence, which on most shapers, I find is a bit junky and in need of continuous fiddling. Certainly this is the case on the Powermatic I am now using. Shimming fences with bits of paper gets tedious after a while. One can of course shape off of the fence using an auxiliary fence, and I do that sometimes. And shapers are undoubtedly the choice when doing larger scale door and window moldings.

    The perfect answer, for me, is a Martin T-27 with 15hp motor and variable speed drive, with accessory spring collet arbor and sliding table for tenoning. That would do it all, and the Aigner fence on the Martin works very well. The cost however places it well into the future.

    So for the time being I use the router table for most work, and the shaper occasionally for larger template routing (where I'm using a 6" Shelix spiral head and rub bearing). If I had a bunch of doors and windows to make, the shaper would be the more important tool, however I have been making more furniture than anything else in recent years so the router table is suiting me at the moment.

    ~C

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  9. Sounds like a plan Chris. I really like the finish you can get off a well set up shaper. As to the Martin they with out a doubt my first choice. But the money they cost to me is crazy.

    Chris a mate of mine just picked up a Marunaka (Royal Up)and a 600 wide Marunaka grinder in good condition for $1300.00 for both. The Super surfacer needed a new belt which cost $1000.00.. But a great buy none the less.
    Cheers

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  10. Chris,

    For some reason, overhead pin routers never seemed to become very popular in woodwork shops in the states, though you often find them in frequent use in parts of Asia. Used both with and without the center pin. Perhaps they have never been much marketed in your part of the world? If you should ever run across one that also has a head that tilts, they can be quite useful in doing things considerably beyond the capacity of a table router that only has the height adjustment. Makes a good supplement in shops wanting to come up with some original shapes and methods in addition to the more standard ones. At one point years ago, there was a company producing a tilting type in the US, the head raising and lowering via a pneumatic cylinder, but they subsequently went out of business. The plunge capability is very useful. Little demand due to unfamiliarity, i suspect.

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  11. Dennis,

    thank for your comment! Those pin routers, both overmount and inverted types are abundantly available, and can be had relatively cheaply. Most shops that had them have gone to CNC processing centers, rendering the pin router more or less redundant (though a case can certainly be made for them notwithstanding). Onsrud still manufactures several models and I was considering getting one for a while. The problem would be adapting on an easy to use, precise depth of cut adjustment to the lift mechanism.

    ~C

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  12. Glad to hear that Jessem was able to fix the issues. Any idea when they will make it available?

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    Replies
    1. George,

      your comment is appreciated. I can't answer your question however - you would be better talking to Jessem directly in regards to when it will be available.

      ~C

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  13. I am looking to purchase the jessem router lift the new one I believe is called mast. R lift II it comes with tables as a package for 899. Does anyone know if the tables are good? And the lifts work well? Please help I a, considering ordering one. Thank you.

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    Replies
    1. Joanne,

      my experience with the phenolic top was that it was not very flat, which affected the table's performance greatly. They may have improved that now. Certainly the taller stiffeners would help. I've been very happy with the aluminum top version but it doesn't appear they have put it into production for some reason - likely price point.

      The lift itself is good, with the one drawback I have found being that the lead screw which raises and lowers the router carriage is prone to getting gummed up with dust and binding in the brass threading collar it rides in. I have learned to keep on top of this issue.

      The Wixey digital gauge is adequate at best, however to upgrade to something like a Miyutoyo would be hundreds of dollars more, so....

      ~C

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  14. Chris,
    Thank you for your response, I really appreciate it. What aluminum top? How do I get that? I started doing some research, what do you think of the UJK router table from overseas, I don't know if you know anything about that? So, the Jessem $899 kit would be a good option, I would like the aluminum top for flatness. Thank you and I look forward to hearing from you.

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    Replies
    1. Joanne,

      I gather you did not come across the earlier posts on this topic. Here's one that should help from March 8th, 2012:

      http://thecarpentryway.blogspot.com/2012/03/tool-review-jessem-mast-r-lift-excel-ii.html

      As far as I know they have not gone into production with these tops but I haven't been in touch with the company for a while now. You would be best to contact them directly about this matter.

      ~C

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  15. What I like best in your version: the semi-fixed - very flexible - guide. My table is smaller and I am not using the guide very often, but I consider to use your idea. Thanks for sharing

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