Amateur Build of the X-MTM Encore

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jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #40 on: 19 Jun 2020, 08:57 pm »
Not sure about the terms you are using, but this appears to be the saw:
https://c.searspartsdirect.com/mmh/lis_pdf/OWNM/L0911390.pdf

diyman

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Re: Amateur Build of the X-MTM Encore
« Reply #41 on: 19 Jun 2020, 10:34 pm »
That's a contractors saw and the entire weight of the motor and blade assembly is suspended from bottom of the cast iron table.  Which is what can cause the cast iron to warp, although it doesn't seem to be too bad with yours.  If things are very flat from just left of the blade to the fence on the right side, then you can probably get pretty square cuts.  Don't try to do any cuts where the offcut piece would extend more than an inch or so to the left of the blade and you should be alright.  Also make sure that the throat plate is level and flat with the rest of the top.

The rise to the left of the blade is a little hard to understand, but now that you know it's there you can avoid it.  So doing crosscuts might be a problem.  If it is, then you can solve it by building a crosscut sled.

Most importantly, make test cuts with good flat wood and check them with a square every time you change the blade angle.  Don't trust square up blade readings made on the table top itself.

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #42 on: 20 Jun 2020, 01:02 am »
Good advice.  I do usually make checks of its cuts.  Now I may know where to look and what to look for.

In looking at it, the high spot is more forward than where the motor assembly is bolted and I can’t find a low spot.  If I had to guess, it might have had the “droop” and someone before me (I bought it used) tried to press it out with something like a press or hydraulic jack.  That would explain the push-out.  It is all a guess, though.

Thanks for the heads up...   :thumb:

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #43 on: 22 Jun 2020, 11:39 pm »
Christmas in June!   :lol:

It is great when I send myself presents.  That is the best part about ordering on line.  When it comes and lands at your doorstep, it is another package to open, just like a kid at Christmas.

This time, for me, it was an order of clamps from Harbor Freight.



This is a place where I am careful of what I buy.  The clamps they sell have given me few problems, and the main problem they have given me (the ratchet fails) has been easily fixed.

Now I know I don’t have enough for every joint and junction that needs to be made, however my plan is to use some oak board I have to span across a few of those places without loosing clamping pressure.  I’ll let you know how that goes, later.   :green:

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #44 on: 24 Jun 2020, 02:10 pm »
It seems that life in general has a habit of getting in the way of progressing on projects like this.  I recently got this YouTube post recommendation of a few guys who put on this 3 hr long concert:

https://youtu.be/rUZmZEujeE0

I don’t know anything about them*, but they sounded really good.  Or at least I thought that they might sound really good if I had this project done.  I definitely need to get going on this...

(* Ok - that’s not true.  :icon_lol:)

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #45 on: 28 Jun 2020, 02:07 am »
A little more work done.  I want to thank the 2 members who’s advice has been quite timely. 

I have have looked over the table saw table some more and my conclusion remains.  It has a small bump in the cast iron.  I am sure it was not manufactured that way as I can seen the surfacing marks on it from when it was originally manufactured and this bump is within those.  This bump is only to the left of the blade.  It is not to the right of the blade, which is helpful for now (only dong ripping; no miter cuts for now).  As a result of suggesting that I check the flatness of the  table, I now know that I need to square the blade to the right side of the table.  After I did this, I looked at how square the blade is to the left side, with the bump and it is off about 0.015” to the top of the 12” blade, fully up.



To go along with the newly squared blade, I added a enhancement to the rip guide:



this is that piece of 2“x1”  rectangular tube that I used when using the router to cut out the pieces from the full board.  A while back ago, I found that from the top to the bottom, the rip guide isn’t square.  You can see the piece of wood wedged between the tube and the saw’s rip guide to hold the tube square to the table.  The tube also extends well beyond the table to make sure the longer pieces being cut are held flush.

