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Forum topic by builtinbkyn posted 01-28-2016 09:49 PM 738 views 0 times favorited 23 replies Add to Favorites Watch
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builtinbkyn

651 posts in 406 days


01-28-2016 09:49 PM

Before starting the mortises on my bench legs, I thought it best to do some test mortises on the cuttings from the legs. Now I’ve used a lot of machines, but never a mortising machine. I looked at a few videos and set the bit up as suggested, using a coin (quarter) as a spacer for the chisel and then running it home after the bit was fully inserted. Seems this is necessary to allow the chipped wood to clear the bit/chisel.

I first tried the 3/4” bit as the mortises will be 2”x2”. That is the largest I have. However that was used by the prior owner of the mortiser and had signs of burning. So I cleaned the bit with a wire brush and took some of the burrs off with a Dremel. Seems to be sharp, but it burns the wood and doesn’t want to plunge cut the wood very easily. Only after a gorilla force on the lever, did it make a mortise hole. That really didn’t seem like it should be necessary. It’s soft wood – cedar. I then tried a new 1/2” bit and got the same results.

They’re Shop Fox bits. Is it the bits or is it something else? Any help is appreciated.

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


23 replies so far

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bearkatwood

1206 posts in 477 days


#1 posted 01-28-2016 10:10 PM

I like to use a smaller bit than necessary for my mortises, say a 3/8”bit for a 1/2” mortise and get very close to my line and pair it true after the fact. I hone the bit and chisel and coat them with wax before each use. Also I never get as fat on the setup as a quarter. For a 3/8” bit I use a .02 card scraper for the setup up to two scrapers worth for a 3/4” bit if I go that big, which is just a pain and I would rather stick with the smaller bits. My bits aren’t anything special, and they work well when I coat them with wax prior to use. I am by no means an expert in mortisers, but this is how I have had the best luck, so I hope it helped. One other thing, if the wood is in any way wet it can bind up when you drill in, so make sure it is seasoned well.

-- Brian Noel

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ShaneA

6474 posts in 2064 days


#2 posted 01-28-2016 10:13 PM

I like to use the smaller bits too. You may try dressing the edge of the chisels too. I know there are some conical diamond sharpeners specifically for those type bits. 3/4” is just a big bite, probably a lot of force there…even with sharp bits.

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Bill White

4456 posts in 3426 days


#3 posted 01-28-2016 10:13 PM

The chisel MUST be sharp as well.
Bill

-- bill@magraphics.us

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builtinbkyn

651 posts in 406 days


#4 posted 01-28-2016 10:22 PM

So the quarter is too thick? Some of the setup examples used a dime and others a quarter or a nickel. Thought more space to clear the wood might be better but I’ll try a dime and see how that goes.

The 3/4” is smaller than the 2” mortise, but even the 1/2”, which is new, isn’t cutting it. I checked over the machine and everything seems to be fine. The spindle appears to be running true.

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

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builtinbkyn

651 posts in 406 days


#5 posted 01-28-2016 10:36 PM

Well the dime is better and a little wax seemed to help Brian, but it still seems to require a lot of force on the lever.

I’ve mortised plenty of doors for locks. I’ve only made a few mortises for furniture and that was into walnut. Hogged out the majority of the stock on a press with a Forstner bit and then cleaned it up with a chisel. Thought this would be easier using a machine. Maybe I’ll go the other route. I’ll still have to use the mortiser as I don’t have a drill press yet.

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

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AandCstyle

2575 posts in 1723 days


#6 posted 01-28-2016 10:48 PM

Bill, make a jig and use your plunge router, then clean up the corners & edges with the chisel. I have a Jet mortiser that I never use.

-- Art

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builtinbkyn

651 posts in 406 days


#7 posted 01-28-2016 11:08 PM

Yeah Art I’ve read a lot about mortisers collecting dust. Kind of like those exercise bikes that become clothes hangers LOL Glad I didn’t pay a lot for this, but I would like to use it.

I only have a 1/4” upcut bit to use if I go the router route. Maybe toolsforworkingwood has a larger 1/2” shank bit. They would be the only place around here that would have any kind of specialty bits. I’ll have to make a template and use a bushing, but the mortises are deep. Maybe hogging them out and cleaning them up with a chisel is the best route.

Not giving up on the mortiser just yet. They have these hollow chisel bits. Look to be much better machined than the Shop Fox bits, but expensive though.


