Friday, April 21, 2017

A Ming-Inspired Cabinet (94)

Now working on fitting the bifold doors to the client's cabinet, adjusting door width at the sides of the stiles, as before:


A shot of one of the shavings through a tenoned area of the stile, just for kicks:


Planing is satisfying when it is going smoothly. Doors are now fitted to the second cabinet (not illustrated).

On a door-related matter, I purchased the door and drawer handles from Japan, and they come with plastic 2-part cups, as shown below:


The one half of the plastic cup, is like a washer under the nut. After the nut is tightened, the excess threaded rod is snipped off, and then the plastic cap is snapped into place.

I'm not too excited by the plastic bits for these cabinets, and started thinking about what alternatives might be worth a look. For the door handles, the threaded rods can be unscrewed, so it seemed to me that they could be replaced by a countersunk allen button head screw. I looked at a few online bolt supply sites and noted that the closest thread sizes to what I thought I had were M2, M2.5, and M3. I was suspecting these threaded rods were M2.5, however when I got to the shop and put the caliper on the thread, I got a different value:


That does not correspond to any known metric thread standard, including JIS metric thread standard.

I took the threaded rod and nut to a local hardware store to see if I could find something which was the same, and the closest I got was inch-scale #4-40 threaded fasteners. Checking into these later, the standard for diameter for #4-40 thread is 0.1120", which works out to 2.8448mm, pretty close to the caliper measure shown above.

I'm not however totally convinced that the Japanese handle threaded rods are sized to #4-40. It is not far-fetched to think that they might use a non-metric thread standard, as I've seen Japanese circular saws with a 25.4mm arbor (=1"), and found the lock cylinder on a Japanese temple lock to also be inch standard. But, I'm not sure in this case what to think. While a #4-40 threaded rod will fit the brass nut, and the Japanese threaded rod will fit a #4-40 nut, when I tried to fit the Japanese threaded rod to a #4-40 acorn nut, it wouldn't thread in, while a #4-40 threaded rod would thread in to the same nut. So, there appears to be a minor difference in the threads between the Japanese parts and the #4-40 stuff. A bit of a puzzle.

In any case, the threaded rods going into the Japanese drawer handles are more firmly installed, and not easily removed, so it looks like I will have to go with them after all. The handles on the doors could be swapped out for allen bolts however, using #4-40 parts. I'll give this matter some more consideration before doing anything further on this. Funny how some minor things like that can turn into more of a trouble than one imagines initially. Why one earth do they feel the need to use an odd thread size for something so mundane as drawer and door handles? The mysteries of life....

Setting that matter to one side, another hardware task needed to be dealt with and that was enlarging the countersinks on the Brusso hinges to accept #6 screws. I initially tried to do this using a countersink in a portable drill, with the previously-established drill hole in the wood as a guide, however this did not produce clean countersinks by any means:


The mill was the way to go, with a suitable fixture for the hinge the only hitch. I put the Kurt vise back on the work table, trammed it into alignment, placed a block of bubinga in the vise, and then milled a pocket in the block to accept the hinges by friction fit alone. This milling was done with a 1/2" down spiral carbide bit to leave clean sidewalls.

The milling was done from a 0-x and 0-y point, so I had a ready means of finding the offset of the screw holes without trying to measure them directly on the hinge.

I have a set of Weldon 82˚ countersinks to draw from for this task:


This is the 'piloted' set, though the 4 smallest lack pilots. I find these countersinks cut very cleanly. USA made and everything.

With the countersink fastened into a 1/4" collet, I moved the table over 0.75" from the 0-x point, which brought me to the middle of the hinge. The DRO was then reset to make the middle the 0 point for x-travel. Then I simply moved over the y-travel to a point which corresponded to an even inch measure from my starting point, 0.3125" in this case. I strongly suspected that the hinge holes were spaced on some even imperial inch measure from the hinge edges. And they were.

Here's the first countersink:


I moved the table over so I could put a fastener in to check if the countersink was deep enough:


It looked good I thought:


Once depth and positioning was set, all the hard work was done. I now shift the table on x-travel to the next countersink location, in this case, 11/16" away:


Then countersink:


Then shift back to the other side, which is also 11/16" from the middle:


Drill again:


Next, shifting over to the other hinge leaf, using y-travel, the hole centers of which turn out to be 7/8" away from the first line drilled:


Similarly, the other holes on that side are drilled by shifting along the x-travel by 0.6875" each time:


The hinge was popped out of the fixture and it was time for a final check back at stile central:


Zero issues:


Any further pre-drilling into the wood that was required was accomplished, as before, using a suitable VIX bit:


That process, without putting all the screws in mind you, was repeated for the other 11 hinges. The hinges are now all done, save for another bit of patinating and a final application of wax. Another tick off the list.

I set the bifold doors and their hinges aside for the time being and moved on to the bonnet components, looking to complete them and do a final assembly on that unit. First task was to give a final clean up on the curly shedua stand-offs, which I did on the super surfacer, then a last check for fit of those parts onto their sills, and then I could kerf the tenons on the intermediate pieces and mask off around the mortises in preparation for a glue-up:


Wedges also needed to be made - here I'm checking them for thickness at the tenon sides:


More wedges remain to be cut before the glue-ups can proceed, so I'll tackle that task next round.

Thanks for visiting the Carpentry Way. Hope you enjoyed. Post 95 is next.

