Ptwfe - Chapter 8 - Mortising

[charlese]

Holy Cow! I'm really not ready to jump to another chapter yet, but it's time! If we don't proceed weekly, we won't be able to get through this book in the scheduled six and a half months. If others are like me, they are not yet through with Jointing and Drilling chapters. And I believe that's what was anticipated at the beginning. We CAN go back and dig up any one of these chapters at any time, and as you know - one added posting can bring on a flurry of more - replies, questions, answers and comments. (Isn't it fun?)

This chapter is very short and is limited to drilling mortises using the Shopsmith Hollow Chisel Mortising Attachment. http://www.shopsmith.com/academy/mortis ... ex.htm#top

This is a bit strange to me, as Shopsmith stopped selling this tool for a number of years. Then it was brought back around 1960. They had discontinued it (as I remember) because of the popularity of rounded end mortises. Also, if I remember correctly, it was brought back by popular request.

We will be depending on those of us using the Hollow Mortise Attachment to hold their own on this Thread.

As we know, there are many other methods to make mortises, I think (just my thought) we should limit this site to the subjects in the chapter.

EDIT: FIXED THE LINK

[reible]

Hi, Looks like your link doubled up or something Chuck. Anyway here is another try and it should work. http://www.shopsmith.com/academy/mortistenon/index.htm Going to go do my reading now. Ed

[a1gutterman]

Well, I read it. I do knot have the attachment, so I do knot know if I will ever try this.

[reible]

The good news is this chapter is a short read. I've been having trouble keeping up on our reading project and have several things from last weeks I haven't had time to post... I'll get back to that sometime soon

I hope. This method of mortising just like the old shopsmith were prominent in ads in the back of the handcraft magazines and were always of interest to me. I knew one day I'd like to own them and both of those wishes have come true.

This was not something we had in our home shop nor did anyone else I knew. It wasn't until shop class in high school that I really got to see one in action. It was an attachment to the drill press much like this one that shopsmith sells.

I struggled with mine when I first got it. I assumed I could just take it out of the box and use it. It turned out the chisel part wasn't very sharp and that makes a LOT of difference when trying to chisel the square portion of the hole. Once I had that figured out came the second problem... I traced that to the table tipping from the force of the operation. I don't recall shopsmith having a table support at the time so I had to become creative.

I cut a small notch in a 2x4 that the front of the table fit it, maybe a deep or so. I would then raise the table and lower it over the 2x4 then lock the table in place. As long as you didn't kick the 2x4 it worked fine and once the table is stiff the operation is improved. Now you can buy a support for the older tables(555627), the newer 510/520's come with the parts you need.

It was some year later that I found out the outsides of the chisels can be polished which also helps out... just don't get carried away and take off to much material so they become undersized. Another improvement was getting the 3-lever drill press handle (555491). Arm position means a lot so you might want to play with that as you work. Some people have an easier time with towards you and down while other might do better with the down and away.

Ed

[reible]

OK what happened to my paragraphs in my last post????????

Tried to edit it and fix it but it posted the same way again?????

This is a test to see if the same thing happens this time.

Ed

Edit: Yes it did! I'm running the firefox beta 3.1 beta3 so this maybe a bug. I'll restart it and test again.

Edit2: Nope couldn't fix it that way either. Must be a bug?? Anyway I'm now in a Safari beta doing the repairs. If these work then I'll know it was an editing problem or if is not fixed it is a display problem with firefox.

[robinson46176]

I have a couple of the SS mortising attachments acquired when I bought complete machines. It is my current plan to use one of them almost altogether on my old 10-ER since it is built much heavier especially in the way tubes. That and the cast iron table and table support parts should make a separate table support unnecessary. In the past I tended to avoid mortise & tenon joints except for open mortise joints and used things like doweled joints or biscuits or even half-laps instead. I look forward to using one of these attachments if I EVER get my shop half way organized.

[JPG]

Thank You! I learned something today. Should have realized it myself, but sometimes the obvious is overlooked. I am assuming the '1/4 n' referred to in the last section should be "1/4 in". OR it could be referring to depth of mortise 'n'. Either way partial depth cuts IS a good idea. In addition to minimizing breakout(between adjacent 'cuts') it gives the chisel additional opportunities to 'clean up' the mortise wall.

[dlbristol]

There is a great sawdust session that addresses most of my situation with the mortising chisel. Go to the very first session , Aug 11, 2007 and choose part 1 of the first session. My experience with the mortise chisel started badly but has improved greatly.. Any thing I can add to this discussion is really the result of my initial failures! My first suggestion is to read the heck out of all the stuff on the tool, go to Nicks sawdust sessions and you have a better chance of making the tool work well. ( Imagine that!) I assumed that the chisels were sharp enough to use when I got them. Not so. I managed to get one of the bits hot and didn't know how to sharpen it. I have had some success sharpening the chisel, using the horizontal drill press mode, the fence and the block to hold the chisel. The bit however has been a different story. I think it is done for. I know now that I had the bit set incorrectly. It was not protruding far enough from the chisel. I now use Nicks dime method and that helps.
Part of my problem came from practicing with pine and then doing the same thing on red oak. There was not any problem with the pine even though I had the set up done poorly and the chisel was not sharp. When I went to oak, the results were different.
The table has to be supported IMHO especially if you are working with hard wood. I believe that part of my early issues were the result of the table deflecting causing the chisel to bind and the bit to get hot. After supporting the table, I had less problems. The chisel retracted from the stock much easier as well. I also used a 2x4 directly under the Quill to add rigidity to the operation. The legs are fine, but they are not in line with the greatest amount of pressure.
After correcting the set up and sharpening issues, I have had success with the mortise chisel. ( As with most of my messes, set up is a big part of the problem) I had to slow down the cuts and back out often. I don't try to go the full depth on the first cut, and I try to stagger the overlaps on the second or third cuts. Suffice it to say I can't go as fast as Norm does!

When you sharpen, be sure that you have the correct stone. Apparently there are two different tapers on the chisels, depending on when they were made.
I did try to polish the sides of the chisel, but I didn't do much because of the concern about changing the size. I did clean them well between uses and that helped. I now think the tool is a good way to go if you are careful with the set up and can touch up the chisel and the bit.

I have done some "mission style" rockers patterned after a hand made one from my wife's family ( not sure how old, but at least 75 years) and putting a mortise in a narrow slat in the back was easier to do with the mortise chisel than with a brad point bit. The chisel seems to stabilize the whole operation, and cleaning up by hand on these narrow pieces appeared hard for me to do with out breaking something.

I thought about waxing the outside of the chisel to reduce friction, but never got the courage to do it. I wonder if that would help?

[markap]

I've only used the 1/4 mortise chisel on walnut so far. After the first couple cuts, I did wax the outside of the chisel and that made quite a difference. I have since acquired the sharpening stone but have not used it yet.

[Ed in Tampa]

I may be very wrong with this but I question the wisdom of doing mortises on the SS. I did a half dozen using the mortising set up and decided that the wear and tear on the SS made the practice unacceptable.

I have had this further fortified after examinining and comparing a standalone motising machine to a SS. There is some heavy duty iron parting on a alone Mortising machine and that iron is there for a reason. Just a comparison between the control arms convinces me that SS was not made for Mortising. Or compare the deep thick teeth in a mortising machines feed rack compared to the tiny shallow teeth of the SS quill rack.

While I never had a problem or caused a problem doing mortising on my SS I decided to no longer do it. To me it put too much strain on the bearings, the quill, the quill feed mechanism.

My opinion.