Bill, make a jig and use your plunge router, then clean up the corners & edges with the chisel. I have a Jet mortiser that I never use.

- AandCstyle


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

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conifur

955 posts in 617 days


#8 posted 01-28-2016 11:23 PM

I have a Delta and have use a Craftsman that I think were made by the same company. I have mortised, oak, walnut, cherry and ash, without a gorilla force needed, wax the exterior chisel sides, bit down about a dime, I never hogged out with a prior machine/operation. Not that is not a bad idea for a large mortise, if a deep mortise I would not use a Forstner bit but a would twist/brad point, or a router.

-- Knowledge and experience equals Wisdom, Michael Frankowski

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builtinbkyn

651 posts in 406 days


#9 posted 01-29-2016 12:40 AM

Didn’t mean I would hog out the holes before using the mortiser. That would kind of negate the need to use the mortiser. I would hog them out and then clean them up with a chisel and I would use a Forstner bit if I had a drill press. If I do use the hog/chisel method, I’ll use the mortise bit without the hollow chisel and then clean them up with a hand chisel. I still want to use the mortiser though :) I think it’s the cheap Chinese bits that suck. Looking at their machining, it’s rough and not refined. I could see how cleanly machined bits would certainly do much better. The machining on the bits I posted above in the link look nothing like the Shop Fox bits what so ever.


I have a Delta and have use a Craftsman that I think were made by the same company. I have mortised, oak, walnut, cherry and ash, without a gorilla force needed, wax the exterior chisel sides, bit down about a dime, I never hogged out with a prior machine/operation. Not that is not a bad idea for a large mortise, if a deep mortise I would not use a Forstner bit but a would twist/brad point, or a router.

- conifur


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

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JBrow

819 posts in 386 days


#10 posted 01-29-2016 02:32 AM

builtinbkyn,

The hollow chisels in the link in one of your prior posts on this thread look pretty nice. I purchased Powermatic Chisels. The ones you are looking at are priced about the same. Good chisels will make a difference.

However, I am not sure the chisels you have is your problem. After all, you continued having the problem with a new chisel and bit in cedar. Therefore, I suspect there is something not quite right in your setup.

My suspicion is that as you advance the chisel and bit, the auger bit is not creating a hole in advance of the hollow chisel or the hole is too small. Even in soft wood like cedar, you would have to practically stand on the lever arm to advance the chisel and bit if the auger is not cutting a proper sized hole ahead of the chisel.

I doubt the quarter spacer is the source of your problem – assuming the auger bit was chucked in final position with the cutting edge of auger bit’s lifter flush with the four points of the hollow chisel while the chisel was against quarter spacer. Removing the quarter and fully seating the chisel would mean the auger advances ahead of the chisel a little more than if you used a dime spacer. The quarter space results in a mortise bottom that requires a little more hand chisel work to cleanup, if you are so inclined.

Once the auger and chisel are in their final position, it is a good idea to inspect the cutting edges of the bit and chisel. The auger bit should project below the corner points of the chisel. Also the auger should spin freely inside the chisel without a lot of metal on metal noise. If the auger is not set properly, it will require an incredible amount of force to drill your hole (don’t ask how I know). Also, the bluing you mentioned on the ¾” set suggests that the prior owner did not always set the chisel and bit correctly.

I assume the augers you are using with the chisels are properly sized to just fit inside the chisel. The auger should be the largest auger that can fit inside the chisel and still rotate freely. If the auger is too small, there will be a lot more material for the chisel to pair away.

To determine whether your auger is sharp, you could use it by itself (no hollow chisel) to drill a hole. If the hole is drilled without a lot of force, it is probably sharp enough and not the source of your problem. If dull, as with any dull drill bit, it requires a lot of force to drill a hole.

A sharp chisel is helpful, but probably not as important as the things mentioned above. A dull chisel will crush the wood as it advances, probably leaving a sloppy looking mortise. But I doubt it would add a lot to the force required to drive the chisel and bit. However, the chisel should be sharp and it will make a difference. A sharpening cone that dresses metal inside the chisel is the best method for sharpening the chisel. There is less of a chance to alter the dimensions of the chisel and hence the mortise dimension. Since you had the same problem with a new ½” chisel, I am not sure that a dull chisel is the problem.

