How to Shortening Doors ??

[Dave Ogren]

I am usually over at the Turners Forum, but now I have a new problem that isn't related to turning and need some advice.

I have just put down slate on some of the floors in my home. Now I am going to have to shorten 19 doors. These are hollow core doors and I do not know the proper method for doing that. I don't want to replace them because they have been finished perfectly to match the rest of the home and they are also 8' tall, and I would think special (expensive).

Do I cover the cutting area with masking tape or ?? I do not have a table saw, just a couple of Makita circular saws. What kind of a blade do I need to use, etc ??

Thanks in advance for your help.

Dave

[Harley Lewis]

I am certainly not a professional, but I have shortened a lot of doors. I used a simple skill saw with a fine tooth blade, clamped a straight edge on the door as a saw guide and cut away the excess. I guess taping the cut would make for a finer edge when done, but I never did do that and it worked just fine. I just sanded the cut edge and wiped on a bit of finish and put them back up. Be sure you seal the raw cut.

[Kent A Bathurst]

I am usually over at the Turners Forum, but now I have a new problem that isn't related to turning and need some advice.

I have just put down slate on some of the floors in my home. Now I am going to have to shorten 19 doors. These are hollow core doors and I do not know the proper method for doing that. I don't want to replace them because they have been finished perfectly to match the rest of the home and they are also 8' tall, and I would think special (expensive).

Do I cover the cutting area with masking tape or ?? I do not have a table saw, just a couple of Makita circular saws. What kind of a blade do I need to use, etc ??

Thanks in advance for your help.

Dave

Oh - the miseries of flatwork. Yes - I'd use "blue tape" on both sides, and use a straight-edge as a guide, and find something the same thickness as the door to use on the other side of the blade - you don't want the circle saw tipping.

You don't say how much needs to come off the doors - keep in mind that the rails at the top and bottom might be as narrow in height as 1" (but I'd guess closer to 1-1/2"). Carbide blade, lotta teeth. If you want to go whole-hog, go to Forrest Mfg site, and look at the Duraline Hi-A/T. GULLLLP!! I only use Forrest, but there will be about 100 guys jumping in here shortly that think there are better or just-as-good blades for less - they might be right - I wouldn't know.

Don't know that there is an in or an out, but with the circle saw, "good side down" is the rule for cleanest cut - but with the tape and a good blade, prolly won't matter. If it's a closet, for example, cut that door with the "outside" down.

There are also these things the rest of us call "handplanes", but with a one-timer and 19 doors to do, that doesn't seem like the way to go about it.

[David G Baker]

I had to cut off 6 hollow core doors and fill the bottoms in due to the bottom fill was not long enough to cover the cut. What I do is use the blue tape on both sides of the door, take a T square and a box knife and score my cut line on both sides of the door, then make my cut using a fine tooth blade on a circular saw against a firmly attached straight edge. I used soft pine as the filler for the opening at the bottom of the doors. Had I known in advance what a big pain it would be I might have purchased solid core doors.

[Bob Vavricka]

+1 for what David said about scoring both sides before cutting or at least the top. It helps keep the top face from splintering. If I cut the entire bottom filler off, I just clean the plywood faces off with a chisel and glue the filler back in. I would also recommend putting finish on the cut bottom surface.

[Tony Shea]

I've often used flush trim router bits and a router and used a wooden straight edge clamped to the door. Make sure you clamp a block on the end of the cut to prevent tearout, maybe masking tape would be fine.

[Stephen Edwards]

I've done this many times over the years. Depending on how much material you'll be removing from the bottom of the doors, you may or may not completely cut out the bottom filler piece. If you're lucky, you won't. If not, you'll have to deal with that, too.

There's more than one "right" way to do this. Other people have given you good advice. To that I would offer this:

If I had 19 of 'em to cut off, I'd make a jig that serves two purposes: it provides you with a surface for the saw to travel on top of (reducing the chance of scratching the finish on the doors) and it provides you with a straight edge (think fence) for the edge of the saw to ride against.

This jig can be made of a scrap piece of hardboard or plywood for the platform and one piece of 1/2" or 3/4" tall plywood or milled stock, on top of the platform. I'd make that top piece (the fence) wide enough so that you have enough room to clamp this jig to the door on both ends of the jig and clear the saw's motor. You could even add a piece on the starting end of the jig, under the platform, that acts as a square when set against the side edge of the door.

I'd also make the jig so that the wider part of the saw's table, platen, platform, whatchamacallit is riding on the jig platform. For most saws that would be to the left of the blade.

