# lock miter bit...again



## sreilly (May 22, 2018)

So I finally found a source for Baltic Birch plywood in 1/2" and 3/4" but they're in 5'x5' sheets. So layout will take more thought as I'm used to 4'x8' sheets. But I digress, what I'm mostly interested in is how well the lock miter bit will work on 1/2 Baltic plywood. I tried it on the box store's plywood and it was disastrous. The tear out was horrible all along the cut but I'm wondering if it was because of the quality of the plywood. I also have both the 1/2" and 3/4" Infinity Tools Lapped Miter Joint Router Bit which I suspect may work well on plywood drawers? Any feedback on if Baltic plywood will yield better results and if the Lapped Miter Joint Router Bit might be a good choice as well?

If this works well I may try my hand at using some Baltic Birch on the PC dovetail jig.


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## Stick486 (Jan 4, 2013)

you should find it to work quite well...


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## DesertRatTom (Jul 3, 2012)

Baltic Birch IS ply wood, so is Apple Ply. The other stuff ranges from horrible to just barely passable. Worst of all is the Chinese stuff that is filled in with fine strips of splinter causing bamboo. 

Your joint should look pretty nice. Use a backer board of some sort at the exit end of the cut to help avoid tear out. I generally use a chunk of MDF for a push block/backer board.


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## sreilly (May 22, 2018)

Thanks guys. This will be my first try with Baltic, that's once I get there to pick some up, so now it's way up on my list. I'll get a few 1/2" sheets and one 3/4" to wet my feet and see how things go. I've got a built-in panty that needs to be built. Right now it's a walk-in closet with a upright freezer and a few cheap plastic self standing shelf units. I envision base cabinets with adjustable shelves above with yet again more cabinets above for the need to have but seldom used goods. It can be so much more than it is now and I promised her I would build it.....another month or two of physical therapy and then.


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## TwoSkies57 (Feb 23, 2009)

a good portion of the work piece edge can be cut off at the table saw prior to using the bit on the router table. Extend the life of your cutting edge and save yourself some time. Create an edge on a scrap piece of work, from there you can get a good idea of how much you can remove at the tablesaw.


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## sreilly (May 22, 2018)

Bill I don't follow what you're saying. Typically I mill my wood to the needed size and then cut the boards for the drawers to size before routing any edges. If I'm using the table saw for the bottom shelf slot I may cut that first which helps in remembering which is inside and bottom orientation.


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## Stick486 (Jan 4, 2013)

sreilly said:


> Bill I don't follow what you're saying. Typically I mill my wood to the needed size and then cut the boards for the drawers to size before routing any edges. If I'm using the table saw for the bottom shelf slot I may cut that first which helps in remembering which is inside and bottom orientation.


hog the router cut out on the TS 1st...


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## Biagio (Mar 2, 2013)

TwoSkies57 said:


> a good portion of the work piece edge can be cut off at the table saw prior to using the bit on the router table. Extend the life of your cutting edge and save yourself some time. Create an edge on a scrap piece of work, from there you can get a good idea of how much you can remove at the tablesaw.


Steve what the guys are saying is that you can reduce the load on bit and router by first cutting a 45 degree bevel on your board on the saw, taking care not to cut the full thickness of the board, I.e. leaving a thin facet at the top, to ride against the router fence. Otherwise, you would be pulverizing more than the thickness of your board with the router bit (because of the hypotenuse), with all the dust that flesh is heir to.


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## harrysin (Jan 15, 2007)

Stick486 said:


> hog the router cut out on the TS 1st...


Wouldn't it be more accurate to do that on the router table?


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## sreilly (May 22, 2018)

Biagio said:


> Steve what the guys are saying is that you can reduce the load on bit and router by first cutting a 45 degree bevel on your board on the saw, taking care not to cut the full thickness of the board, I.e. leaving a thin facet at the top, to ride against the router fence. Otherwise, you would be pulverizing more than the thickness of your board with the router bit (because of the hypotenuse), with all the dust that flesh is heir to.


OK now I get it. Sometimes I need a picture, more coffee, my meds, and then some more pictures and coffee. That makes perfect sense and I'll be sure to try that. I agree that make less aggressive cuts can only help. Thanks for spelling it out for me.


