Replies

1. 
   grousemouse | Jan 08, 2004 07:28pm | #1

   I have really been interested in converting to a slot mortiser.  I have never actually seen one in the flesh.  This one appears to have a drill chuck and be direct drive so I would guess the speed is 3450 rpm.  Is this typical of the European slot mortisers.  Do they cut cleanly at that speed.  Would you use a spiral carbide router bit in the chuck?  From your previous posts it sounds like you have a lot experience with these, any other insights would be welcome.

   Thanks

   Brian

1. 
   rslatm | Jan 08, 2004 10:14pm | #3

   That rpm is pretty much typical. They run from  2,600 to 5,000 rpm.  No need for a screaming 20,000 rpm router.    HSS two flute endmills work great.   No need for carbide.    No need to calculate extra length of stock to compensate for tenons with loose tenons. Perfect alignment of parts everytime.   As long as you reference off the sameface  it's   a    no brainer.   You can keep prepared tenon stock and rip and crosscut as needed.   Not necessary to even r ound the  tenons.     Say you are making making 20 mortises 1/4" x 2"  wide.  Just mark a center line on the pieces of where you want the mortises and reference off a center line on the mortiser.       The down side...it's just too easy and fast! 

   http://www.lagunatools.com/lagunamortiser.asp

   Edited 1/8/2004 4:41:47 PM ET by Rick at Arch. Timber and Millwork

2. 
   Napie | Jan 08, 2004 10:21pm | #4

   The one on my Roland 12" jointer/planner/mortiser is 5500 rpm and with solid carbide metal working spiral bits cuts a near perfect mortise. A little slower should not hurt if the cutter is sharp.  I’m really surprised that it took this long for someone to do this.  Once you use a horizontal slot cutter and loose tennons, you will never go back!  And for $330.00, that beats a big plunge router and the jigs necessary by quite a bit of money.

2. 
   jazzdogg | Jan 08, 2004 09:58pm | #2

   Rick,

   Thanks for the post. From what I can see (the photo is a little small) it looks as though this machine may not have a fence and material hold-down that'll make it easy and fast to register to work and hold it securely while boring holes/slots. I'm also curious about the 3450 rpm speed - my gut says half-speed would be a better bet.

   Paul

   Whether you think you can, or you think you can't, you're right.
1. 
   rslatm | Jan 09, 2004 12:39am | #6

   Paul, the hold down is fine and all you need is that low fence on the edge on the edge of the table. The only thing needed is to make a center line on the fence to reference your pieces. It's good to go as shown in the picture. Been using the same set up for over 20 years  except on different machines like converted handmills or commercial slot mortisers like Griggios, etc.  The  speed is fine. Our Griggio runs around 3,450 with no problems.  Two flute HSS endmills for machining aluminum work real well and cost about $13 and are cheap to sharpen. I found four flutes don't work as good...too many teeth.  There are special commercial type mortise bits but they are more expensive and don't seem to work any better. 

   Edited 1/8/2004 4:43:07 PM ET by Rick at Arch. Timber and Millwork

1. 
   tufenhundel | Jan 09, 2004 02:21am | #8

   If I'd found this product sooner, I wouldn't have made my kludge version.  Since I have an old motor that I took off my tablesaw, I am going to use it in an application like this.  I have several questions for you since you have so much experience with slot mortisers.

   How is the cut affected by a slower RPM compared to a router?  Say, on very porous woods like wenge or oak, does it cause more tear out?  Or is feed rate adversely affected?  I've seen a slot mortiser like this cut sliding dovetails with a carbide router bit, and I wasn't too impressed with the cut.  My suspicion was the slower RPM, so maybe you could verify.

   HHS end mills seems to be the cutter of choice for these machines, but will carbide router bits work as well?

   And what about the 3/4 hp rating of slot mortiser?  I'd imagine it'd be sufficient for this type of work, but to do something similar with a router, would 3/4 hp cut it?

   I guess I have a lot of questions with RPM and power...just want to get my design right the first time.

1. 
   rslatm | Jan 09, 2004 02:48am | #9

   I would have to say you might have to go a little slower in your feed with a 3/4 motor. The ones I've used were 2 hp. No problems with tear out in Oak. Never tried Wenge but I wouldn't expect any problems. Straight router bits don't work as well as spiral cutters I've found. Carbide is just more expensive in an endmill but will last longer although HSS yields an initial sharper edge but carbide would be better for woods like teak. My point is it's an entry level machine and for the money there is nothing close. I'd like to see a bit more power and a tilting table. But if it takes off they might make some changes. Laguna sells the mortiser from the combo machines as a seperate if you call them up but you are talking $500 without a motor. All the shops near me have slot mortisers from the JDS to Rojek, Griggio, SCMI, and half a dozen other models. They all use loose tenons for the most part.