The second piece of advice that I have made part of my work is to make my cuts a touch on the high side.  To help with that I marked each panel with which corner I knew to be square when I cut it from the larger board:



This way I know which way to feed the panel though the saw and I know which side to measure from for laying out the cut.  I also add the planned dimensions for the panel.  When I was done cutting the width of the panels was about about 1/32” over.

I did the final sizing cut on the side panels.  Now everything is cut to size.  And, the edge I cut is square to the face; I checked. :green:

Next is to set the router table for 3/4”x3/8” relief grooves in edges of the front, top, bottom and side panels.  I have not quite decided how I am going to do this.  I know some of this will need to be done with the router using a straight edge (for the shorter cuts).  For the longer cuts it would be nice to do them on the router table, but it is not the best table ever made.  I am also considering doing a 3/8” deep cut on the table saw prior to dong the actual routing.  All of this will take some practice and experimenting.  More to come... 

diyman

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Re: Amateur Build of the X-MTM Encore
« Reply #46 on: 29 Jun 2020, 07:04 am »
Be sure to make the relief grooves in the edges of the front, top, bottom and side panels slightly wider than the thickness of the mating pieces that will go into them.  Add at least 1/32", or even 1/16" just to be on the safe side.  Then after the glue up route off the excess with a flush trim bit.  If you try to make them fit exact and miss, then you'll have to sand off large areas of the mating panels.  Not good.  And you'll never be aware of the very slight difference in the overall size of the boxes.

All of that assumes you have already cut the pieces to their exact final dimensions.  If you haven't done that yet, then you can cut them slightly oversize and make the box exactly to plan.  However, it doesn't really matter either way.   

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #47 on: 29 Jun 2020, 06:15 pm »
That will be my plan.   While everything has been cut, I did plan in a little overage.  Now to find out if there was enough overage planned in.  :o

I intend to do practice pieces to see how the routing and fit up goes.  Then I will do a dry fit up of the actual outside panels when I am done with the routing to see what success I have.  I figure I can trim a bit more to widen the relief if I need to make sure there is a touch of overage.  The plan is to have the back panel fully fit within the reliefs cut into the sides, top and bottom.  I am figuring that PL glue that Peter uses will take up any gap.  If I just use the Tite Bond all around, then the fit up gap needs to be tight, which will be hard to do, or the clamping force will need to be high enough to bend the panels.  I think both of these options to be less desirable than taking up space with the PL glue.  The last bit of the assembly will be dry fitting the braces.  Here, again, I plan to use the PL glue in the final assembly and any gap will be accommodated.  I am also figuring that the PL glue will add a bit if damping to the structure instead of it being ridged.

There have been comments made, in particular to Danny’s videos, where there is clear nervousness about taking on one of the DIY projects.  Now that I gotten into one of those projects I can see where this nervousness might be coming from.  I have made a few things over my lifetime, but I find that while these speakers seem to be just simple boxes, there are details, such as this, that need to be well thought out.  Those details can be a source of hesitation for some. “How do I get through this?” sort of thing. I am pretty sure I can “puzzle” my way through this and I expect it to come out well, especially given the advice that is available.  I hope that recording my efforts, and thoughts, along with the thoughts from others about making a set of these speaker is found to be helpful by another DIY’ers and provides ideas as to how to come through details of building these, which, in turn, encourages them to take on one of these projects. 

diyman

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Re: Amateur Build of the X-MTM Encore
« Reply #48 on: 30 Jun 2020, 06:10 am »
I am figuring that PL glue that Peter uses will take up any gap.  If I just use the Tite Bond all around, then the fit up gap needs to be tight, which will be hard to do, or the clamping force will need to be high enough to bend the panels.  I think both of these options to be less desirable than taking up space with the PL glue. 
PL is not a glue.  It is a construction adhesive and not a good choice for speaker cabinets.  It only has about 1/4 the bond strength of Titebond Ultimate.  Make sure your cuts are square and Titebond will work fine.  Then run a bead of caulking along all the inside corners of the speaker cabinet, just to make sure it's sealed up.