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## sreilly (May 22, 2018)

harrysin said:


> Wouldn't it be more accurate to do that on the router table?


I hadn't seen this when I replied to Biagio and now I have a picture to boot. Thanks Harry. Seriously, sometimes I really do need it spelled out and a picture never hurts......


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## Stick486 (Jan 4, 2013)

harrysin said:


> Wouldn't it be more accurate to do that on the router table?


more practical, cheaper, faster and easier on the TS...


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## harrysin (Jan 15, 2007)

What about accuracy Stick, a router bit is accurate and NON-ADJUSTABLE, a table saw is adjustable and therefor can be a whisker out.


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## Stick486 (Jan 4, 2013)

harrysin said:


> What about accuracy Stick, a router bit is accurate and NON-ADJUSTABLE, a table saw is adjustable and therefor can be a whisker out.



all you are doing is hogging away material giving the lock miter bit less to cut..


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## DesertRatTom (Jul 3, 2012)

Use a Wixey digital angle gauge to set the blade at 45 degrees. Use a full kerf blade. Can't get more accurate than that.


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## DesertRatTom (Jul 3, 2012)

I posted this picture a couple of days ago, but in the wrong place. The pix if of the Infinity lock miter jig. Find a safe place to store these in a container, they are easily misplaced. The magnets hold them in place. Those are Infinity bits.


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## Biagio (Mar 2, 2013)

Harry, I’m with Stick on this. Removing the excess stock does not require infinite accuracy - that will be supplied by the lock mitre bit itself. Using a 90 degree V bit will still mean pulverizing all the wood below the diagonal. Easier and quicker with a saw, especially if doing long boards.


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## harrysin (Jan 15, 2007)

I tried the saw once and it didn't leave a perfect point which meant that the lock mitre wasn't perfect so I have never used the saw again for this purpose.


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## Stick486 (Jan 4, 2013)

> perfect point... once...


do you mean toe???
if so, you took off too much...
try it again Harry..


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## harrysin (Jan 15, 2007)

Why should I take a chance when I have a perfect method. In any case you prove my point that because the saw is adjustable, it's possible for the average amateur to be a touch out, but not with my method!


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## DesertRatTom (Jul 3, 2012)

Set up the router bit while the cut is 90, then hog off with the table saw, then return the piece to the router table? The Infinity jig is really accurate, but this is a tricky bit, so you want to test it out on scrap, whether or not you use a saw.

OK Harry, What IS your method. Don't Bogart that information, my friend.


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## DesertRatTom (Jul 3, 2012)

Just posting this for general information. From the Infinity site.


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## harrysin (Jan 15, 2007)

My first lock mitre joints were on this box many years ago and only the lock mitre bit was used and went through the very hard Jarrah with ease. A few other projects were made the same way then I thought that because I hogged out most of the wood with a straight bit when making sliding dovetails I would try a similar method with lock mitres using a 45° bit in the table. This was successful, then I tried the quicker way on the table saw but the joint wasn't perfect so the next project went back to the 45° bit after which I remembered the first joints done only with the lock mitre bit and so every other time I used lock mitre joints that is how I did/do them, it really is far easier with the one bit, I promise you.
Whilst not easy to see, I guarantee that I made it with lock mitre joints, further, the wood was salvaged my my work bench when I first set up business and operated from home in about 1967.
I still have the box.


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## sreilly (May 22, 2018)

Now that's a fine looking box Harry. I'll certainly try several methods but my first box was done with only the bit and it was a box with trays to hold my table saw blades. I made it with 3/4" plywood and the joint indeed hid the bare plywood edges. Made a nice looking shop box. I did order the Infinity setup jigs mainly to save a ton of time and get either dead on or very close on initial setup. I'll report back after I get them and my PT releases me to get back in the shop. I still have very restrictive movements with that new shoulder although it's far better then day one was....seems the first range of motion to return was hand to mouth and then the ability to blow my nose, go figure......itching to do more than walk through the shop.


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## harrysin (Jan 15, 2007)

Thank you for your kind opening words kind sir.


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