Thin Strip of Material at End of Tenon

[Chris Larson]

Hello All,

What is the deal with the thin strip of material we get at the end of our tenons on a consistent basis? Sometimes it comes off very easily or simply gets crushed inside the joint once two parts are put together, but often times we see our guys on the shop floor knocking these strips off of every part with a sanding block. This is very time consuming considering the amount of parts we process every day. Any hints on why this occurs or what we can do to eliminate it?

Thanks,

[Daniel Odom]

Use a larger diameter tool for the tenons by listing your rout/dado tools in order of largest to smallest diameter in your tool setup @ the machine. You may have to adjust your tenon thickness or depth/tenon length depending on your tooling setup.

[Chris Larson]

Thanks Daniel,

These tenons are being cut with as large a tool as possible. My tenon length is set at .376" (so it can be cut with a 3/8" tool) with a .02" depth clearance. This consistently results in a sliver of material on the end of the tenons that is maybe .01" +-. It's not a huge deal, but sometimes it does need to be dealt with pre-assembly. When you are processing 400 parts a day, it becomes in issue. Does anyone else have this problem?

[Josh Rayburn]

Hi Chris,
That happens because the boundary of the dado operation created by the length of the tenon is EXACTLY the same width as the tenon length that you specify. Unfortunately, there's no option to change that behavior at this time. I've asked previously to have this addressed.
At least I would appreciate the ability to over-cut the tenon length (outside of the part) by .01" (at least) and also allow me to surface a short tenon with a larger diameter tool as long as it won't hit an adjacent part. I don't know if either one of these requests are in the works or not.
jnr

[Chris Larson]

Thanks Josh. I remember now that you explained this to me once quite a while ago. It seems odd though that this left over material is just considered typical. Do any Thermwood people have anything to say on this subject?

[Josh Rayburn]

Chris,
Yep I've explained this to lots of people over the years, so you're not alone in your frustration. I've never really seen a response from TWD on the subject. It would be nice to see a fix implemented!
jnr

[Daniel Odom]

Can't say I've had this problem, I don't think I have any special settings, usually just use 50% of mat. thickness and .375 deep with .015 depth/fit clearance. I use the same .375 diameter comp. tool for dado, tenons and outlines in most cases.

[Forrest Chapman]

You are definitely not alone. We have asked for this feature for nearly 10 years now. As Josh knows our "other software" handles this operation with ease. There is no reason that a larger diameter tool cannot be used to mill the tenon to thickness. This tool can be handles automatically or by way of an extra tab in the tool settings.

Forrest

[Chris Larson]

Update:

I have tried Daniels setting of .375" tenon and a .015" depth clearance as opposed to my previous setting of .376" tenon and .02" depth clearance. Since I have made these adjustments we have noticed significantly less of the fuzz/ leftover material issue. I had been concerned that a 1/4" tool would be selected to cut the tenon, but it was not. The tenon was cut with the 3/8" tool. My only remaining concern is that .015" depth clearance may not always be enough and may obstruct joint closure if there happens to be too much glue or debris in the dado. So far so good though. Thanks Daniel & everyone else for your input.

[Josh Rayburn]

Hi Chris,
I'm surprised, in the old days we had to be sure that the tool was at least .001" smaller than the operation we wanted it to perform, i.e. the dado, pocket, etc.
I guess that's changed now, so that's great!
We run a .02 depth clearance - also because the material could vary in thickness from sheet to sheet. If you had a unit come in thinner than you programmed, then the tenons could bottom out before you get the joint closed. Sometimes you even get a single sheet with more than .015" variation from one end to the other. It's not usually that extreme, but it's a pain to fix it later, so we run the extra depth clearance to make sure it isn't a problem.
jnr

[Chris Larson]

Hi Josh,

It also occurred to me that, theoretically, the length of the tenon and the fuzz on the end of it should not be affected by the depth clearance value. So, I guess I will try a .375" tenon with a .02" depth clearance because after all ... that is what I am looking for!

Looking forward to the Craftsman Ale House one night!