Hi there all you happy woodworkers in USA.
Tell me, do woodworkers on this list generally have their square chisel morticers sharpened by the manufacturer or attempt to do this for themselves?
Any advice, suggestions very welcome.
Fred Page, Kington, UK.
Replies
I assume you are talking about hollow chisel mortice chisels?
When I owned a bench mortice machine I would sharpened my own chisels. The bits are sharpened just like any auger and the chisels are sharpened like a chisel, always getting the flats first then the bevel (in this case a curved inside bevel). I use sandpaper to sharpen, making sure the outsides are very flat and mirror shiney. I then wrap the sandpaper around a dowel and remove the burr from the inside (cone). By maintaining the chisels they have never had to be reground, which can be done by the factory or there are special tools available to grind the inside of the hollow chisel, but you need one for each size chisel.
Stephen Shepherd
Dear Stephen,
Thanks for answering my query about square hollow chisel mortice sharpening.
With your comments my confidence to have a go has increased.
Fred at Kington in Herefordshire UK.
Beyond the sharpening consider having a bar of soap next to the morticer. In the first plunge it is often hard to extract the chisel. (even after honing the exterior of the bit) I've found the light pressing of the bit into a bar of soap lubes up the works and makes it easier.
Anyone want to comment on the evils of soap on the joint? I figure it is a minimal contamination and the glue would easily associate with it. Provided of course it is a water based glue. I've never had a failure.
The real reason the chisel hangs up is that it binds when the hold down flexes and lets the workpiece rock. To test just grab a K-body or two and clamp the work piece and try it. Even the 1st plunge will come out easy. You just need a better hold down, not soap that may compromise the joint.John O'Connell - JKO Handcrafted Woodworking
Life is tough. It's tougher if you're stupid - John Wayne
since soap is a surfactant you do pose the risk of glue not adhereing properly. It may be of little concern in many joins, but id not risk it with joints that deal with stress and movement such as chairs.
I generally have to clean up the mortice with chisels anyway. the quantity of bar soap left has to be minimal. True it could be an issue with chairs and I will consider that when the time comes.
As for the hold down that is true. My method is cruddy at best. I just get tired of reclamping every mortice plunge. Probably worth rethinking my setup on the drill press.
I used to clean up my mortises too, but once you touch'em you're committed to a lot of fitting and you forfeit any repeatabilty in your tenon machining. No problem for a few joints, but it'll flat kill your profit in a production run of 10-14 Stickley chairs. I don't touch the mortises anymore. I punch them deep enough so I don't even need to clean-up the bottoms. That way I can machine 100's of tenons on the TS very close to a 'barely by hand fit'. John O'Connell - JKO Handcrafted Woodworking
Life is tough. It's tougher if you're stupid - John Wayne
Hi, John! So, the rough sides left by the mortising chisel don't matter if you just leave them? I assume the glue compensates for this and a firm tenon-to-mortise dry fit isn't necessary? It would sure speed things up if I understand you correctly.
Everything else being equal a smooth walled mortise with a few thousandths clearance is going to have a better glue line than a rough one which will yield a stronger M&T joint. On the other hand a M&T is a mechanical joint and if the shoulder bearing area is sufficiently large and precise the glue just holds the joint together. Most A&C chairs are fairly bulky which allows relatively big M&T joints. So it's really a question of how strong is strong enough? I prefinish my chair parts and use a moderate amount of glue so I get a little squeze-out. Just to be on the safeside I peg my joints.John O'Connell - JKO Handcrafted Woodworking
Life is tough. It's tougher if you're stupid - John Wayne
I hope this isn't too far off the topic.
When I started woodworking at the local highschool shop, we had a dedicated chisel mortiser that was fantastic, especially as the instructor kept the chisels sharp. When I began to acquire my own tools, the first was a second-hand Shopsmith, which I still use as a drill press and for disk sanding. I tried to buy the Shopsmith chisel mortising attachment, but was told they no longer make it because most woodworkers didn't keep the chisels sharp and they ended up having accidents using dull tools. Seems Shopsmith didnt't want the liability!
I would love to buy a benchtop mortiser and would do so, except that I do a lot of through-mortises, and every through-mortice I've seen done by one of these machines has a series of tiny scallops along the edges made by the drill bit inside the chisel. Is there any of these machines that doesn't do this, or is there a technique to solve the problem, e.g., use a smaller than recommended bit in the chisel?
Many thanks for any answer you may have!
By the way, the book that comes with the Shopsmith has a very detailed and useful set of instructions for sharpening mortiser chisels.
