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New Mortiser -- Problem with chisel/bit

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Forum topic by felkadelic posted 04-01-2012 12:56 AM 2214 views 0 times favorited 19 replies Add to Favorites Watch
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felkadelic

212 posts in 2005 days


04-01-2012 12:56 AM

Just picked up a Woodriver mortiser today on sale at Woodcraft. Got it home and set it up, and ran into a problem.

On the two bits/chisels that I tried (3/8 and 5/16, I believe), the diameter of the auger bit seemed to be slightly greater than the area of the chisel. So when I plunged into the workpiece, I end up with a hole that is square at the corner of the chisel, but bows out on each side. (Hopefully this description makes sense—if not I’ll try to get back out to the shop tonight and snap a picture)

Have I set up something wrong? I read both the Woodriver manual as well as the more detailed Steel City manual, and watched The Wood Whisperer’s mortiser setup guide, but didn’t see this addressed.

I’m leaning toward the stock chisels/bits just being crap. I actually broke the tip off of the 1/4” auger bit on the second plunge into a piece of pine—I’m waiting to hear back from Woodcraft on a replacement for that.

If anyone has any thoughts/suggestions, I’m all ears.


19 replies so far

View spunwood's profile

spunwood

1198 posts in 2301 days


#1 posted 04-01-2012 01:05 AM

I had this problem. The big thing is to make sure that the chisel and auger bit height relationship is right on. Try this video:

http://blip.tv/the-wood-whisperer/episode-5334237

With all that said…I still haven’t got my craftsman mortiser to just right. So I am selling it and going to learn to do it by hand.

-- I came, I was conquered, I was born again. ἵνα ὦσιν ἓν

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felkadelic

212 posts in 2005 days


#2 posted 04-01-2012 01:09 AM

As I mentioned, I’ve watched that video (and have set up my machine accordingly I believe). I guess what I don’t understand is why the height relationship should make a difference in this case. Assuming the chisel and the bit are moving parallel to each other, why should there be any impact of bit height on the pattern of the cut?

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spunwood

1198 posts in 2301 days


#3 posted 04-01-2012 01:19 AM

I think the issue is that a bit may ‘flex’ during drilling and in ratio to the kind of wood (resistance) encountered…But I never could get a single cut to be perfect (not meaning rough inside, but meaning no lip or rounding out of outer sides.

-- I came, I was conquered, I was born again. ἵνα ὦσιν ἓν

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JJohnston

1614 posts in 2757 days


#4 posted 04-01-2012 01:26 AM

I’m no help here, but I’m stumped – how can the drill make a hole bigger than the chisel, when it’s inside the chisel?

-- "A man may conduct himself well in both adversity and good fortune, but if you want to test his character, give him power." - Abraham Lincoln

View gfadvm's profile

gfadvm

14940 posts in 2155 days


#5 posted 04-01-2012 02:35 AM

I’m guessing that you need to extend the drill bit a little further past your chisel as this will improve chip clearance and cut quality (at least it did for my Jet mortiser).

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

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felkadelic

212 posts in 2005 days


#6 posted 04-01-2012 03:28 AM

I think spunwood might be onto something. I’ll try gfadvm’s suggestion and might try honing the cutting edge of the auger bit. Will post results in case someone has a similar problem in the future.

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spunwood

1198 posts in 2301 days


#7 posted 04-02-2012 11:40 PM

any luck?

-- I came, I was conquered, I was born again. ἵνα ὦσιν ἓν

View SnowyRiver's profile

SnowyRiver

51452 posts in 2946 days


#8 posted 04-03-2012 12:38 AM

I’m with JJohnston…not sure how you could get a mortise hole bigger or bowed out if the chisel is square and the auger is inside the chisel. The auger tip should be protruding from the bottom of the chisel just slightly and the auger itself just about even with the bottom of the chisel.

-- Wayne - Plymouth MN

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felkadelic

212 posts in 2005 days


#9 posted 04-04-2012 02:29 AM

Increasing the gap between bit and chisel helped slightly, but there’s still a definite curve to the sides of the mortises. I was somewhat unhappy with Woodcraft’s tech’s response, which was basically that this problem is unavoidable. I’m strongly debating trying to return the mortiser, and either save money for a high-end unit (and hope that I don’t have the same problems), or just resort to hand-chopping my mortises in the future.

I’m going to try two more things before trying to return, though. I’m going to hone the cutting edge of the auger as well as I can, and I’m going to try drilling out the majority of the mortise waste with a forstner bit before hand—perhaps having less stress on the auger bit will help my situation.

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SnowyRiver

51452 posts in 2946 days


#10 posted 04-04-2012 03:08 AM

Is the side of the chisel bowed? I am trying to figure out how the hole can be bowed on the sides if the chisel is square. I dont think I would do to much to the chisels or auger if you are going to return it. They might tell you that you did something to it. If you have to drill out some of the hole with a forstner bit first, you kind of defeat the purpose of the machine. I think I would take it back and buy a good one.

-- Wayne - Plymouth MN

View Grandpa's profile

Grandpa

3256 posts in 2141 days


#11 posted 04-04-2012 03:12 AM

The bit is flexing and reaching out past the edge of the chisel. sounds like you have the bit set too far out. Put the chisel in the machine and space it down with a nickel for a spacer. Put the bit in the chisel and into the chuck. push it up as far as you can into the chisel and tighten it there. Go back to the chisel and move it up to the shoulder and it should be about right. Try that and see what happens.

View felkadelic's profile

felkadelic

212 posts in 2005 days


#12 posted 04-05-2012 04:50 AM

Just an update for anyone interested. I tried minimizing the gap between bit and chisel (by using no spacer when setting the gap) and got my best results yet. It’s still not perfect, but it’s definitely satisfactory for most mortises (except probably not for through mortises)

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spunwood

1198 posts in 2301 days


#13 posted 04-06-2012 01:25 AM

Thanks for letting us know. I had the same results. Are we expecting too much? Maybe for the quality of machine we purchased.

-- I came, I was conquered, I was born again. ἵνα ὦσιν ἓν

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felkadelic

212 posts in 2005 days


#14 posted 04-07-2012 04:48 AM

As far as I’m concerned, the problem isn’t with the mortiser itself but with the chisels/bits.

In messing around with the machine a bit tonight, I discovered that my 3/8” chisel is roughly 1/32” out of square, over that 3/8” span! Unbelievably poor machining. I’m hoping Woodcraft will send me a replacement (my replacement 1/4” auger bit is already on the way).

View Phil68's profile

Phil68

16 posts in 1684 days


#15 posted 04-29-2012 03:45 AM

Joined Lumberjocks tonight. I was searching for a solution to the same problem your having. I just picked up the Woodriver from Woodcraft last week. The holes I’m boring are square on corners and rounded on edges too. Today I was working on a solution again. Here’s what I found… If the auger bit is fully seated in the chisel, the spur, which is larger than the i.d. of the chisel shaft, actually does protrude slightly passed the sides of the chisel. I checked this by placing a square on the edge of the chisel perpendicular to the ejection port, but down by the cutting edge of the chisel. I then rotated the drill bit inside the chisel and could obviously hear an see the spur, when passing by the arch in the side of the chisel, was scraping on the square. In my case, It’s gotta be bad machining on the bit/chisel. I’m calling woodcraft tommorrow to see if they’ll replace them.

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