10 comments:

  1. Wow, that shaving with the tenon in it is superb! I'd frame something like that ;-)

    Regarding the fasteners on the drawer handles, would it be possible to tap new threads? It seems like down the road, it would be nice to be able to buy metric fasteners if they needed replacement, rather than trying to find non-standard sized machine screws.

    Another question- at this stage in the build, do you prefinish any parts before assembly, or does a piece get finished when it's all put together? The bifold doors, if I'm not mistaken, are already finished. Is this because they're already framed in and ready to be installed?


    Cheers!

    --Josh

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    1. Hey Josh,

      good to hear from you - thanks for the comment!

      I agree with you in regards to the downstream hassles of non-standard threads when it comes to replacing fasteners, and maybe tapping the parts to 3mm would be a good plan.

      As far as finishing, various pieces have been largely pre-finished before assembly. It boils down, in most cases, to how the assembly is put together and whether all surfaces are needing finish or not.

      With the dovetailed carcase, the boards received a couple of coats on each side before assembly, and then three coats were applied to the outside after the glue is dried and the joints cleaned up.

      With framed and frame and panel assemblies, you have to either do no finish, or pre-finish each part, or at least the portions of each part which come into contact with one another, before assembly. With the drawers, or example, only the front panel will receive finish.

      With any assembly in which all parts are to be finished, like the bifold doors or the shelves, several coats are applied to each piece in the assembly, with any panel being completely finished and waxed. I don't put finish on tongues or into grooves. Then, after assembly and clean up, there might be some final fitting to attend to - like the bifold doors - after which the outside portions of the stiles receive the coats of finish they require. Then the entire frame and panel assembly can be waxed and then rubbed with steel wool to obtain an even sheen across the parts.

      With certain assemblies, like the shedua stand offs I am just starting to work on again, only some of the surfaces are exposed to view. In that case, I only need to put finish on the exposed surfaces, and given that the through tenons are being trimmed flush after glue up, the course of action is to apply the finish to the outer surfaces after glue up is completed.

      Also, with an assembly like that, in which the stand off fits into dadoes in the surrounding frame work, one needs to gauge how much clearance to give the boards before the finish build up so as to obtain a good fit between parts. It's a drag to put a bunch of finish on only to have to take it all down again because the part is too fat to fit into place.

      ~C

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    2. Thanks for the reply, Chris. Are you worried about uneven expansion/shrinkage on pieces that are only finished on one side?

      --Josh

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    3. No, that's a non-issue. Finishing on one side does not affect wood stability in service.

      See: http://www.woodshopnews.com/columns-blogs/finishing/45-finishing-both-sides-is-warped-thinking

      I have found though, that with thin panels, the application of a water-based finish will temporarily cause the panel to expand on the side receiving finish. Out of a certain share of paranoia that the movement might take a set, I will apply finish to both sides of a thin panel, like the door panels, in close timing to one another.

      ~C

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  2. Hi Chris

    Did you try to use a regular M3 threaded rod?
    very seldom the threads are 3.00 mm in outside diameter even though they ought to be.
    A lot of thin threads are formed instead of being cut in the manufacturing process, so that could explain the slight difference in size.
    If you decide to still use the threaded rods that came with the handles, I would suggest trying to make a copy of the plastic cups out of either brass or even better some dark wood, maybe ebony?
    Brgds
    Jonas

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    Replies
    1. Jonas,

      yes, I did check 3mm threaded parts at the hardware store and they did not fit the brass nuts which came with the handles.

      One option I am considering with the drawers is to recess the nut into a counterbore on the back, the rod being pre-cut to length, and then simply plugging the hole or even leaving it open. at least that gets the ugly visual of the plastic cups out of the way, and leaving it open would make it easier to tighten or remove if need be. Making copies of the plastic cups in brass sounds nice, but with 18 drawers and 36 cups needed, and no lathe, it is more of a hassle than I think worth tackling.

      With any plug or cup, the issue seems to me to be: how convenient is this part to remove afterwards?

      ~C

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  3. you could use the female part of a sex bolt as the nut. that would be a nice clean solution.

    ReplyDelete
  4. Lars,

    suggestion appreciated. Finding a barrel/binding/sex bolt in such a tiny size as 3mm is a problem though.

    ~C

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  5. Hello Chris !

    I know I don´t comment as often as I would like, but I always follow your awesome work since I consider you one of the best teachers and craftmen around the world. It was a huge honour to me being by your side in the LEGNOLAB magazine interview. Well I was just curious about why to test the fit of the wedges in the outside of the tenon, instead of testing them into their kerfts ?? would you be so kind as to tell me yuor thoughts please ?
    My biggest wishes and a huge hug from Spain.

    Julio Alonso.

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    Replies
    1. Julio,

      very good to hear from you and thanks for the question.

      The reason I test the fit of the wedges on the flanks of the tenon instead of the kerfs themselves, is that it is much easier to slip a wedge in and out of a tapered space than it is to put the wedge into the saw kerf, where it would tend to get stuck before you could gauge the fit accurately.

      I only gauge the wedge fit, by the way, when I am sizing the wedges as a step in calibrating my chop saw's wedge-cutting jig. Once I have the wedge cut to the appropriate thickness, I cut the rest of the wedges and they generally fit without any issue as the mortises and tenons are fairly uniform in size.

      ~C

      Delete

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