Edited 12/16/2002 8:14:33 PM ET by CHEAKAMUS
Shopsmith has them on the web site!!
http://www.shopsmith.com/catalog/html/rm_mortiseind.html
My problem w/ using the Shopsmith for mortising was flexing of the table assembly. Using a 3/4" plywood brace helps some but doesn't remove all the flex.
Edited 12/17/2002 2:08:37 AM ET by JANATION
Thanks, Janation.
It's probably 6-8 years since I called Shopsmith and was told they didn't make them any more (I think the company had just been sold). Now there's a blurb on the web site saying it's back "by popular request." I've never actually looked for or at their website before, and it's quite a revelation--they've now got just about every tool or attachment known.
You're right about table flex. I hadn't thought of it in connection with mortising, but whenever I drill a large diameter hole in a piece of really hard wood, I notice the hole has a tendency to slope to one side if I'm not careful.
Anyway, given the price (around $150) of the mortising set, if I decide to buy one, it'll probably be a dedicated machine. I've kind of moved beyond my Shopsmith these days, but I'll never sell it--there's still lots of odd little things I use it for every now and again, even a second table saw if my cabinet saw is set up to cut moldings, etc.
Anyway, thanks again for turning me on to the web site!
So... What odd jobs do you do with the Shopsmith? I've got a neighbor with one that hasn't used it for years. It is almost free for the taking if I needed 300 lbs of steel in the basement.
Morticing
What else? The table on the tablesaw looks too small to be anything other than spooky.
It's actually quite good for working close up to small things, e.g., I made an arts and crafts style lamp--a thin stick frame cut and rabbeted at odd angles to hold slag glass. The Shopsmith's tilting table did a much better job on this than my cabinet saw would have. More recently, I replaced the plywood panels on a cope and stick garage door--had to cut the old panels out, rabbit one side of the frame, and make new molding to hold the new panels in. While my cabinet saw was set up with the molding cutter, I used the Shopsmith saw to cut the moldings to length.
I also use the lathe occasionally, but don't do enough lathe work to justify buying a stand-alone machine.
Also use the horizontal boring function occasionally, though I now have a biscuit joiner, which takes over most of that work.
More than anything else, I probably use the 12" disk sander most (and I keep meaning to mount a second disk on the other end of the spindle so I can have two grits going at once).
Also, it's my only drill press, though as someone else pointed out, the table flexing can be a problem.
All in all, I still use it quite a lot and it doesn't take up all that much room--you can store things both under and over it (but you do need about 6 ft of wall space to push it up against).
Agreed, through mortises are not the strong suit of the HCM but they can be done. The drill bit wandering is a function of a loose bit so a smaller bit would make matters worse. I've found the dime gap method really aggrevates scalloping so I run the bit tighter for through mortises, leaving just enough gap so it doesn't squeal. This will make the bit run hotter and tend to burn it, so I blast it with compressed air to cool it. Having a mortiser with a 1750 rpm motor really helps in this regard as well. Truth be told I'll use the HCM mostly for through mortises that don't show all that much like chair stretchers. For something like a 1 1/4" square through mortise on a chair arm I'll rough them out with a router and finish with a chisel.John O'Connell - JKO Handcrafted Woodworking
Life is tough. It's tougher if you're stupid - John Wayne
Thanks, Elcoholic.
I'll probably continue to do as you do for my through-mortises and look for a deal on a benchtop machine for the rest--it beats setting up the router every time. (I've also considered chucking a router bit in my Shopsmith [if I had the proper chuck] and routing from above, but running the thing at full speed with no guard scares the heck out of me, it's not fast enough anyway, and the table-flexing problem would undoubtedly apply here too.
try http://www.leevalley.com the part 's are a pair of diamond hones one for basic grinding the other to put a micro bevel on the chisel corners thats important the part numbers are 77j81.20 i've used them with great results there 6.50 dollars... u.s. ... and i would use them in a drill press also..... bear
Edited 11/10/2002 9:59:07 AM ET by the bear
Dear bear,
I've found a UK supplier of square hollow mortice chisel sharpeners. It is Record Power of Sheffield. Guess what though - there is a difference in price compared with the Lee Valley cones that you so kindly recommended. For a 3/8 inch mortice sharpening tool the price is 22 pounds sterling. I don't know what that is in US dollars but guess there's a heck of a difference! I must point out that the Record Power is more sophisticated - it has a cylindrical guide fitted so that the sharpening cone doesn't drift. I don't think this justifies the extortionate UK price. Happy woodworking.
Fred in UK.
hey fred- hell i for got about this post, until a scroll back. these are probably4 pounds and i used it today and with a drill press and a waterstonethey we're good as new i love these things ....... best to all across thew pond....... cheers..... bear
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