Replies

1. 
   Steve50 | Sep 07, 2005 04:24am | #1

   Yogi - I replaced my Delta mortiser earlier this year and no longer have a hollow chisel mortiser.  As I recall, my original chisels had machining marks on the outside faces that were noticably rough running a fingernail across them.  I honed and polished the outside faces of the chisels as I would a plane iron and did not experience this.  Also, make sure you have clearance between the bit and the chisel. 

1. 
   Yogi | Sep 07, 2005 04:32am | #3

   Steve-  Thanks for the heads up-  I'll check the outside faces for irregularities-  And, yes, the bit seems to contact the chisels-  What, if anything, is there to be done about that?  And finally, did you just go back to drilling and then cleaning with hand chisels, or is there a better way?  Thanks for your thoughts-

1. 
   Steve50 | Sep 08, 2005 02:02am | #10

   Yogi - I set the chisel in place with a 1/16" thick formica shim between the top of the chisel and the mortiser housing.  With this in place, I tightened the bit in place contacting the bottom of the chisel (use a block of wood to hold the bit up to save your fingers).  Once this is done, remove the shim and re-position the chisel fully in the housing.  Doing this will provide adequate clearance between the bit and the chisel.  I was able to get satisfactory performance with this setup and never went back to hand chiseling mortises.  The chisel & bit sets provided with these machines are of pretty low quality, so you may want to consider upgrading if you can't get what you have working properly.

   The upgrade I did was to a slot mortiser and floating tenons which is must faster. 

   Steve

1. 
   Yogi | Sep 08, 2005 03:08am | #11

   <<<"...I was able to get satisfactory performance with this setup and never went back to hand chiseling mortises...">>>

   Music to my ears-  I know there are many alternatives to the mortising machine, and they all have their plusses and minuses-  Seems like getting the machine set up properly to operate as it was intended (assuming this to be possible) would be the shortest rout in the long run to dependable repeatability-  Thanks for the benefit of your experience-  Dave

2. 
   Yogi | Sep 08, 2005 03:56am | #12

   My word-  I didn't even know what a slot mortiser was-  I'm still a little blurry on how it works, though I looked one up on Google-  I'd have to sell the house to buy one of those-

2. 
   WillGeorge | Sep 07, 2005 04:30am | #2

   I have a cheep old Jet (I usually just use a router)..

   I find that backin' out the bit OFTEN and cleaning out all the crap works OK!

3. 
   jako17 | Sep 07, 2005 04:35am | #4

   Take a good look at the hold down if it is allowing the wood to lift and twist even a little, it will cause jams

1. 
   Yogi | Sep 07, 2005 05:40pm | #6

   Thank you-  Will do-

1. 
   jako17 | Sep 08, 2005 06:15am | #14

   Another thing I have found useful on my multico( which was a precursor to delta before they produced their own) is the spray Teflon that is used for saw blades.A good shot of that down the bit in the hollow chisel helps make a clean cut.

1. 
   Yogi | Sep 08, 2005 08:12am | #16

   I'll try the spray teflon, too-  Thank you-

4. 
   philip | Sep 07, 2005 07:28am | #5

   Yogs,
   Jaco brought out a valid point.
   Also, check out the chisel itself- I once had one from a reputable manufacturer and it was tapered i.e smaller at the cutting end, so the deeper it went the more it wedged.
   The hold down system must not allow the slightest movement upon withdrawal-this is a failing with some lighter types and those drill press add ons.
   The auger should be the correct size for the chisel-might be obvious, but I have known people to have mixed these up and put a 6mm where a 1/4 inch should have gone.
   At no time should that auger rise up the chuck so that its shoulders rub on the chisel mouth-that is the kiss of death. the auger needs to project just enough to cut ahead of the points of the chisel.
   I think the hollow square chisel mortiser to be an under rated machine-I suspect it is because people do not take care in setting them up and maitaining them.

   Philip Marcou
1. 
   Yogi | Sep 07, 2005 05:43pm | #7

   Thanks very much-  I very much appreciate everyone's input and will proceed accordingly-  Much obliged-

5. 
   douglas2cats | Sep 07, 2005 06:54pm | #8

   Ditto on the hold-downs being a weak point in the process. I've gotten better luck using the hold-down as well as a Quick-Grip clamp on each end to hold the stock tight to the mortiser table. Makes for a more tedious setup for each plunge, but it's definitely an improvement. I've still got my Delta Mortiser, but have been increasingly abandoning it in favor of the router and a good edge guide.

   Waddaya mean it wont fit through the door?

6. 
   frenchy | Sep 08, 2005 12:58am | #9

   Yogi,

       I use a Mikita chain morticer and except for sharpening a chain I've made hundreds of mortice pockets for my timber frame with it.. thus far never a problem and they sure are fast!  

7. 
   nikkiwood | Sep 08, 2005 04:18am | #13

   I too had a Delta mortiser some years ago, and the hold down was such a PIA, I finally traded it in on a stationary model.

   To what everyone else had said, I would suggest moving back and forth on the first two cuts, plunging about a 1/2" each time. If you are doing a mortise that is 2" long, for example, ordinarily, a stuck bit is problem only with the the first cut.

   ********************************************************
   "It is what we learn after we think we know it all, that counts."

   John Wooden 1910-

1. 
   Yogi | Sep 08, 2005 08:11am | #15

   Little at a time-  Kay-

8. 
   philip | Sep 08, 2005 11:23am | #17

   Yogi, I don't want to harp on about this, but if you can't plunge full depth on the first cut using firm/moderate force there is something wrong. Spraying Teflon etc helps but shouldn't be required. Assuming everything is correctly ground and sharpened and there is suitable clearance the chisel merely shaves the edges of the hole square-too much clearance and the chisel is overworked and the auger can jam at the mouth. Check on that clearance.

   Philip Marcou
1. 
   Yogi | Sep 08, 2005 06:50pm | #18

   Philip-  Harping is good!  And I'll certainly proceed on the premise that proper installation and adjustment should yield design function-  Including but not limited to clearance between the bit and the chisel-  I do appreciate your interest and sharing your experience-  Dave