Peter J

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Re: Amateur Build of the X-MTM Encore
« Reply #49 on: 30 Jun 2020, 02:24 pm »
I'd like to clarify since I'm being cited as an information source :)

 Please don't assume that because I use PL Premium in specific situations that it's a replacement for wood glue like Titebond or reasonably accurate wood joinery. Definitely not a case where "one size fits all". I sometimes use products in unconventional ways, but they are always well-considered and rarely represent a panacea.

Although the strength of either will likely exceed the requirements of task at hand, wood glues exist for a reason. Although it can conceivably be done, I'd say there's nothing to be gained for substituting PL in the case of speaker cabinet building in general.

I question the value in smearing a bead of caulk on the interior seams, although it probably doesn't hurt anything. It's not a sealed cabinet so airtight-ness is not much of a consideration. I see it done frequently and it's an idea that's perpetuated by many, but I fail to see the advantage it provides in an assembly such as this.

Climbing off soapbox now...

WGH

Re: Amateur Build of the X-MTM Encore
« Reply #50 on: 30 Jun 2020, 03:17 pm »
I am figuring that PL glue that Peter uses will take up any gap.  If I just use the Tite Bond all around, then the fit up gap needs to be tight, which will be hard to do, or the clamping force will need to be high enough to bend the panels.

The strongest woodworking joint has a very thin glue line, the PL Premium will have a fat joint resulting in a slightly askew alignment and a wide glue line that will be very hard to finish. If clamping force is too high you will squeeze out all the glue and the joint will have have zero strength. Cleanup with PL Premium is paint thinner, Titebond cleanup is water.

Since woodworking is new to you I would recommend Titebond Extend, the slow set version of Titebond Original. Gaps in the finished cabinet are usually filled with Bondo auto body putty after the glue is dry and the joints are sanded flush.

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #51 on: 30 Jun 2020, 03:21 pm »
Peter - Thanks for responding.
Your point is well taken.  I had seen in a couple of your videos where you used the PL adhesive for attaching some internal bracing.  I also noted that you said this was an unconventional use of this product.  I believe in one case you used it to attach the small diagonal braces (Sorry, could not locate the video for this one) and another was to attach a dowel brace:
https://youtu.be/5n3ZYGnEjgE

Honestly, your videos have been a source of inspiration for me and I greatly appreciate you taking the time to make and post these.  I didn’t mean to come across as saying “Peter said to do this”.  Only that you were a source of inspiration for what I plan to do.

Your use of the PL adhesive for the braces gave me an idea for how it could be used in the assembly of the braces in this speaker design.   That is, use the PL for the internal braces, where there may be clearances and variations in dimensions of the pieces I have made, and, as a result there may be gaps too large to make good use of the Titebond.  I do plan to glue the main part of the cabinet with the Titebond.

Here are my thoughts (right or wrong - comments welcomed. :thumb:):
I don’t have the wherewithal to make these braces with the precision needed to ensure that all of the pieces will fit exactly, without one piece pushing on another piece or having gaps too large for conventional glue.  I see this happening with the internal braces in this speaker design where one brace may be either slightly smaller or larger than any other pieces, which may in turn affect the “size” of this cabinet.  I want the “size” of the cabinet to be defined by the external panels.  Additionally, I will need some “slop” in the location of the slots for the braces to absorb any misalignment from side to side resulting from any inaccuracies from locating the slots in the panels.  Therefore, all of the internal braces will need to be undersized and the slots into which they will be fit will need to be slightly oversized.  The PL adhesive seems to be a good solution for this application as the bonding would seem to be less gap sensitive.  I am not talking huge gaps here.  Maybe 1/32nd to 1/16th, but I figure any gaps of this size will not glue well with the Titebond.

As I said, I plan for the rest of the cabinet to be assembled with the Titebond.

