LumberJocks

Miters to join a Cross

  • Advertise with us

« back to Joinery forum

Forum topic by kocgolf posted 11-12-2017 04:50 AM 534 views 0 times favorited 17 replies Add to Favorites Watch
View kocgolf's profile

kocgolf

268 posts in 2017 days


11-12-2017 04:50 AM

I am making a prototype of of a Cross for our church. Mainly because I KNOW that the joinery will be very difficult. Or at least it will be for me. I assume with the 8 miters joining in the center that it’s going to be quite tedious to finesse it tight and aligned, especially with there being a profile around the entire outside.

Who has done something like this, and do you have any tips? What would be the best practices to get the joint tight on all sides? I have a miter saw and a miter sled for my tablesaw, but I don’t have a shooting board or really a plane that would be great at it.


17 replies so far

View jonah's profile (online now)

jonah

1471 posts in 3138 days


#1 posted 11-12-2017 12:10 PM

Why miter it at all? I’d just make it out of two pieces instead of four and use a half lap joint there in the middle.

View kocgolf's profile

kocgolf

268 posts in 2017 days


#2 posted 11-12-2017 01:27 PM

It may come down to that, but I would like to try and make it work. It would then match the large cross that hangs over the sanctuary.

View bondogaposis's profile

bondogaposis

4482 posts in 2190 days


#3 posted 11-12-2017 02:05 PM

Miter joints are very weak, 8 of them coming together like that would likely be a disaster unless you have a plan to reinforce them some how. I’d half lap them, like jonah said.

-- Bondo Gaposis

View hairy's profile

hairy

2586 posts in 3371 days


#4 posted 11-12-2017 03:07 PM

I did something similar, though not as finished as yours will be.

I save scraps of T track. When I get enough I will make an assembly jig with T track and plywood. I used a home made miter jig to cut the track.

This piece is a test of the joints.

It is a little rough, but for my purpose it can be.

I started out cutting 1 miter, then using the other side of the jig to cut the other angle. I guess my jig isn’t dead on accurate. There is a slight gap in 1 of the joints, top left. I then cut both miters on the same side of the jig, just cut and flip it over, and had good results.

I agree about the half laps. Maybe you could half lap and then veneer the surface with miters.

-- My reality check bounced...

View JBrow's profile (online now)

JBrow

1275 posts in 759 days


#5 posted 11-12-2017 03:10 PM

kocgolf,

I have not brought four pieces together with a mitre joints, but I have some thoughts that I hope are helpful…

One method for obtaining tight fitting mitres that join well in center of the cross would be to cut complementary mitres in the adjoining spokes. Even if the angle of one mitred piece is not quite 45 degrees, the adjoining spoke would be a little more than 45 degrees and the two mitres, when brought together, would form a 90 degree angle.

These complementary mitres could be cut with a mitre sled built for the table saw. It would consist of a flat base (MDF would be a good choice) on which the work pieces rest during the cut. Runners that guide the base during the cut would use the mitre slots of the table saw. The mitre sled fence could be a single or double layer of ¾” plywood or MDF and would be fastened to the base. The fence would require two edges that intersect to be a perfect 90 degree angle. The fence would be fastened to the sled’s base so that the edges that form the perfect 90 angle are set as close as possible to yield a to 45 degree angles to the saw kerf in sled’s base when the work piece is cut. However, this 45 degree angle does not have to be exact. Some sand paper glued to the fence and/or base would help keep the work pieces from shifting during the cut, but clamping the work pieces in place before the cut is perhaps best. I would be inclined to add sand paper and also use clamps to secure the work piece to the sled.

One work piece would be positioned on the right side of the mitre sled while the work piece that joins this first work piece is cut on the left side of the mitre sled. While the mitres in these two pieces may not be exactly 45 degrees, when joined together the two mitres would form a perfect 90 degree angle.

A sharp, crosscut saw blade that yields a clean cut could allow glue-up without any further work. Leaving the spokes long until the cross is assembled and then cutting the spokes to length would allow mitres in the work pieces to be cut several times until a perfect and clean mitre is obtained.

I too would be worried about the strength of the joints. Therefore looking at ways to reinforce the joints might be worthwhile. Floating tenons, biscuits, splines or dowels come to mind, but aligning the pairs of pockets (mortises, slots or holes) to achieve faces that are flush could be a challenge. A more difficult but very strong joint that is easier to glue would be mitred lap joint. This joint would require some planning and practice to accomplish and would leave only one face mitred. The opposite face would feature what would appear to be butt joints. I mitred lap joint could not be used if the work pieces are less than 1” thick but over 1-1/2” would be better for this mitred lap joint.

