Ok last week I loved it now I hate it. Got me a mortiser and started really
using it this week and while getting into the real workings of the thing I
have totally changed my opinion about them. Or at least the one I have, the
Delta. First thing I noticed was the fact that when centered on 3/4" stock
(yeah I know how un-common right?) the damn head hits the post that the hold
down it mounted on preventing you to make a mortise deeper than 9/16-5/8. I
was trying to make a 3/4" deep mortise and couldn't figure out why the damn
thing wouldn't go any deeper. That's why. Second thing, when finally getting
it to go deep enough by laying a piece of 1/4" ply on top of the table thus
raising the stock, I was mortising right along, made about 10 mortises when
"snap" the 1/4 bit broke. I thought ok what the hell it was the bit that was
included with the machine and was probably not that good to start with. Went
to the 5/16 bit. Not in the center anymore. Why? Didn't move the fence.
Checked the fit of the chisel in the head and guess what, severe play! The
damn chisel moves front to back a significant amount before setting the
set-screw. Setting the screw of course locks it in but where? Back? Front?
Side to side? Its moving all over the place. I locked it, then loosened it,
and locked it again several times to see if it was repeatable with no luck.
Different everytime. I just feel this should have been a closer tolerance
than what it is. It was just enough that the rails aren't flush with the
stiles now. Anyway, I think I'm going to play with it some more but it looks
like I may break out the 10 year old shop made horizontal router table I
used in the past. At least I know all of its perks!
One possible confusing part of my post. When I said "why? Didnt move the
fence." I wasnt answering my question, I was stating in fact that I never
moved the fence so the bit should have still been centered no matter what
size it was. If it was in the middle to start with which it was.
What is the size of your stock? I made 1 1/8" deep mortises, but perhaps my
stock is wider (taller?) than yours at 2". There is a limit to the travel
of the quill and also the total depth.
Can't be much help here as I've only used the 1/4" so far. Not only that,
but it is -10F and I'm not going to the shop to try my other chisels right
now. My 1/4" is a good fit and accurate. Perhaps you should try another
size to see if the slop is due to the chisel or in the mount.
Hey good call there Edwin I didnt think of that. I will try the other bits
to see how they fit. Damn it couldbe that it was just a defect in the 5/16"
chisel. Long shot but maybe!
PS: Stock is 2" thick. Another solution would be to attach a wood fence face
and that would bring it out far enough to clear I guess. I just thought this
was a bad design since 3/4" is such a common thickness in woodworking.
I have been sitting back watching the posts of the people who loved their
new mortiser and wondering if anyone would change their mind. Like you, I
liked my Delta mortiser for about a week but quickly ran ito the
limitations. Below is part of one of my posts from last year:
"I read articles about tune-ups and positioning of the drill/chisel but was
still not happy. Next step was to purchase the better chisels and
sharpening system. I had a little better performance but still not great in
hard woods so I called Delta to see if it was a problem with my unit. They
told me to bring it to their service center."
When I went to pickup the unit I was told that they could not find anything
wrong. They even did a few test cuts for me in some fir and showed me the
correct technique. I had some maple in the car so I asked to test on maple.
The results were horrible on the maple...even with the "correct technique."
The technicians told me that my expectations were too high and not to expect
a precision machine for the price."
I upgraded to a slot mortiser and love it. It is accurate, repeatable,
simple to setup, and works on the types of wood that I use! I moved the
Delta to my vacation house about three years ago, where I have a little
shop, and have not used it since. I have cut all of my mortises at that
home with a plunge router.
Bob McBreen - Yarrow Point, WA
I have a Laguna slot mortiser. It is basically a table with X, Y, Z axis's,
and a mount to attach a router to. It is similar to the table that attaches
to the Robland combo machines. The biggest difference is on the combo
machine you use the power from one on the motors, and not a router.
To cut a mortise you set the shops, clamp the piece, and cut. I think that
there are two downsides. The first is that I keep an extra router attached
permanently. The second is that it cuts round mortises. I find both of
these easy to live with as I had an extra router and it is easy to round the
corners of tenons. It really excels at floating tenons. I batch process
the tenons in different sizes and do the round over with a bull nose bit on
the router table.
Bob McBreen - Yarrow Point, WA
One of two things ... the new Delta's ain't what they use to be (very
possible, but they'd have to be pretty bad), or you have an operator/setup
I've been cutting _accurate_ mortises with my Delta, using all sizes of
bits, for a good while and have never experienced the kind of problems you
are talking about.
"James D Kountz" wrote in message
Sounds like you have a problem with the way you put your mortiser together.
Go back to the instruction manual and see if you can figure it out from
There is NO way the head will hit the hold down post unless you have the
hold down post installed too high, or you have the dampening cylinder
installed incorrectly. Simply back off on the screw that holds the hold post
in place, adjust it properly, and see if that doesn't solve that problem.
If you put the tool together correctly, the downward movement of the head
should only be restricted by the damping cylinder.
If you need more mortise depth, or you are using particularly thin stock,
place a board on the table of sufficient thickness to give you the depth you
need. ALL mortising machines require this to some extenet.