I see this speaker as being a more difficult one to do the assembly on because of the 7 braces in it and the front  panel needing to be installed at a later time, so the no-Rez, crossover and wiring can be installed.  Right now I am puzzling through how best to do this within my abilities.

I do appreciate other people’s thoughts here... 

Peter J

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Re: Amateur Build of the X-MTM Encore
« Reply #52 on: 30 Jun 2020, 05:15 pm »
Jon, the only place I've recommended PL is the pocket for the dowel brace on the X-LS. Here's the thing with most all polyurethane adhesives; they expand to some degree when they cure. In the case of the dowel, the slow cure and expansion is right for the task. I purposely left 1/16" clearance side to side and about .010 around circumference of pocket.

In this specific case, I wanted the dowel not to interfere with assembly of the rest of cabinet, hence the clearances. As the PL cures after the cabinet is clamped up, it expands to fill the potential void at bottom of pocket and "pressure" is relieved via the side clearance.  It's gnat's eyelash stuff, but it's how my mind works.

In your case, I think the expansion might actually be a detriment, as there's no method of clamping or restraint, so it effectively pushes brace away from surface and results in a less-strong bond, that's solely dependent on the shear strength of the adhesive, not good.

I did use Titebond III, or what they now call Ultimate, on the panel to panel diagonal braces. It has a little more viscosity and "suction" than Titebond I but either would work. It also has a tiny bit more gap filling qualities than Titebond I.

You should be able to get a reasonable result  with the tools you have. I don't think I'd spend much effort on textbook perfect joints. I get your reasoning, but in all honesty, you may be swatting flies with a sledgehammer, but only you can judge what you're looking at there. 

Bear in mind, all speaker cabinets don't have to withstand the "truck" test to be viable.

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #53 on: 30 Jun 2020, 07:40 pm »
Peter - thanks for taking the time to help me with this.

Jon, the only place I've recommended PL is the pocket for the dowel brace on the X-LS. Here's the thing with most all polyurethane adhesives; they expand to some degree when they cure. In the case of the dowel, the slow cure and expansion is right for the task. I purposely left 1/16" clearance side to side and about .010 around circumference of pocket.

In this specific case, I wanted the dowel not to interfere with assembly of the rest of cabinet, hence the clearances. As the PL cures after the cabinet is clamped up, it expands to fill the potential void at bottom of pocket and "pressure" is relieved via the side clearance.  It's gnat's eyelash stuff, but it's how my mind works.

Peter - your description of the clearances on your dowel assembly is almost exactly the same as my plans for the internal braces.  There will be a pocket with about 10 mil clearance to the sides of the pocket and some amount of clearance between the panels of the cabinet and the brace (your 1/16th sounds good for that).

This is a mockup of what I already tried out.  The left side is gluing using the TiteBond and the right side is the PL adhesive:



And here is what the PL adhesive looks like in the joint.  Note that the magnified section in the top of the picture is the TiteBond and the bottom magnified area is the PL adhesive.  This was, in part, what I based my decision on:



Yes, the pieces making up the pockets (light color wood) are less than square.  But that appears to show the sensitivity of the TiteBond to excess clearance.  This amount of clearance is probably along the lines of what I will have.

The final assembly will use 1/2” quarter round instead of the 1/2x3/4 stock in the mockup.


...  you may be swatting flies with a sledgehammer, but only you can judge what you're looking at there. 

Bear in mind, all speaker cabinets don't have to withstand the "truck" test to be viable.

 :lol:
You are absolutely right.  Overthinking things.  Or is it procrastination?  I am probably good at both...   :duh:
And it would not be the first time that I made something that could support a “truck” just to carry me..  :roll:

“...only you can judge what you're looking at there. ” - I appreciate this.  Actually, I think I am on the right path and you have “filled in” one thing about this that I have been pondering.  That is, the gap between the braces and the cabinet panel...