The glue-up would be a challenge for me. I would be inclined to build a clamping jig that is finished with polyurethane and waxed to keep from gluing work pieces to the jig. The clamping jig would be designed to hold the work pieces in position while clamping pressure is applied to bring the joints together.

View jonah's profile (online now)

jonah

1471 posts in 3138 days


#6 posted 11-12-2017 03:13 PM

I like the veneer idea. You could also carve miter looking lines into the front of the cross.

View kocgolf's profile

kocgolf

268 posts in 2017 days


#7 posted 11-12-2017 07:23 PM

I really appreciate the slew of detailed advice! I should have been more clear that, YES, I will be re-enforcing the joints. Likely with splines, maybe even borrow a friends domino.

I hesitate to learn veneering for this, but I do think I have come up with a method that will alleviate the need to do all 4 (8) miters joining in the center. To match the current cross, I am adding a band of walnut through the middle of the cross going in each direction. I think this will allow me to assemble each side/wing of the cross separately with the spline in them, and then join the sides together at the center with the long vertical spline. I could even joint the center faces before sandwiching in the vertical spline in final assembly to tweak any small angle mistakes. The two vertical cross halves in each side assembly will be weak, but I will re-enforce.

We’ll see how the test goes.

View Madmark2's profile

Madmark2

373 posts in 427 days


#8 posted 11-12-2017 07:59 PM

Half-lap the main cross. Groove the cross and miter in some nice inlays. Trim the ends and route the outside. Easy & fast to make, hard to screw up.

M

View Jim Finn's profile

Jim Finn

2577 posts in 2761 days


#9 posted 11-12-2017 09:39 PM

I have made a few crosses like the one here. What I do is hot glue (temporally) the two pieces together and then cut them diagonally on my miter saw. I then glue the two parts (IE. top and right side together as one part and the other two parts together also). After the glue sets I true both assemblies up on the miter saw and then glue them together. This is a weak joint so I glue a 1/8” piece of wood the the backside to hold this joint together.

-- No PHD, but I have a GED and my DD 214

View kocgolf's profile

kocgolf

268 posts in 2017 days


#10 posted 11-12-2017 11:15 PM

Jim, that is kind of brilliant. I think I will do a couple test runs and see what works best. I’m not sure if that method will work for this particular cross as I would need to add this raised/proud walnut spline in the center of each section before cutting miters with your method, but I don’t know how I would get them to hot glue, lay flat and flush with that sticking up. Going to give it a shot with some scrap though. It’s a super great solution!

View Jim Finn's profile

Jim Finn

2577 posts in 2761 days


#11 posted 11-12-2017 11:23 PM

I am not sure if this will help… but I have also done this with other crosses like this one . It may not be what you need but this method worked for me on this. No 1/8” backing on this one though.

-- No PHD, but I have a GED and my DD 214

View dalepage's profile

dalepage

317 posts in 680 days


#12 posted 11-13-2017 01:17 AM

Do the absolute best you can to hit the miters dead, solid perfect. On the last piece, you can custom cut the angle to account for that fraction of a degree off of your 45. Before you cut the last piece to length, shim the far end with paper and cut the 45 until it fits perfectly. Now cut it to length. No one will see the difference.

-- Dale

View kocgolf's profile

kocgolf

268 posts in 2017 days


#13 posted 11-13-2017 01:22 AM

Thanks again Jim!

Dale, your suggestion was exactly my first plan. Cut the first three, leave the last a little long, and finesse that last custom angle over and over until it’s close enough to pass. It’s going to finish up stained a nice boring golden oak, so a little teeny tiny dab of putty won’t kill me either. Hoping I won’t have to resort to that though.

View jbay's profile (online now)

jbay

1859 posts in 738 days


#14 posted 11-13-2017 01:41 AM

You should put a plywood spline in the center of them.
Cut the grooves before you cut the miters would be best.

-- If anyone would like to see my Portfolio, PM me and I would be glad to send you the link.

View Rick_M's profile

Rick_M

10640 posts in 2219 days


#15 posted 11-13-2017 02:45 AM

I would make the vertical a single piece and half lap miter the sides.

-- http://thewoodknack.blogspot.com/

showing 1 through 15 of 17 replies

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com