2. 
   robkelly1 | Jan 09, 2004 03:58am | #10

   I've got the Laguna slot mortiser (heavily modified for reproducibility) and use the big 3 hp PC 5-speed (from 10K rpm to 22K rpm) as a dedicated router. 99% of my mortises are 5/16" (cabinets)  or  1/2" (entry and passage doors, all 7/4). I use 2-flute carbide straight bits,  and run them at the 22K speed in oak, walnut, alder, mahogany and cherry. I never take > 1/2" or max. 3/4" bite. If the router goes, I'll replace it with a single speed. I've never broken a 1/2" bit but I did break a  5/16" Bosch extra long bit on the 2nd pass which I sent back and they replaced. I like the straight bits because I can sharpen them with a diamond file.

1. 
   tufenhundel | Jan 09, 2004 08:33am | #12

   rob:

   Using a router was the original design and it works well enough.  But since I had a good 1.5hp motor gathering dust, I thought I'd convert the design to use this motor.  The "motorvation" (sorry, couldn't help it) for this is the much lower noise level of the induction motor, and the fact that I can run it all day long.  Plus I could improve dust collection with a redesigned arbor assembly (not encumbered by a mounted router).

   The design question now is the pulley sizes to step the RPM up higher.  If a machine running @ 3450 RPM is sufficient, then my thinking is that 10K RPM would be better, mainly for cut quality.  And I would not have to go to 20K, as a router does.  It simplifies the design greatly.

   I think I've learned enough from this thread to keep RPM to ~10K.

2. 
   JohnWW | Jan 09, 2004 12:40am | #7

   The picture I've seen, on their web page, shows a large vertical bar supporting an arm with a cam clamp for a hold down.  As is typical on the European machines, the only fence appears to be a small raised lip on the front edge of the table.

   John W.

3. 
   TomMGTC | Jan 08, 2004 10:35pm | #5

   Looks interesting. The table travels aren't enough IMHO but it is a start. For those that haven't used a machine like this it is hard to beat. For example I just cut 100 mortises in cherry 3/8 x 2 x 7/8 deep. 80 of them were angled 10 degrees. Total time including setup took 50 minutes. Thats well undr 30 seconds per mortise and the resulting mortises are perfect. I use a home built router based slot mortiser.  

   Tom

   Douglasville, GA

4. 
   Scrit | Jan 09, 2004 07:41am | #11

   A couple of questions. Is this actually a slot mortiser? It seems to lack the 3-axis motion lever I normally associate with slot mortisers. Also does it have the necessary side thrust bearings that you need for slot mortising? If not, surely it will run its bearings quite early. Finally, as someone else pointed out 3450 rpm seems a tad slow for slot mortise bits - though they were designed to run at 5 to 8,000 rpm? Looks like it will make and excellent low-cost horizontal borer for chairmakers, though

   Scrit

   
   

   ---

   Edited 1/8/2004 11:44:48 PM ET by Scrit

1. 
   rslatm | Jan 09, 2004 07:24pm | #13

   Scrit...if you look at the description of the G0540 it clearly states that the table has 6" of side travel. That spells slot mortiser to me.  As far as rpm...speaking from actual experience 2,600 to 5,000 works fine and if you check with the specs of  commercial machines you will see that they fall into the same rpms. It seems that this machine is so new at Griz they don't even have them in.  Many of the commercial mortisers use direct drive motors to power their machines.  For $330 I'd buy the Griz G0540 mortiser in a heatbeat if I needed one.  You couldn't cobble something together for that price.

   I've included some links for all the skeptics about rpms.  Been using the systen for years so I'm sold. Just trying to pass on some info to help others. You can try what ever tooling you like but I'm sure you'll find something that works.

   http://www.lagunatools.com/lagunamortiser.asp

   http://art.sdsu.edu/geninfo/homepages/furniture/facility/mortiser.htm

   http://mypage.uniserve.ca/~kristech/page18.htm

   http://mypage.uniserve.ca/~kristech/page18.htm

   http://www.atlanticmach.com/standard/misc.html

   http://www.casadeiamerica.com/model_response.asp?Category=Slot%20Mortiser

   http://www.carolinawoodworkingconsultants.com/specsheets/invicta/Invicta%20FI-15-3%20Mortiser.doc