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troubleshooting my biscuit router bit

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Forum topic by Spacehog posted 01-06-2016 07:14 PM 586 views 0 times favorited 14 replies Add to Favorites Watch
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Spacehog

65 posts in 985 days


01-06-2016 07:14 PM

Topic tags/keywords: router biscuit jointer

Ahoy everyone, I have a problem that I just cannot figure out, so I thought I’d rely on your collective knowledge. I recently bought a biscuit router bit for a project and it has been giving me a strange problem. I got it all installed fine, and had it in my router table and I (thankfully) decided to give it a few test cuts on a piece of scrap before committing my real piece. When I made the cut on the end grain, I noticed that the cut seemed to drop from where it went in at the time it came out. I double checked to make sure that the bit was securely fastened in the collet, and everything seemed to be alright. When I tried another test cut the bit started to cut at the correct height again, but ended lower than it began. When I tried cutting with the grain, the bit performed perfectly. So I tried it on another piece on the end grain and the same bad thing happened where the cut seemed to drift lower as the cut progressed. But it only happens when I’m cutting end grain. Also, I’m sure that the bit itself isn’t actually dropping because the new cut always starts at the correct height. I tried to include some pictures, but apparently they are too big. I’m going to see if I can shrink them somehow and get them posted so that you can see what I’m talking about.

For the life of me I cannot think of a reason why this would happen only on end grain cuts. The scrap piece I was using was reasonably squared and it was pine, so it shouldn’t have been too tough on the router. Thanks in advance. I’ll try to get some pictures here soon…

-- Whatever your hand finds to do, do it with all your might...


14 replies so far

View ChrisK's profile

ChrisK

1809 posts in 2541 days


#1 posted 01-06-2016 07:47 PM

The wood may be lifting off the table, try putting a finger board over the bit so the wood cannot lift. The lift can be caused by the bit following the end grain.

-- Chris K

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Spacehog

65 posts in 985 days


#2 posted 01-06-2016 08:17 PM

I thought that too ChrisK, but I’m pretty sure that I’ve taken the correct precautions. I had the featherboards, almost on top of the piece, and they were set to the thickness of the board, so I can’t see how it would lift if that circumstance. Certainly it couldn’t lift enough to account for the drift I was seeing.

-- Whatever your hand finds to do, do it with all your might...

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Spacehog

65 posts in 985 days


#3 posted 01-06-2016 09:11 PM

https://www.facebook.com/photo.php?fbid=10208544125660388&l=15873f8e61

Ok, hopefully this time the pictures will post. The cut started on the right where my thumb was and then drifted down as it moved towards the side with my index finger. This only happened when cutting end grain though. The other picture shows how it cut properly when I was cutting with the grain.

https://www.facebook.com/photo.php?fbid=10208544125740390&l=37ef5fe311

-- Whatever your hand finds to do, do it with all your might...

View pintodeluxe's profile

pintodeluxe

4852 posts in 2273 days


#4 posted 01-06-2016 09:32 PM

Sounds like a router or router table problem…
Try tightening the router in the router base. Also check that the screws securing the router plate to the router table are secure.
Is this a benchtop router table or full-size?
Benchtops are not always very accurate.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

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Spacehog

65 posts in 985 days


#5 posted 01-06-2016 09:35 PM

Thanks for the replies. I’ll see if I can check out the connection of the router and the router table itself. They’re both Bosch, so I think that they ought to be fairly reliable. Also I’m still mystified as to why the drift would only occur when cutting end grain. It seems like some sort of black magic I tell ya! Haha.

-- Whatever your hand finds to do, do it with all your might...

View Kazooman's profile

Kazooman

623 posts in 1412 days


#6 posted 01-06-2016 10:29 PM

I don’t know why you are having the problem, but I am curious about how you are using the bit. If I understand the term “biscuit router bit” I imagine it is intended to be used like a biscuit jointer. That is a single plunge cut to make the curved recess for the biscuit. Why are you trying to rout a long groove with the bit?

View wood2woodknot's profile

wood2woodknot

49 posts in 1433 days


#7 posted 01-07-2016 03:44 AM

Do you have any play (maybe only intermittently) in your router shaft? Is it shifting from pressure against it as you cut? Across the grain creates more pressure on the shaft than with the grain cuts. Side pressure against the shaft would cause the shaft to tilt ever so slightly and lower the depth of the cutting edge. I have trouble sometimes with my Craftsman that way. If my depth of cut changes I know the shaft has shifted out of vertical.

-- ajh

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Spacehog

65 posts in 985 days


#8 posted 01-07-2016 04:27 AM

I am using the “biscuit router bit” to cut a groove for a spline.

The spline that I need will be to shore up a miter joint though which is why I was testing it on an end grain cut. My bit has a 1/2” shank which I hope would reduce any play it might have. I think that my problem might be that I had unbuckled the router engine to adjust the height and I thought I had buckled it back before cutting, but now I’m not so sure. The router I have kind of clicks into a spot if you want to adjust the height. I thought that I had re-buckled it before cutting, but it’s possible that I did not. If it was unbuckled that would account for some tilt when pushing the piece against the bit. I’m going to give it another couple of cuts when I get back to my shop.

-- Whatever your hand finds to do, do it with all your might...

View TheFridge's profile

TheFridge

5764 posts in 946 days


#9 posted 01-07-2016 05:30 AM

Light cuts.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View Karamba's profile

Karamba

116 posts in 396 days


#10 posted 01-07-2016 05:33 AM

Looks like you have a twisted board.

View pintodeluxe's profile

pintodeluxe

4852 posts in 2273 days


#11 posted 01-07-2016 06:30 AM

I think that my problem might be that I had unbuckled the router engine to adjust the height and I thought I had buckled it back before cutting, but now I m not so sure. The router I have kind of clicks into a spot if you want to adjust the height. I thought that I had re-buckled it before cutting, but it s possible that I did not.

- Spacehog

Bingo. That is just the sort of thing that would cause your problem. Routing end grain causes a little more vibration, which would explain why your long grain cuts looked normal. Check it out and let us know.
You are using the router bit for one of its intended purposes… slot cutting. Nothing wrong with that. When the bit cuts a 5/32” slot they usually call it a biscuit slot cutter because it is incidentally the right size for biscuits.
Good luck with it.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View rwe2156's profile

rwe2156

2190 posts in 941 days


#12 posted 01-07-2016 12:56 PM

Yeah, if not locked down that happens.

Nothing to do with your question, but you should consider cutting slots on your TS.
I think you’ll find that is a faster, safer, better way to go.

-- Everything is a prototype thats why its one of a kind!!

View Spacehog's profile

Spacehog

65 posts in 985 days


#13 posted 01-07-2016 07:40 PM

Alright, it looks like I’ve got it all sorted out now, thanks so much for everyone’s input!

One last thing, I certainly see the logic in using a TS, but I just got this router table for Christmas, so I wanted to familiarize myself with it for this project.

-- Whatever your hand finds to do, do it with all your might...

View 716's profile

716

502 posts in 376 days


#14 posted 01-07-2016 08:10 PM


Nothing to do with your question, but you should consider cutting slots on your TS.
I think you ll find that is a faster, safer, better way to go.
- rwe2156

Are you saying that laying a board flat on the router table and running it over an 1.5” bit is less safe than doing the same vertically on a table saw with a 10” blade ?
Also about faster. No way you can make a biscuit slot faster on a table saw than on a router table with a specialized 5/32 bit. I even do not go into the precision.

-- It's nice!

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