Problem using Cross stop with Domino

[sroxberg]

I experienced a problem today and don't know why it occured.

I was edge gluing some 80" long cherry boards for a headboard. The first Domino was cut at the smallest setting and the rest were cut on the middle setting.

The first domino was started and registered by the built in pins. I then used my cross stop attachments to put the middle width hole for the rest of the length of the boards.

Both cross stop, left and right, are set on the same scale marking.

I cut about fourteen mortises along the length.

Obviously the distance of the pins on my cross stops were not the same because I had a small variance that multiplied with each new mortise and by the end they were off by a full 1/4 of an inch. I know that the pin was tight and against the prior mortise each time since this happened on multiple boards and the variance was gradually built, you could see it get larger.

What could cause this to happen?

 

[greg mann]

Did you use the same width settings for corresponding mortices?

 

[ejantny]

I had this happen to me a couple of times. I think the problem was in the indexing pin not being 100% in the arc of the mortise.

 

[Wim]

Are you sure you started with the tight mortise at the same side, that is one board from the right and the other from the left. And after each first mortise you changed to the wider mortise and you used the wider mortice at both boards and with the same width-setting.
To check if both pins of the cross stop are set at the same distance, check the distance between the pin of the Domino and the cross stop pin with a caliper or ruler. If both distances are the same, you have a symetrical setting.
If the above mentioned has been checked and double checked, it should be a piece of cake.
Otherwise one of the boards is not really dead and still growing.

 

[Tezzer]

I have doubts on the accuracy of the index pins. You only need a variation of around .4mm each plunge over your 80" to be out that much. Even if the pins are accurate using a bit to much lateral pressure could slightly bend the outriggers .4 of a mil easy.

Dont feel to sad Most seem to dislike the out riggers. You are best to make a quick mark with a pencil.  Below is how i mark mine out. Its simple but it suits me.

When i have a heap of boards and flipping them around to plunge i get confused  : So i put the dot (usualy blue masking tape) on the left and that tells me what side to start with the Domis index pin. That first cut both sides is on the exact setting.

The X board tells me that is all plunged on the exact setting, and that is the side i insert the first row of Dominos.

The O side is the one i plunge on the next lateral setting. That makes for fool proof alignment.

Simple but i never have a problem joining the boards. ;D

[Matty can you get rid of the second photo i accidently posted twice ]

 

[mot]

Thanks for the tip, Tezzer!  I played with the outriggers and instantly thought that they should have been made of extruded aluminum rather than the plastic product, for the very reason of the possibility of flexing them a bit building in error.  Your method is "mot" proof!

Cheers!

 

[Ted Miller]

I did get very mixed up when flipping the boards around as well. I was marking the the edge I started with an E on both boards so I knew exactly what index pin started where. When this first started to happen to me I thought it was just that the adjustable index pin was off then I figured it was the flipping of the boards and also making sure I plunge slow enough that there is zero movement on the domino as its working. I have yet to use the larger mortise selection for extra play. I want all the tenons to fit nice and tight...

 

[Bob Childress]

Read this thread this morning and coincidentally needed to Domino a cabinet carcase today. First occasion to use the limit stop accessory. First set of mortises was off about 2mm, so checked all the measurements, etc. and the next three sets were right on. I have to attribute it to pilot error. Just make sure the pin is in the arc of the mortise. It appears, at least in this case, to be an accurate guide.

I do mark each join with a letter to make sure I am not flipping something the wrong way, which can be confusing. Just one experience. 

 

[rjfarel]

I think Tezzer's success is more due to drinking VB while domining than marking silly lines.

 

[Mark]

Make sure your dust extractor is pulling out all the sawdust from the mortise when cutting. I had my CT22 set to mid range from another job and upon inspection noticed that the mortise had a bunch of sawdust in there.