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Forum topic by Absinthe posted 11-07-2011 04:47 PM 3924 views 0 times favorited 17 replies Add to Favorites Watch
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Absinthe

84 posts in 1991 days


11-07-2011 04:47 PM

I have said it before and will say it again, the router is my least favorite tools and most feared period. If something will go wrong on a project, it will invariably go wrong with the router. (Not that other things don’t go wrong, but if the router is involved, it will have some kind of grief associated with it.

I do have a Dewalt 621 plunge that I picked up a year or two ago and have only started to play with it. Perhaps I will have better luck with the more powerful, and seemingly better built DeWalt. I do have a small veritas or vermont american (can’t remember which) router table that the craftsman fits into rather well. It has too small of a top to be all that useful, but I am about to relegate the Craftsman to a permanent home in that table.

I have been trying to build something that involved using a piece of a Sonotube (the cardboard forms used for pouring concrete) and plugging the ends with circles cut from plywood.

I determined the ID of the tube and wanted to make the circle pretty much exactly that, figuring that I could sand down to fit snugly from there. Rather than adding to the complexity of the project by building my own circle cutting jig I went to $ears and bought the one they sell. Without getting into a product review let me say that it appears to be sufficient, but I am not thrilled with the fact that the registration pin is a roll pin, and the recommended pilot hole for it is such that it is difficult to remove the finished cut piece. It is what it is, and I see no reason for it not to function as advertised.

The router motor I am using is a non-plunge Craftsman that I have had for more years than I care to remember. It is 1 HP and just refuses to die. So it is the first one I go for especially when I buy a craftsman accessory, since I know the hole pattern will match up.

Obviously a 1/4” straight bit will not hog through 3/4” plywood, as a matter of fact, I was taking 3,4 or even more passes. This is a pita with a manually adjustable (not plunge) router. (I did try a spiral bit, but the straight bit, contrary to all the advice I was given, worked better)

Anyway, as carefully as I could measure, there was always a contradiction in size, with no really good reason that I could tell. For example, once cut, I would turn the router upside down and have to use 2 screw drivers to pry off the cut piece. It was immediately obvious to my eye that there was a good 1/16 to 1/8 or even more between the exposed bit and the cut edge. I even unplugged it and rotated the bit by hand and it comes nowhere close to the cut piece. I am not certain if this is due to the bit hacking out huge chunks yet leaving a nice smooth edge? It didn’t sound logical. The adjustment screw was very tight so there was no slippage of the jig, and the registration pin was nearly as tight in the hole as if I nailed it in with a hammer.

After micro-adjusting things slightly larger and wasting lots and lots of 3/4” plywood, I came up with a few acceptable circles (hopefully gorilla glue will make up for the slight gaps. I wanted one more and began the setup 1 more time. No sooner did the router bit hit the plywood that I heard it literally explode. Not the wood, the bit. I have the piece that was left in the collet but there was not another piece of it large enough to pickup left to be found! I have never seen such a thing, and was glad my face was nowhere near the viewing area when it went lest I find out if the UL rating on my safety glasses is actually accurate.

I am now wondering if the bit may have been bad from the start and was somehow doing some kind of wobble action throughout. I replaced it today with a brand new Bosch with attached carbide rather than a solid carbide bit. Hopefully my results will get better from here.

Is there anyone out there that just LOVES using their hand held router, that can help convert me? Anyone have any ideas for projects that use one or a bunch of approximately 7-1/2” to 8” plywood and/or mdf circles? Approximate being the key word. I bought some smooth rod and threaded inserts and set screws to make an edge guide for the DW621, perhaps even a circle cutter. Help me stop cringing whenever a project calls for a router :S

-- Absinthe


17 replies so far

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Absinthe

84 posts in 1991 days


#1 posted 11-07-2011 08:57 PM

There was no slippage of the jig. I cut quite a number of circles that were each the same size as the other, just not the measured size of the distance from registration to bit blade. I am going with the bit being wonky. I will find out tonight with a brand new bit.

-- Absinthe

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taxque

8 posts in 2221 days


#2 posted 11-07-2011 09:01 PM

Hopefully you were making your cut in multiple passes and not one pass. In addition you can always use a smaller circle itself as a template with a bearing or bushing guided bit to give the right off-set for the correct finished diameter. This can also be done using and oversized cutout template and routing inside the cutout edge. I suspect that your router bit diameter may have been off – always good to use a micrometer on it to make sure it is correct. When using a circle cutter it is alway a good idea to swing an arc on a test piecee and see what your diameter is – very rarely will it start of correct and end up under size. I would sugget a book by the name of ” Router Magic” – it has a lot of helpful hints on router use both handheld and in a table. There are also forums specifically dedicated to the router you may want to join one of those as well.

-- G Heard

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knotscott

7207 posts in 2835 days


#3 posted 11-07-2011 09:14 PM

I think a router is the greatest thing to come along since sliced bread. Once you get used to them, there’s almost no limit to what you can use them for.

For cutting shapes (and small circles) I like to use a template with a pattern bit….cut it close with a jig saw, then just clean it up with the router bit. 1/2” shank bits are a lot more robust than 1/4”. I usually only use a circle jig for large circles (like tables ) and arcs.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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Absinthe

84 posts in 1991 days


#4 posted 11-07-2011 09:16 PM

Yes, I was using multiple passes, sometimes as many as 7 or 8.

The fact that the bit exploded, and sheared right across suggests to me that it was either cracked or bent at the attachment point. It finally gave way. I purchased a brand new name brand bit this morning and will try that to see if it cuts nice. If it does, I will be going with the bit being a baddie rather than anything else.

Just to note, this bit was part of a set that I bought at Lowes a while back with a whole buttload of bits of all different profiles in a little double door cabinet. I am leaning towards some poor quality bit and this being the results of it.

