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JCD
01-29-2010, 11:57 AM
I'm both a metal worker and a woodworker and have the luxury of sharing my tools between both hobbies.
I have a mortising jig that I use from time to time on my drill press, and it does a nice job. But, I miss the luxury of the accurate x-y axis movement my Bridgeport mill offers, so I am giving serious consideration to making a mortising jig for my Bridgeport.
Does anyone out there have a design for such a devise? I could design one, but I think someone has already done that and it probably works very nicely.
If you do, will you share your good fortune with us?

John Stevenson
01-29-2010, 12:05 PM
I don't think a Bridgeport will be accurate enough for mortising wood.

.

Toolguy
01-29-2010, 12:10 PM
Maybe not, but hopefully someone can help this poor unfortunate guy scrape by with what's at hand.:p

Ian B
01-29-2010, 12:45 PM
Hi,

Yes, I made such a beast a few years back, for my Beaver turret mill. If my camera defrosts, i'll take some pics tomorrow.

Basically a pear-shaped lump of 20mm thick plate that clamps around the quill, a round rod that drops down past the chuck, and then an arm back in to hold the mortising cutter under the chuck. It puts a 1" square hole straight through hardwood, no probs.

While I was at it, I also made an adaptor to hold a small wood router.

Ian

Forrest Addy
01-29-2010, 12:48 PM
Huh!! A Bridgeport is a morticng jeweel both in rotary as with an endmill ground for wood and with regular chisels mounted on shanks as spindle tooling used reciprocaally. If you have a slotter head so much the better.

I've done a lot of precision mortices on a BP. It might be a little slower then on a morticing machne or a drill press but very do-able. If you make a spindle adaptor to accept rotary morticing chisels the distinction disappears.

And you are right: the finely controlled X-Y motion on a BP is a real advantage ofer a plain old morticer.

JCD
01-29-2010, 01:56 PM
Thanks Ian, I'll Wait for the thaw.

Ian B
01-30-2010, 04:52 AM
JCD,

I quickly rigged the mortise attachment up - have a look at:

http://smg.photobucket.com/albums/1003/IanBartlett/Beaver%20Mortising%20Attachment/

It's just bits of plate & bar, allowing the mortise chisel to be firmly held below whatever chuck you have. The key thing is "firmly" - there's quite an overhang, and if the chisel gets out of alignment with the chuck, it'll bind up fast. As you can see, it eats vertical height - I could have made it more compact by shortening the shank of the drill.

The split cotter to clamp the mortise bit into the holder is missing - I have it somewhere, but it was -4C in the workshop!

With a mill, you have lots of ways of making square holes as Forrest says - but this is really quick and effective. The chisels are cheap enough, I have a range of sizes from 5/16" to 1".

That piece laying on the table is the adaptor for a small router.

Ian

Bguns
01-30-2010, 05:28 AM
John S, must have one of those worthless English made BP's

:)

American ones are much better....

oldtiffie
01-30-2010, 06:25 AM
Why not just keep using the drill press but put a good "X"-"Y" table on the drill table?

https://www.machineryhouse.com.au/Products?stockCode=M206

https://www.machineryhouse.com.au/Compound-Tables

There are cheaper ones too that really are not too bad at all for the price.

Keep the wood chips off the mill.

John Stevenson
01-30-2010, 06:27 AM
John S, must have one of those worthless English made BP's

:)

American ones are much better....

It is actually :D

Instead of 10 thou slop we have 10 microns :D

.

oldtiffie
01-30-2010, 06:35 AM
Geez John.

That much slop would feed the pigs and chooks here for a week!!

Perhaps Farmer Giles could use the BP for mixing the slops.

Ian B
01-30-2010, 07:35 AM
Tiffie,

Why not use a drill press and an X-Y table? From the link you gave, a table is $500, and weighs almost 60Kg. Expensive if you already have a mill with an X-Y table, and also a hell of a lump to lift on & off.

Is having sawdust on a mill a problem? When I clean sawdust off mine, it seems to take all the old gunk & fine swarf with it; I even keep sawdust in a bucket beside the lathe for cleaning the drip tray out.

Ian

Doozer
01-30-2010, 08:36 AM
I don't think sawdust on machine tools is much of a problem if you use a shop vac to clean it up. If you use an air hose, then it gets into unwanted placed.

--Doozer

JCD
01-30-2010, 09:29 AM
Ian,
Thank you for sharing your design, I think I'll make one.

gwilson
01-30-2010, 11:38 AM
It seems to me that the Beaver design would not be very strong,and would bend if much pressure were put on the mortising chisel. If I were to make an attachment,I'd turn a round attachment that would fit around the spindle,have an opening in its middle to get at the chuck and tighten it,and hold the diameter of the mortising chisel at the bottom. That way,all stress would be right up the centerline of the spindle and mortising chisel. You'd need about a 4 1/2" or larger bar of metal to make it from.

To me it's moot anyway,because I'd NEVER risk breaking off the teeth on the spindle housing,or on the spindle handle from putting a lot of pressure on a mortising chisel with a machine not designed for that use.

I just mill a slot,and quickly square off the corners with as wood chisel by hand.

When I was the toolmaker for Colonial Williamsburg,I worked out a way to make the escapements for wooden planes with sharp D2 chisels using the slotting attachment. First,though,we drilled out as much wood as possible,and routed the mouth of the planes up from underneath the plane's soles. It worked pretty well. We got where we could finish up a drilled plane escapement in about 15 minutes. And,it had true chisel marks,not router marks in it when finished.

We made a 1/4" thick D2 saw with VERY coarse teeth to saw the places on each side where the wedge of the plane would go. It went right through the planes,and right out the bottom,squaring up the throats of the planes. The initial router marks were cut away by the reciprocating and powerful chisel cuts.

Ian B
01-31-2010, 03:29 AM
Gwilson,

I've now used this setup several times on hardwood. I take your point on the round attachment - that's what most of the commercial ones that fit the Chinese drill presses look like. They tend to be made of cast alloy.

So far, I've seen no signs of anything flexing.

Breaking teeth off the quill etc? Well, from using it, the force required is about the same as for putting a 10mm drill through steel - hardly enough to bother the machine. The drill down the centre of the mortising chisel removes about 80% of the wood, the square outer housing shaves of the rest.

Works for me...

Ian

oldtiffie
01-31-2010, 03:46 AM
Tiffie,

Why not use a drill press and an X-Y table? From the link you gave, a table is $500, and weighs almost 60Kg. Expensive if you already have a mill with an X-Y table, and also a hell of a lump to lift on & off.

Is having sawdust on a mill a problem? When I clean sawdust off mine, it seems to take all the old gunk & fine swarf with it; I even keep sawdust in a bucket beside the lathe for cleaning the drip tray out.

Ian

Yes, I was a bit "over the top" there Ian - thanks.

Here is the entire "milling" range:
https://www.machineryhouse.com.au/Compound-Tables

But to go "down-market" a little, there are some very cheap ones that have a vise built in. They are surprisingly good for the price.

Ian B
01-31-2010, 04:49 AM
JCD,

The other nice thing about using mortising chisels in a turret mill is that you're not limited to 90 degrees - the head can be swivelled or nodded to pretty much any angle you please. There's enough advise elsewhere on this board about how to get the head square afterwards!

On the subject of using metalworking equipment for woodworking; do you happen to have a horizontal mill? I've often thought that a chain mortiser could be modified to be clamped to the overarm and driven by the horizontal spindle.

More tools to make.

Ian