Monday, July 26, 2010

Milling Dog Holes And Other Questions

Here's another round of customer questions that we thought we'd share.

Q: I have been reviewing my bench plans and I had a question. Do you have a suggestion on how to produce the jig you have made for routing the dogholes? Is this jig ever going to be made for sale? Also is it a bad idea to create the recess for the tailvise during lamination? Geez more then one question sorry, when are the V2 tailvise instructions going to be maid available?

A: Below are some pics and notes about the jig we use for routing dog holes. And no, we won't be making one for sale. You can make on in your shop in about 30 minutes. It's a good idea to create the tail vise cavity during the top build. Or at least most it. If you can't easily make it spot on while building, just "leave out" most of it, then take it to final dimensions with a plunge router (or chisel and mallet). The V.2 Tail Vise instructions are almost done and we will hopefully post them this week. Stay tuned to the blog for this announcement.















The dog holes are routed into the side of the dog hole strip before it is laminated to the rest of the top. The are routed into the "back side" of the strip, that's why they are leaning the "wrong" way in the above picture. To make the jig, layout the dog hole actual size on a piece of 1/2" plywood, but shift it down 3/4" from the top edge of the ply (this is to account for the fence thickness). Cut the dog hole "out" from the plywood. I use a miter saw to establish the 2-degree angle cuts, then followup with the band saw to cut the step into the left side of the jig where the head of the dog will rest. Now separate the halves the width of the dog hole and screw a 3/4" x 1-1/4" hardwood fence to the underside of the jig, flush the back edge. This will position the dog hole correctly from the top of the dog strip. Make the fence a bit longer than the entire jig so you have something for the clamps to hold onto.




















Rout the dog hole with a pattern (top-bearing) bit. You'll cut into the fence a bit at the top, just make sure you don't cut completely through, or you'll ruin the fence. You'll have to make the cut at full depth for the bearing to engage. If you have two routers you can make the cut in a couple passes. Fit the first router with a template guide and spiral upcut bit and make a hogging cut (I did this in the above pic--there's about 1/8" of waste remaining) leaving just a little waste to be removed with the pattern bit. This eases wear on the pattern bit and reduces burning too. Keep in mind that at the top left corner and the bottom right corner your router will want to blow out grain as it exits the cut. I move the bit almost to the corner, then swing out and back to make a climb cut to reduce blowout. You can also scribe these areas deeply with a knife before routing to further eliminate blowout. But if you're careful and attentive (and confident!) with the router, the climb cut just at the end is sufficient.

Once you've done one, reposition the jig and do the rest. Be careful with the dog strip once you've routed all the holes. It will still be heavy, but fragile. It will want to flop around. Also, when you glue the dog strip to the rest of the top, make sure you put glue on the dog strip only! And don't go overboard here. Cleaning glue out of dog holes is no fun. Well, actually it can be with a new product we're working on. But more about that some other time.
















Q: I joyously received my vise last week and sat down to install it today and it appears I have a left handed version. I'm skeptical that I ordered it wrong but that's not out of the realm of possibility. I'm attaching a picture (see below) to make sure I'm not crazy. Maybe this just got put in the wrong box?

A: Pictured is a right-hand vise. For shipping purposes we install the sliding plate assembly on the screw in the reverse position. Just unthread it from the screw, flip it around, then thread it on from the other side of the nut. That's it.




















Q: Hello, I am just about to get started on my Roubo bench. I have been reading and watching everything I can about the project. I am sure as I move forward there will be many questions for me to find answers to, but one thing looks off to my eye. Is there a reason that the Gap Stop is not the same length as the bench top?

A: Thanks for the (not dumb) question. Here's the no-nonsense reason the gap stop is shorter than the workbench. When I built the prototype those were the longest boards I had on hand. I quickly realized that a longer one wasn't necessary. If you want it to reach the end of one of the tops (for example, when crosscutting), just slide it down. You can also make the gap stop the entire length if you want, but if you build it to the plans, you'll save some weight and that makes it easier to lift out and reposition if you like. The gap stop in the plans is just a starting point. You can make your's to suit your work.

8 comments:

  1. Do not feel bad I thought I had the wrong tail vice as well, Amazing how the feeling of elation after waiting 6 weeks and finally recieving wagon vise can change.

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  2. Any luck on the new instruction?

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  3. Hi. I've looked for dimensions of the dog strip and can't find them. How big are the cut outs? I saw the design for the dogs on another page.(http://benchcrafted.blogspot.com/2010/06/talking-bench-dogs.html) Are these cut outs made to fit those? How far apart do the cut outs need to be from each other, or does it matter? I'm assuming there are two strips, so how far do the strips need to be apart?

    Can "square" dog holes be cut into an existing top?

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  4. Sure, you can make the dog holes any size you like. The design in that other post is size we most commonly use. But it's not set in stone. The closer you space them, the less you'll have to crank your tail vise. 3"-5" is a good number. Not sure what you mean by "strips". You can chisel square dog holes into an existing top with great difficulty. It's not worth the effort. Go with round dogs.

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  5. Thanks for the response. "Dog strips" was taken from your statement on your blog: "The dog holes are routed into the side of the dog hole strip before it is laminated to the rest of the top"

    I think I was wondering how far apart those strips should be 12" 18"? I think my table is presently 32 inches wide, so I figured they would be 18" or so apart, but didn't know if it mattered.

    As far as the round holes were concerned, I was thinking about making a new top rather than having round holes. I'm sure there's nothing wrong with round holes, but I would figure less denting would happen with more surface touching my project with square dogs. Just my thinking. Probably wouldn't put that much pressure on them anyway. But also, aren't the round dogs harder to make? As for square holes, couldn't I just use a jig saw? Or reciprocating saw? Does the hole have to have that 2 degree slant? I've never made them or used them, but I can see how they would be handy. So, I'm asking all this before I get started. Thanks again,
    Andy

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  6. Creating a second dog hole row is mostly a waste of time. You don't really need the second row.

    If you use round dogs, you make a flat where they grip the workpiece.

    If you come up with an efficient, accurate way of cutting square dog holes with a jig saw, or (even more impressive) a sawzall, we're all ears.

    Judging by your question, I would recommend you read three books. The Workbench Book by Scott Landis, and the two bench books available from Lost Art Press. http://www.lostartpress.com/catalog/cf1f3915-00f4-4498-b9ba-2ca623c4631b.aspx

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  7. Okay, thanks. Some may take offense at your recommendation. I, on the other hand, bought the Landis book (already like it) and plan to buy the The Workbench Design Book By Christopher Schwarz.

    I laughed at your "we're all ears" comment. It was just wishful thinking. Even though I am pretty accurate in my power hand-tool cutting, I'm not foolish. Ignorant maybe, but not foolish. ;)

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