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builtinbkyn

651 posts in 406 days


#11 posted 01-29-2016 03:10 AM

Hi JB and thanks for the reply. The auger used with each of the bits were the proper size. The 1/2” bit was still wrapped in plastic sheet inside the boxed set. The auger bits cut just fine when not housed inside the chisel. However there is a metal on metal sound when turning and that is after using the spacer method. I’m just wondering if these bits had some manufacturing issues. That does happen from time to time in the world of woodworking tools – or so I hear ;)

The 3/4” may very well be too dull – both the auger and the hollow chisel. It was not new and was blued and had pitch on it. I cleaned it as best I could. Though I don’t have a large enough conical grinding bit, I’ll try to give it a sharpening with the Dremel. I understand the idea that the outer side of the chisel isn’t what needs sharpening. It’s the inside cove that has the edge. At this point I have nothing to lose with that bit, though I’m pretty sure I can put an edge on it.

After looking at the “set” in this article, I see much more of the auger exposed than what I had exposed. Using even a quarter, there wasn’t as much of the auger exposed as I see there. The article also explains that softer woods require more offset than hardwoods as they create larger chips. That makes sense to me. I guess I’ll play around with it a “bit” tomorrow and move on to other means if it doesn’t work.

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

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CL810

3452 posts in 2454 days


#12 posted 01-29-2016 04:03 AM

Bill, if you have FWW subscription this video is worth watching.

-- "The only limits to our realization of tomorrow will be our doubts of today." - FDR

View JBrow's profile

JBrow

819 posts in 386 days


#13 posted 01-29-2016 04:06 AM

builtinbkyn,

I was unaware that softwood and hardwood required a different set up. I will keep that in mind – thanks.

Since you are hearing metal on metal, I have to believe this is the source of your problem. In effect, you may be trying to drill a square hole (a lot of force), rather than a round hole that is then squared up by the pairing action of the chisel (moderate force).

Perhaps, rather fiddling with the spacer, since with your chisel and bit it does not seem to be working properly after using the quarter spacer, try setting the chisel in final position. Then drop the auger a little at a time and check for the metal on metal noise. When the metal on metal noise seems to have mostly disappeared, try cutting a mortise.

By the way, I have a ¼” chisel set in my mortiser. I just now turned it on and there was zero metal on metal noise. I included pics of this this set-up.

Also, to troubleshoot your problem, I recommend using the new ½” chisel set. This will eliminate any doubts that may exist with the ¾” set. Once you figure out the solution to the problem, you could install the ¾” and if it works, cut your mortises with the ¾” set.

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builtinbkyn

651 posts in 406 days


#14 posted 01-29-2016 04:36 AM

Thanks both, for the replies. FDR that video was helpful and will use that as a guide to sharpen the sets. Even the new set has a roughness on the inside of the chisel that doesn’t look right. Could be causing the chips to bind.

JB your setup has much more auger exposed than what I had using the coin. I’m going to try what you suggest and set up with more of the auger exposed beyond the chisel. When I mounted the bit, I pushed it up into the spindle until it stopped. After tightening it I pushed the chisel up until it seated against the boss. Maybe the auger went too far in. However all of the info I found on the setup was to insert the auger “all the way up”. Clearly, based on your pic and the pic in the link I posted, has much more of the auger exposed than what I had and could be the issue for the grinding and the poor performance.

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

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builtinbkyn

651 posts in 406 days


#15 posted 01-29-2016 07:09 PM

Well I think I have found the problem. A cheap Chinese facsimile of a hollow mortising chisel. The one below is “new” meaning it was still in the plastic shrink wrap inside a four set Shop Fox box pictured below as well. The closeup of the 1/2” chisel was in the same plastic wrap before I used it. As you can see, the machining is horrendous. The bit was used to attempt to make two mortise holes before I took the pic, and that was into soft wood, so it wasn’t the use that created that horrible profile.

Because of the horrible “rifling” of the flute of the chisel, wood chips are not clearing and the bit cannot plunge thru the wood effectively. Wish I could take better pics, but that’s the best I can get with an iPhone. I should be glad these were thrown in as part of the CL deal. The prior owner was probably having the same difficulty I am and chose to abandon ship on the mortiser. I’ll have to make a trip to toolsforworkingwood to pick up some real hollow mortise chisels. I’m not going to waste time trying to fix these.

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

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