Custom router bit

On Monday, July 21, 2014 4:13:23 PM UTC-4, rangerssuck wrote:



Thanks for the input so far, and here are some answers to the questions that were raised: 1) The project is modifying the double-hung windows in my house to work with replacement jamb-liners. These are spring-loaded and are the mechanism from jeld-wen windows, purchased from an outfit in Milwaukee. They used to sell a router bit for the purpose, but they say they can't get the blanks anymore - what they were actually doing is modifying an HSS v-groove cutter that has been discontinued by Sears. I had purchased a bit from them and it's done OK, but then I hit a nail and even though I've resharpened, it's not going to put up with that too many times and I have 25 more windows (50 more grooves) to do. The material I'm cutting is chestnut oak.
I have to do these windows one or two at a time, as the whole job is kind of big and I don't want to disassemble all 25 windows at once.
I have a router table (shop made) set up to do this with the appropriate fences and feather boards, and I'd much rather not have to switch bits for each cut. I imagine that two passes (3/8 straight) and a 45 v-groove with the bearing removed would probably do a great job, but it's either a bit change or a second machine. Also, having standard-size cutters (and carbide, too) would be a major plus.
As for the spade bit being only a 1/4" shank, the router (and bit) that I have now is 1/4" shank, and that's not a problem.
What I would REALLY like is a shaper table to do this, but that's not in the cards now, and would still involve either two passes or a custom cutter.
If I could come up with a way to do a quick-change of the bits (straight & V) that would get them to the same height (perhaps a small collar under one or the other if they're close to begin with the bit-switching wouldn't be so bad. If I have to adjust the height each time, it would be a bitch - my router table doesn't have a lift mechanism.
But back to the original question - is there anything inherently bad about using a modified spade bit in a router? Would it be likely to fly apart at speed if it was slightly off balance? [I've done some design work on controls for 90K RPM motors and seen some spectacular failures]
A paddle bit will twist up as soon as it hits the wood and screw up the job and probably put your eye out.
I assume you are plowing the sashes to fit the patent balance.
From the dimensions and the descriptions of the modified tool this angle is close enough to 45deg to be designed that way.
Don't reinvent the wheel.
Buy a 5/8" 45deg. v-grooving bit. Blunt the end to around 3/16 and cut in two passes. http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bt_sign.html#V-Groove_Anchor
The blunted end will leave the bottom fuzzy but it probably won't make any difference because the sashes probably locate on the bevel before they bottom out on the flat.
Paul K. Dickman
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On Tuesday, July 22, 2014 12:10:02 PM UTC-4, Paul K. Dickman wrote:

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This raises an interesting question (setting aside that the 5/8 is too smal l and I'd have to go to the 3/4" size) : are the dimensions that I have, su pplied by the distributor, correct? They are probably "close enough for gov ernment work" but if you're a carpenter with a ruler that only goes to 16th
I will check the dimensions today.

Why two passes?
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This raises an interesting question (setting aside that the 5/8 is too small and I'd have to go to the 3/4" size) : are the dimensions that I have, supplied by the distributor, correct? They are probably "close enough for government work" but if you're a carpenter with a ruler that only goes to
I will check the dimensions today.

Why two passes?
Because the 5/8 is too small.
Paul K. Dickman
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On Tuesday, July 22, 2014 1:13:45 PM UTC-4, Paul K. Dickman wrote:

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more easily dealt with by going up to the 3/4" bit and lowering it in the r outer table, I think.
BTW, #5419 on http://www.mlcswoodworking.com/shopsite_sc/store/html/smartht ml/pages/bt_sign.html#V-Groove_Anchor is, except for the totally wrong dim ensions, exactly what I need. It cuts a v-groove with a flat bottom.
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snip

more easily dealt with by going up to the 3/4" bit and lowering it in the router table, I think.
BTW, #5419 on http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bt_sign.html#V-Groove_Anchor is, except for the totally wrong dimensions, exactly what I need. It cuts a v-groove with a flat bottom.
Pardon me for snipping, but it replies were staritng to sprawl.
Your are missing my idea. By grinding back the point of the vee bit, you create a flat in the center. The flat won't cut prefectly, but the bevels will do most of the cutting. If that flat is around 3/16 in dia, it will take two passes to cut it to the 3/8 width.
Since they were making these from stock cutters, I strongly suspect that angle is 45deg. These don't come standard in 41.6 deg. It is not inconceivable that they would fully grind a new angle, but it would be a pain in the butt to get the relief right. I think it is more likely that they just ground a couple of flutes on the end to bottom cut the flat.
Paul K. Dickman
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How about this:
- 1 pass through the router with a 3/8" straight cutter - 2 passes through the table saw with the blade tilted to your angle (stock turned end-to-end for 2nd pass)
If grove is not centered on the stock, the 2nd saw pass would require moving the fence. Or better, having an offset piece clamped to the fence.
No bit changes, or set up changes except for the possible saw fence offset.
Bob
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On 7/22/2014 12:10 PM, Bob Engelhardt wrote:

oh, wait ... your angle is more than 45 degrees (90 - 41-1/2 = 48-1/2) and your table saw blade might not tilt more than 45 (mine doesn't). You could get around this by lifting the fence side of the stock, but that's getting kind of ugly.
Still, overall, it's fast, straight forward, cheap, simple, ...
Bob
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On Tuesday, July 22, 2014 12:21:24 PM UTC-4, Bob Engelhardt wrote:

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king that I should do some actual measuring rather than going by the sketch from the supplier. I will do so later today.
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On Tuesday, July 22, 2014 1:41:01 PM UTC, rangerssuck wrote:

fences and feather boards, and I'd much rather not have to switch bits for each cut. I imagine that two passes (3/8 straight) and a 45 v-groove with t he bearing removed would probably do a great job, but it's either a bit cha nge or a second machine. Also, having standard-size cutters (and carbide, t oo) would be a major plus.

You said the magic words. Second machine. Either a used one off craigsli st or one from Harbor Freight . They have a trim rounter for $29.95 and wi th just a little effort you can find a 25% off coupon. Sometimes on sale f or about $20. Set the second router up with the 3/8 straight and leave it set up until yo u have done all the windows.
http://www.harborfreight.com/1-4-quarter-inch-trim-router-44914.html
Dan
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On Tue, 22 Jul 2014 06:41:01 -0700 (PDT), rangerssuck


I would use a shaper head and knives on a table or radial arm saw. Regrind the knives to the desired shape. http://www.sears.com/search=shaper%20cutters?catalogId 605&storeId153&levels=Tools_Hand+Tools_Cutters+%26+Snips&autoRedirect=true&viewItemsP&redirectTypeT_REC&prop17=shaper%20cutters
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