However, if this nice new brand name bit behaves exactly the same, hopefully without the explosive disintegration, then I will go for the router or jig being at fault. Of course if I just build my edge guide/circle cutter for the other router I can then debunk whether $ears’ jig is bad. Somewhere something has to be bad, I am leaning towards the exploding bit though :)

-- Absinthe

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taxque

8 posts in 2221 days


#5 posted 11-07-2011 09:20 PM

Absinthe

Reading your post again I see that you did use multiple passes. Another common occurance, esp with older routers is that the base may not be centered concentrically about the collet/bit. They have centering pins that can be used specifically to center-align the base to the collet/bit. Some router bases have oversized mounting holes that can allow the base to be shifted off center by as much as 1/8 inch easily. In addtion it is essential to make sure the base and any jig attachment screws are tightened properly so that they don’t shift during use.

-- G Heard

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Absinthe

84 posts in 1991 days


#6 posted 11-07-2011 09:20 PM

I don’t think either of my routers will take a 1/2” shank, unless the DW621 does..

I have seen suggestions of following templates, but that gives me the chicken vs egg problem. :)

What do you consider a “small” vs “large” circle? I am cutting 12” and 8” and tonight it will probably be 10” the really small ones 2” I am using a hole saw for.

-- Absinthe

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Absinthe

84 posts in 1991 days


#7 posted 11-07-2011 09:25 PM

taxque -

This is a round based router. However, you remove the base and install this:

http://www.sears.com/shc/s/p_10153_12605_00925179000P?mv=rr

I am not sure the centering of the router bit would matter since we are speaking of an essentially rotating wood around a point which will have a distance from the bit.

-- Absinthe

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Absinthe

84 posts in 1991 days


#8 posted 11-07-2011 09:37 PM

taxque—

I think what is being missed is that I was able to set it up and cut multiple circles, each the same size as the other, and each one of them actually round. Where the inaccuracy was coming in was based on my expected distance from the registration pin and the edge of the router bit.

I would think of my results as something similar to when your tablesaw blade is not parallel to your rip fence and you wonder why the ripped boards are not the same width as you expect. (Ask me how I learned that one :))

I think the router bit was actually wobbling, it wouldn’t have to wobble much to have this kind of behavior, and I doubt it would have to wobble too much to explode either. I think my collet is ok, I am leaning towards a defect in the actual bit.

-- Absinthe

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taxque

8 posts in 2221 days


#9 posted 11-07-2011 09:52 PM

Certainly appears that the router could be offset in the jig – but that should not come into play for a circle as once it is set the distance from center does not change, the effective diameter of the circle is from the mouting pin to the inside edge of the router bit, the effective diameter of the the hole left in the stock is from the mouting pin to the outside edge of the router bit.

The 621 will take a 1/2” shank. I would consider 8” or 12” small to medium circles. I did a 5’ round table top that I would consider large.

I think it has to be the bit as well – may have been slightly oversized. Let us know what hapens with the new bit.

-- G Heard

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Absinthe

84 posts in 1991 days


#10 posted 11-07-2011 10:38 PM

So how would you cut an 8” circle? Or more importantly a 7-29/32 circle? or some other random small circle?

-- Absinthe

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404 - Not Found

2544 posts in 2429 days


#11 posted 11-07-2011 10:48 PM

Here’s a little golfing adage for you: “Confidence breeds success”

Don’t fear your router, if you think you’re going to mess up with it you probably will.

Dust off the DW621 – it is a Prince amongst routers, and put your circle cutting attachment in a drawer. For your circle cutting project you need only a piece of hardboard, a ruler and a screw.

You can use any size bottom cutting bit for this, it doesn’t have to be a 1/4” cutter – they are all weak where they meet the shank. I’ve had plenty of bits break before but never experienced one shooting across the room (though that’s not to say it couldn’t happen)

take multiple shallow passes like you did before and everything should be ok.

The router is one tool I couldn’t live without.

Hope it works for you.

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Absinthe

84 posts in 1991 days


#12 posted 11-07-2011 10:52 PM

Every time I see this jig it has this tapered icecream cone shape, why is that? Obviously a rectangle would work just as well, but every one I see even the expensive clear ones at the store are shaped like this, why?

I have some Masonite, I may just give it a try.

-- Absinthe

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taxque

8 posts in 2221 days


#13 posted 11-07-2011 11:07 PM

I don’t know why they are tear drop shaped. I have a Lewin and it is indeed shaped like that. The ones I made myself were rectanges and worked just fine. I think Jasper makes a thicker acrylic square one but it is adajustable only to 1/16 or 1/4 increments. Routerforums.com shows some rectangular DIY designs. Agaiin I would highly recommend Router Magic

-- G Heard

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404 - Not Found

2544 posts in 2429 days


#14 posted 11-07-2011 11:13 PM

I was going to add as a postscript… ‘It doesn’t have to be ice cream cone shaped’. However, I neglected to do so.

I would imagine that the shop bought ones are that shape to save on raw materials in whatever sweat shop they are made in.

Collets available for the 621 are 6mm, 1/4”, 8mm and 3/8”

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Lee Barker

2170 posts in 2310 days


#15 posted 11-08-2011 12:12 AM

I make my own jigs out of clear acrylic, 1/4 thick. It is sooooo handy to be able to see through it. It has numerous holes on the pivot end, so I just load it onto the router base and set the cutting edge about where I want it and then see of there is an existing hole in the vicinity. If not, I mark and drill a new one, anywhere on the rectangle so long as the cutting edge of the bit iis on the axis.

I use a 3/16 bolt for the pin. Smooth shaft; the threaded part is cut off.

Kindly,

Lee

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

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