Ptwfe - Chapter 8 - Mortising
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wear and tear
I have wondered about that as well. Especially when I was having so much trouble. I think you might be right on larger stock, and very large projects. In those cases, I can see the stresses being to much. Still, with the very small pieces that I did in the chairs, they were clearly the best option for me. Back to the original thought, if the tool is set up well, it reduces the stress greatly, if not I would agree that you risk the quill.
Saw dust heals many wounds. RLTW
Dave
Dave
Hi,
Long before they had dedicated machines "home machines" for this purpose it was though of as a drill press attachment. Along comes Norm and everyone needs a dedicated one????
If the chisel is sharp, if the bits are sharp and adjusted correctly, and you have the table braced AND you don't try to force things it works fine. If you are in a rush and want to run an assembly line of parts through the machine then do as Norm says.
The biggest issue I had was thinking the chisels would be sharp enough coming from shopsmith... no instructions saying sharpen these first... on book tell you to sharpen first... no forum to ask... However since I had knowledge from shop class I knew something was wrong.
On my set the smaller chisels have a different angle and as such a different grinding wheel then the larger chisel. I believe the current design is all the same angle. Job one is to sharpen them and remove the burrs. Once you have that done life gets a lot better.
The other thing that wasn't mentioned was the need for a table support... as you get deeper in you feel the binding... once the table is stable the binding goes away.
The length of the handle on the drill press limits the amount of pressure you can apply. I have thought about making a longer lever just for this operation to reduce the effort but not to create more force... maybe it would need to operate like a torque wrench so you don't force things to much????
By the way if you thing this operation is putting stress it is not the only one. Drilling holes in metal takes a good deal of force... as do larger Forstner bits. I certainly wouldn't worry about the quill bearings as even the cheap bearings have load ratings in the 7000 pound range each... I have no idea where the weak link will be but I'm guessing it will take a very powerful arm to damage anything. If you wish take a bathroom scale and put it on the table and a faceplate on the quill and see what kind of force you can apply.
The biggest thing is it should not be THAT much effort to do the operations. If it is then something is wrong. And keep in mind you are doing this in steps unlike you see Norm do on his machine... think two different machines...
Here is another thing you can do and I have written about this here or perhaps another site. Take a brad pt bit, say 3/8" and drill a hole 1" deep in a piece of stock. Now take the mortising attachment and just mount the chisel... the matching 3/8" one. Line the chisel up with the hole and cut out the corners of the hole with the chisel. This will give you some idea of what portion of the force is due to the chisel. If you cut in the pattern of one end then the other then the spaces between you will know the first two holes take more force due to having to chisel on four sides... the rest will be only on two sides...
All I can say is if you have one and want to use it get out in the shop and try it out. Just remember the need to sharpen and adjust the drill position relative the chisel... use Nicks dime trick if that helps.
Ed
Long before they had dedicated machines "home machines" for this purpose it was though of as a drill press attachment. Along comes Norm and everyone needs a dedicated one????
If the chisel is sharp, if the bits are sharp and adjusted correctly, and you have the table braced AND you don't try to force things it works fine. If you are in a rush and want to run an assembly line of parts through the machine then do as Norm says.
The biggest issue I had was thinking the chisels would be sharp enough coming from shopsmith... no instructions saying sharpen these first... on book tell you to sharpen first... no forum to ask... However since I had knowledge from shop class I knew something was wrong.
On my set the smaller chisels have a different angle and as such a different grinding wheel then the larger chisel. I believe the current design is all the same angle. Job one is to sharpen them and remove the burrs. Once you have that done life gets a lot better.
The other thing that wasn't mentioned was the need for a table support... as you get deeper in you feel the binding... once the table is stable the binding goes away.
The length of the handle on the drill press limits the amount of pressure you can apply. I have thought about making a longer lever just for this operation to reduce the effort but not to create more force... maybe it would need to operate like a torque wrench so you don't force things to much????
By the way if you thing this operation is putting stress it is not the only one. Drilling holes in metal takes a good deal of force... as do larger Forstner bits. I certainly wouldn't worry about the quill bearings as even the cheap bearings have load ratings in the 7000 pound range each... I have no idea where the weak link will be but I'm guessing it will take a very powerful arm to damage anything. If you wish take a bathroom scale and put it on the table and a faceplate on the quill and see what kind of force you can apply.
The biggest thing is it should not be THAT much effort to do the operations. If it is then something is wrong. And keep in mind you are doing this in steps unlike you see Norm do on his machine... think two different machines...