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #54 on: 1 Jul 2020, 12:46 am »
Ok, I haven’t done any routing on MDF, but this stuff isn’t working the way I hoped.  I am doing some practice running runs, and a good thing too.  At the end of a run the router will chunk off a piece.  This happens no matter how slow I put the piece through.  I am using a brand new Amana 3/4” dia 2 flute router bit on a Craftsman hand router mounted in a table.  Now, the chunk isn’t harming anything.  But, it didn’t seem right...

Any help/advice?

AlexH

Re: Amateur Build of the X-MTM Encore
« Reply #55 on: 1 Jul 2020, 12:59 am »


clamp a piece of wood on the side of the mdf that the router bit will be exiting on.  This will help to prevent tear out. Does that make sense?

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #56 on: 1 Jul 2020, 02:02 am »
Actually, yes it does  :thumb:
Thanks, I’ll give it a try.
Now I just need to get those longer clamps...  :duh:

diyman

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Re: Amateur Build of the X-MTM Encore
« Reply #57 on: 1 Jul 2020, 06:19 am »
Jon,

You seem to be doing some things in a very unusual manner and I think it's making the project more difficult than it needs to be.  These are things that have been done many times before by woodworkers and speaker builders, so there really is no reason to invent new approaches that are actually more work and less accurate.

I’m speaking specifically about the idea of adding parallel pieces to the insides of the panels to form a pocket for the internal braces.  This is much more easily done by simply routing a dado that is the same width as the thickness of the bracing material.

If you can’t find a router bit that matches that dimension then there are well established techniques for routing the dado in two passes with a slightly smaller bit. You can get essential a perfect fit that way, and it’s not difficult to do.

You should be able to find some YouTube videos that show you exactly how to do it.  Let me know if you can’t find any and I’ll look for them for you.

jonsk2514

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Re: Amateur Build of the X-MTM Encore
« Reply #58 on: 1 Jul 2020, 12:56 pm »
Nope, I am not one to follow conventional wisdom.  :o

I have given consideration to routing grooves in the panels for braces and concluded I needed to do something different given what I have available to do this.  I had 2 major considerations. For me, all of that would have to be setup and routed with a hand held router.  With 7 brackets, 2 or 3 panels and 2 speakers that would be 28 or 42 separate setups and cuts to make.  Then there is the precision to which these will all have to be done.  I know the MDF is slightly thinner than a standard 3/4” router bit, but it is still a snug fit which will require a bit of side to side precision.

And a big factor for me was how to control all of that dust...  I have little in the way of dust collection ability and what I do have is centered around the stationary tools I have.  Using a hand held router would require the fabrication of dust collector system for it.  And then there is my personal disdain for hoses and wire/cords that have to follow me around and are very adapt at following Murphy’s Law (if there is something for them to get tangled on, they will always move in a way to get tangled).

The practice pieces I did was to test out my idea.  For me it was simple to do.  Bear with me on this one.  Hopefully you will see how this works for me.  Or I fail, miserably...  :bawl:

mlundy57

Re: Amateur Build of the X-MTM Encore
« Reply #59 on: 1 Jul 2020, 05:41 pm »
Dados, pockets, etc. make alignment easier but are not essential. Butt joints are plenty strong. Adding additional material reduces the internal volume and can affect the tuning. If you want to use the pocket idea to keep alignment, don’t glue the pieces to the cabinet. Cover them with packing tape so glue won’t stickto them and clamp them to the cabinet until the glue on the brace Is dry then remove the guide blocks. Be sure the pieces being glued are aligned front to back. You don’t want anything overhanging a side.

You glue the braces to one side at a time. The trick is going to be keeping the sides aligned and square. One way to do this is make the top and bottom the same size as the full length braces and the side lengths the overall height of the cabinet. Glue the top and bottom pieces on at the same time as the internal braces. After the braces and ends are glues to one side, glue the back on making sure the ends and braces are square. Then glue the other side on keeping all edges aligned.