A flawed bit and an operator problem. Get some good bits, keep them sharp,
and you won't have the problem. The centering problem is an operator
problem. When you change bits or blades on just about any piece of
woodworking machinery, your workpieces postion, with regard to things like
fences, almost always changes.
If the 1/4" bit/chisel didn't exhibit the problem, none of the other
bit/chisels should have exhibited the problem. Once again, sounds like a
From your description, it doesn't sound as if there is anything wrong with
the mortiser except some minore setup tweaks, the need for a bit more
operator familiarity, and more than usual bad luck with the Chinese bits
shipped with the machine. With regard to the bits, all mortiser's, including
the Powermatic, will work much better with quality bits. Buy some and keep
Good luck ... and don't give up on the tool, it will do the job if setup and
I never said it didnt cut accurate, its just that if you have the point of a
bit centered on a piece of 3/4" stock and the stock never moves nor the
fence. You then chuck a larger or smaller bit in, and again the stock and
fence are the same, the POINT of the new bit should still be centered unless
something else has changed. In this case its the fit of the chisel in the
head. It got alot of play in it and I feel it shouldnt have. Upon further
inspection I discovered that the bit is staying the same but the chisel is
NOT centered on the bit just exactly. It should fit better to allow for
centering to remain the same so one doesnt have to adjust the fence
Yes way. Post is down as far as it will go. Head hits the post when centered
on 3/4 material, and going to a depth of 5/8" on 2" stock. Would you like a
picture? Trust me, I went over this thing for an hour and a half and without
raising the stock (2") with a piece of 1/4" plywood or something this thing
is hitting the post. Went back over the manual, everything is correct as per
the instructions. Dampening cylinder is correct, hold down and post are all
installed accordingly. I could get it to go about 5/8" or so but thats when
I agree but this isnt happening. Again I could send pictures if you like.
Again I agree, but with 2" stock 3/4" thick come on. This is not an uncommon
size at all and should be accommodated with a machine like this.
I thought ok what the hell it was the bit that
So you're saying the center point will change? Okay lets for example use the
drill press which is the closest other tool in the shop. Ok, You have a 1"
forstner bit with the center set 1/2" from a fence, your bit is now touching
the fence and the center of the bit is exactly 1/2" away from the fence.
Okay? Now then you chuck say a 1/2" bit in the drill press. Although the bit
is now 1/4" away from the fence the POINT of that 1/2" bit is in the exact
same place as the 1" bit. Or at least it better be or you have a screwed up
drill press. If your stock was say 2" wide you would have a 1" hole and a
1/2" hole but they would BOTH be centered 1/2" away from the edge. Make
sense? This should be the same on the mortiser but because of the slop in
the hole the chisel mounts in it allows the chisel to be placed side to side
or back and forth just enough that the squared up portion of the mortise is
now out of center. Thats whats happening here.
Sounds like the post is too long? I just went back out to the shop and
measured mine. At the heads lowest extension, the head misses the top of
said post by 3/8" ... nowhere near touching ... and the bit/chisel is
exactly 1" above the table, allowing for a 1" deep mortise in 2" stock
sitting flat on the table.
Might want to consider cutting about 3/8" off of it.
If you are drilling your mortises dead center, true ... but that is unusual,
Still think you got some bum bit/chisels ... and it sounds as if the hold
down post was cut to the wrong length.
If you need any further measuring as a go by, let me know.
Something wrong here. I just cut a bunch of 1" deep mortises in 2" x 3/4"
stock. Now you are making me go out in the cold to check what you may be
talking about. I have nothing hitting any post.
I just put the head all the way down. There is just about 1" clearance under
the bit. I slid a 1" wide rule under and it just touched. The post for the
hold down extends about 4 1/2" above the base. Perhaps your post is too
long or not seated properly. It is held with a set screw from what I saw.
At 6 degrees outside, my measurements may be off a tad as I was not taking a
lot of time holding metal tools to do anything. .
Got me laughing now, sorry about makin you go out in the cold there Edwin!
Thanks to swingman and all the others that offered advice on this. I do
agree with swingman that I probably did get a bum bit, I'm looking into some
top quality bits now and will probably get them in a few days (he hopes). As
far as the head hitting the post well, dammit I just don't know! Very weird
to say the least. The only logical explanation seems again to be what
swingman said, the darn post is just too long. I guess its possible. After
simmering down today and going over the whole thing again I have decided
that none of these problems aren't something that couldn't be fixed or
worked around easy enough although I hate having to "fix" a new machine or
anything else new for that matter. I'm looking into this cross sliding vise
retrofit and think that would have to be a huge improvement. In the meantime
I'll be plunging away with it at 5/16" by 5/8" deep. So until further
Thanks again to everyone,
I can't speak to the problems with the bits, but toss your fence and install
an x-y sliding vise. My Jet sat under the work table for months until I got
around to doing this. I couldn't believe the improvement. Now I use it all
the time. I posted a pic on one of the binaries groups a few weeks back.
If you decide to do this, I'll assist in any way I can.
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