Here is another thing you can do and I have written about this here or perhaps another site. Take a brad pt bit, say 3/8" and drill a hole 1" deep in a piece of stock. Now take the mortising attachment and just mount the chisel... the matching 3/8" one. Line the chisel up with the hole and cut out the corners of the hole with the chisel. This will give you some idea of what portion of the force is due to the chisel. If you cut in the pattern of one end then the other then the spaces between you will know the first two holes take more force due to having to chisel on four sides... the rest will be only on two sides...
All I can say is if you have one and want to use it get out in the shop and try it out. Just remember the need to sharpen and adjust the drill position relative the chisel... use Nicks dime trick if that helps.
Ed
Ed in Tampa wrote: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.
{Knight of the Shopsmith} [Hero's don't wear capes, they wear dog tags]
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perryobear
- Gold Member
- Posts: 155
- Joined: Sun Jul 23, 2006 6:29 pm
- Location: Youngsville, NC
Hi Guys,
In addition to being a woodworking beginner, studying mortiser for me was also more of a “theoretical” exercise as I don't currently own the attachment. But I did learn some things from the chapter and that's my goal.
Adjusting the Drill and Chisel Clearance
I looked at Fig 8-3 in my PTWFE book and could not see what they were trying to show as it related to the relative positions of the drill bit and the chisel. So as dlbristol. suggested earlier in the thread, I went to Nick's Mortising Sawdust Session and it became clear. I would add that Nick also did a 3 minute Shop Tip on setting this clearance using his “One Thin Dime” method where I think the video is even clearer and easier to see.
Also of note was Nick's suggestion that in addition to feeling how the bit is cutting, that you watch the tool as it cuts to see how well the wood chips are exiting the slots in the chisel and readjust the clearance if needed.
Other Operational Tips
I'm sure Nick started with a clean, sharp tool, but he still added wax directly to the chisel/bit assembly just before he used it – no buffing, just a light smear of wax all around.
Watching Nick make the actual mortise cuts in the Sawdust Session, I noted the short, repetitive operations that take place when cutting the mortise. I think that I would need to be very careful not to let my left hand get ahead of my brain and my right hand by starting to move the wood stock before I have allowed the chisel/drill assembly to totally completely clear the the top of the stock (looks like a quick way to bend a mortising bit) – maybe I will want to remove my right hand from the quill handle first as part of my operating routine.
Still Not Sure
I'm still pondering the cautions about cutting mortises that are wider than the chisel. I understand the problem of leaving a thin section to be removed along the length of the mortise, but I'm not sure if I understand how to avoid this while always using at least ¾ of the chisel's width (we only have three chisel sizes to work with after all). I'll work it out when and if the need arises.
I'm also not sure that I wouldn't just head to the OPR (or router table) to cut my first mortise, but it was an interesting chapter none the less.
Best regards to all,
Dennis
In addition to being a woodworking beginner, studying mortiser for me was also more of a “theoretical” exercise as I don't currently own the attachment. But I did learn some things from the chapter and that's my goal.
Adjusting the Drill and Chisel Clearance
I looked at Fig 8-3 in my PTWFE book and could not see what they were trying to show as it related to the relative positions of the drill bit and the chisel. So as dlbristol. suggested earlier in the thread, I went to Nick's Mortising Sawdust Session and it became clear. I would add that Nick also did a 3 minute Shop Tip on setting this clearance using his “One Thin Dime” method where I think the video is even clearer and easier to see.
Also of note was Nick's suggestion that in addition to feeling how the bit is cutting, that you watch the tool as it cuts to see how well the wood chips are exiting the slots in the chisel and readjust the clearance if needed.
Other Operational Tips
I'm sure Nick started with a clean, sharp tool, but he still added wax directly to the chisel/bit assembly just before he used it – no buffing, just a light smear of wax all around.
Watching Nick make the actual mortise cuts in the Sawdust Session, I noted the short, repetitive operations that take place when cutting the mortise. I think that I would need to be very careful not to let my left hand get ahead of my brain and my right hand by starting to move the wood stock before I have allowed the chisel/drill assembly to totally completely clear the the top of the stock (looks like a quick way to bend a mortising bit) – maybe I will want to remove my right hand from the quill handle first as part of my operating routine.
Still Not Sure
I'm still pondering the cautions about cutting mortises that are wider than the chisel. I understand the problem of leaving a thin section to be removed along the length of the mortise, but I'm not sure if I understand how to avoid this while always using at least ¾ of the chisel's width (we only have three chisel sizes to work with after all). I'll work it out when and if the need arises.
I'm also not sure that I wouldn't just head to the OPR (or router table) to cut my first mortise, but it was an interesting chapter none the less.
Best regards to all,
Dennis