Test it on a piece of scrap to make sure that you have measured the correct distance from the inside edge of the blade to the jig fence. When you're sure of that you simply measure from the bottom of the door to the cutline and clamp your jig's platform on the cutline. If all of the doors are going to be cut off the same amount you can make a little gauge and not have to measure at all. The edge of the jig also serves as the straight edge for scoring the top side of the door.

It'll take about 30 minutes to make the jig and will save you a LOT of time when sawing the doors down to the correct height.

Good Luck with your project!

[Erik Christensen]

and it is absolutely perfect for that task - you can shave the door 1/16 at a time if you want and each cut is perfect and splinter free. I have done solid interior & exterior doors along with hollow core with equally good results

skill saw with fine tooth blade, masking tape & straight edge would also work - just takes more skill than i have to do a consistently good job

final tip is one I learned from John Lucas - get a 4x8 sheet of rigid Styrofoam insulation to use as a cutting base - it helps reduce tear out on the bottom side

good luck - 19 is a whole lot of doors - whatever method you choose you'll be really good at it by the time you get done

[Peter Quinn]

My method is similar to Stephen's, except i allot about 5 minutes to make the jig. Id use a piece of 1/2" material, MDF or birch plywood if you have it, something flat. You need a piece about 10" wide and a bit longer than your widest door. You also need a strip of 1/4" material, MDF or masonite works fine, ripped about 4" wide. A basic makita skill saw has a blade to edge of plate distance around 5 1/4", so if you butt one edge of the 1/2" material and 1/4" material and staple or brad nail them together, this gives about 6" left. The 1/4" material is the fence. Don't be fussy, just get it in a straight line.

Pass the saw through the jig once, and you have a precision straight edge that will give you 1 3/8" depth no problem, can be clamped to your door (the 10" width leaves space for the saw's motor to pass over a set of small c clamps), and creates a ZCI situation that will minimize ship out. I'd still cover the TOP surface with blue tape as masonite can be unpredictable especially if it is textured. The jig also indicates exactly where the saw will cut, so no crazy measuring the off set is required like a basic straight edge.

If you cut the strip out of the bottom, or cut so much off that whats let is weak, just mill some pine or poplar to fill the gap and glue it in, a few clamps to set it or pin nails work well. I use a fine cross cut thin kerf Freud blade on my 7 1/4" makita and it works well in both masonite and hardwood. I did 8 masonite doors this summer this way, no problem. You can tape the bottom of the cut too if you seem to have issues, but that side won't normally chip out.

[Rick Moyer]

19 doors over slate!!? What, are you living at the Biltmore Estate?

[Walter Plummer]

I also use Stephen`s type of guide, but make it wide enough so your first cut cuts off the edge of the base of the guide. Then that edge is exactly where your saw is cutting. If they are flat slab doors mark the bottom with tape before you take them down. I have heard that sometimes the top gets cut by mistake. I type to slow. Peter beat me to it.

[Dino Makropoulos]

Do I cover the cutting area with masking tape or ?? I do not have a table saw, just a couple of Makita circular saws. What kind of a blade do I need to use, etc ??

Thanks in advance for your help.

Dave

Dave,
What you need is a zero clearance sub- base for your circular saw
(You can make one from plastic)
and a straight edge to guide your saw.

To eliminate the offset measuring, screw 2 strips of wood to the straight edge and trim the strips.
Or, make the straight edge wide ( like said above) and trim the straight edge.

good luck.

[Dan Friedrichs]

I know you said you didn't want to replace them, but you might look into the cost, anyways. I've seen surplus places selling them for $10/ea.

[Loren Bengtson]

I had to cut off 6 hollow core doors and fill the bottoms in due to the bottom fill was not long enough to cover the cut. What I do is use the blue tape on both sides of the door, take a T square and a box knife and score my cut line on both sides of the door, then make my cut using a fine tooth blade on a circular saw against a firmly attached straight edge. I used soft pine as the filler for the opening at the bottom of the doors. Had I known in advance what a big pain it would be I might have purchased solid core doors.

My dad was a professional carpenter/general contractor. He used David's method. I never saw him take so much off a door that he needed to fill the hollow core, though.

Score the plywood veneer with a utility knife, cut just outside the score line with your circular saw with the finest-tooth blade you own.

That fine-tooth blade is not absolutely necessary. My dad owned only one blade for his Skilsaw and used it for everything, including shortening doors.

For what it's worth, he was the best freehand Skilsaw operator I ever saw. He told me that when he apprenticed as a carpenter he sometimes had to rip 2x6's at a miter with a handsaw. I think he bought the first Skilsaw he saw and used it a lot.

Good luck,
Loren

[Myk Rian]

I just replaced 5 doors in the house, and had to trim 2 of them. A straight edge and a circular saw with a $9, 30 tooth Diablo blade did a fine job.