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Forum topic by Tennwood posted 08-11-2017 01:21 PM 286 views 0 times favorited 6 replies Add to Favorites Watch
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Tennwood

110 posts in 2898 days


08-11-2017 01:21 PM

Topic tags/keywords: mortiser

First I must say that I have never owned or used a mortiser before so this is all new to me.
I purchased a Rikon mortiser recently and have begun to try it out. I got the mortiser because I want to make through mortises with clean sharp edges. Until now I have used a router (and occasionally an drill press and chisel) for my mortises. It came with 4 bits/chisels. I cleaned up and sharpened the bits/chisels and set up the machine per a Fine Woodworking article by Roland Johnson. One problem (among others issues I have with the machine) is that I am getting rounded edges on the cuts. It is like the bit is rounding out the hole before the chisel makes its cut. I adjusted the chisel/bit clearance at several different settings and get the same result.
I don’t know if this is an issue with the set up, the machine or with the chisel/bits that came with it.
This isn’t the only problem I am having with the machine but is the most glaring at the moment. Once I get more familiar with it, I will do a review. Right now it would struggle getting two and a half stars.
I would appreciate any ideas or lessons here.

Thanks as always.
Jim

-- Jim, SE Tennessee, "Don't spare the kindling Dear, we have plenty"


6 replies so far

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builtinbkyn

1498 posts in 657 days


#1 posted 08-11-2017 01:27 PM

Hi Jim. I had similar issues with a used Shop Fox mortiser I picked up. Check you’r bits again. Particularly the inside bore of the chisel. The bits I had were very poorly machined on the inside, preventing the chips from ejecting properly. I had to clean them up with a file and sandpaper. Then I applied some wax and this helped tremendously. Also, as you already know, setting the drill inside the chisel so that there’s some clearance is important. There are all sorts of recommendations on the net for how to go about doing it. My mortiser is now ballast for my bench as I don’t really use it because it seemed more trouble than it was worth. I’m sure a really god full size machine would do a much better job than my benchtop model.

-- Bill, Yo!......in Brooklyn :)

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AandCstyle

2796 posts in 1974 days


#2 posted 08-11-2017 08:58 PM

Jim, I can’t imagine how you can get rounded edges unless the chisel is entering the stock at an angle. Maybe a picture or two would help. Sorry I don’t have an answer for you.

-- Art

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builtinbkyn

1498 posts in 657 days


#3 posted 08-11-2017 09:15 PM



Jim, I can t imagine how you can get rounded edges unless the chisel is entering the stock at an angle. Maybe a picture or two would help. Sorry I don t have an answer for you.

- AandCstyle


Art, it sounds like the bit is crushing the fibers at the entry of the cut. So he’s not getting a crisp line on the face. I had the same issue. The bits “seemed” sharp, but the hollow inside the chisel was very rough, preventing the evacuation of chips and the cutting edge wasn’t really sharp because of the poor milling on the inside edge of the chisel. That is crushing the fibers before they’re cut, leaving a rounded over edge or line. Well I’m guessing that’s what he was referring to :)

-- Bill, Yo!......in Brooklyn :)

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AandCstyle

2796 posts in 1974 days


#4 posted 08-12-2017 10:27 PM

Bill, if your diagnosis is correct, maybe these cone sharpeners would help.

-- Art

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builtinbkyn

1498 posts in 657 days


#5 posted 08-12-2017 11:30 PM



Bill, if your diagnosis is correct, maybe these cone sharpeners would help.

- AandCstyle


Well the OP hasn’t gotten back to us so we really don’t know lol I thought about purchasing those cone sharpeners back when I was dealing with this, but careful filing/sanding helped. I think I also used the cone shaped Dremel attachment, if I remember correctly. I made a thread on my issue with the mortising chisels. I haven’t touched the mortiser since completing the bench.

-- Bill, Yo!......in Brooklyn :)

View pintodeluxe's profile

pintodeluxe

5322 posts in 2530 days


#6 posted 08-13-2017 05:36 PM

A couple things contribute to the problem you’re having. Runout of the machine can be a culprit. Sometimes the drill bit is not perfectly straight which makes the tip of the bit travel in a larger circle than normal (bit squealing is a telltale sign).

I have a Delta bench top unit, as well as a Jet floor model. The Jet makes much cleaner holes with the same chisels. The mid priced chisels like the Jet brand are pretty good. I have been able to get good results with the bargain chisels too, but you need to grind down the diameter of the drill bit. Chuck just the drill bit into the machine, and hold a sharpening stone against the bit. Go slowly and test the bit often.

Which model Rikon did you get? The one with an X-Y table typically gets very poor reviews. I was planning on buying that model because I really wanted an X-Y table. The same tool has been sold under different brand names, and FWW magazine once said it was the only mortiser tested that wouldn’t make acceptable mortises. I then compared it to a floor mortiser, and realized the Rikon has quite a few shortcomings. However I made thousands of really clean mortises with my bench top unit, so maybe there’s hope. The best woodworkers have a way of getting excellent results with average tools.

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

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