Did I damage my 6mm cutter head? Pic attached

[johnsayen]

Hello,

Only have around 50 mortises cut with this 6mm cutter - ordered a replacement as I believe I damaged it while using it. I noticed that all of a sudden my dominos would no longer fit in the holes, like it was very slightly too small.

Attached a picture compared next to a 5mm - is it indeed damaged or am I missing something totally obvious? It is shorter than the 5mm which leads me to believe it is.

Thank you.

 

[Birdhunter]

Yep, got it good.

 

[Michael Kellough]

Trashed.

 

[ChuckS]

Assuming there's no hidden metal in the wood, to prevent this from happening:

1) Plunge slowly/steadily (if you hear wood chattering sound, the plunge speed is too fast)
2) Withdraw slowly, and do not move the machine until the bit is withdrawn.

If the spinning cutter (tip) touches the wood (cavity) while withdrawing, the chances of breakage increase. That's especially true with the smallest cutter.

Of course, dust extraction should be used for all mortising operations. 

 

[rst]

I was having trouble getting my 6mm dominos in, not by much but annoying, was sanding them down.  Finally occurred to me to check the cutter with magnification, smallest nick off the ends was missing. I now keep spares (CMT) and have not since had trouble or had to replace.

 

[Rick Herrick]

1) Plunge slowly/steadily (if you hear wood chattering sound, the plunge speed is too fast)

I agree with this 100%.  I think this is the single most important thing you can do to ensure success with the Domino.  I got reminded of it just a couple of days ago.

 

[sancho57]

Yup time to give it a Viking funeral

 

[johnsayen]

Assuming there's no hidden metal in the wood, to prevent this from happening:

1) Plunge slowly/steadily (if you hear wood chattering sound, the plunge speed is too fast)
2) Withdraw slowly, and do not move the machine until the bit is withdrawn.

If the spinning cutter (tip) touches the wood (cavity) while withdrawing, the chances of breakage increase. That's especially true with the smallest cutter.

Of course, dust extraction should be used for all mortising operations.

Thank you, it was definitely operator error, in that I was trying a cut from a strange angle and I must have knicked the cutter while withdrawing. Only a few holes left and now I'm hung up on this project. I think I'll order a second spare right now.

 

[ChuckS]

For those few remaining mortises, could you use 5mm dominoes? It may take days (longer if by mail) to get a new cutter. In a few times, I ran out of dominoes and used the next size (down or up).

 

[Mike Goetzke]

1) Plunge slowly/steadily (if you hear wood chattering sound, the plunge speed is too fast)

I agree with this 100%.  I think this is the single most important thing you can do to ensure success with the Domino.  I got reminded of it just a couple of days ago.

I see this mentioned all the time but I use lots of oak and no matter how slow I plunge I always feel some chatter. Is there a better technique to work on? - Thanks

 

[johnsayen]

For those few remaining mortises, could you use 5mm dominoes? It may take days (longer if by mail) to get a new cutter. In a few times, I ran out of dominoes and used the next size (down or up).

Unfortunately I can't, as I already mortised one side of the joinery. I thought about stepping up to the 8mm cutter as I have one on hand, but the material is only 16mm thick and I'm concerned about strength/the rule of thirds. I guess I could fill the 6mm holes on the one side with tenons and glue, cut them off and sand them flush, then re-mortise with 5mm. The new cutter will not be here until Friday - oof

 

[Rick Herrick]

I see this mentioned all the time but I use lots of oak and no matter how slow I plunge I always feel some chatter. Is there a better technique to work on? - Thanks

I am by no means an expert.  Been using the Domino only for a couple of months.  Every time I make a bad plunge, I can pretty much see why it happened.  I guess the amount of 'chatter' is pretty subjective.  I guess even the best plunge ever still makes some degree of chatter/noise. 

I just made 6 hard maple doors (following the recent Sedge video on Domino doors).  The second plunge I made, made a lot of noise and the hole was ragged as can be.  But I refocused on my plunge speed and things improved greatly.  I was using the 8mm bit and my plunge time is about 5-6 seconds.  I don't make a living doing this so I can go slower.

 

[johnsayen]

For those few remaining mortises, could you use 5mm dominoes? It may take days (longer if by mail) to get a new cutter. In a few times, I ran out of dominoes and used the next size (down or up).

Unfortunately I can't, as I already mortised one side of the joinery. I thought about stepping up to the 8mm cutter as I have one on hand, but the material is only 16mm thick and I'm concerned about strength/the rule of thirds. I guess I could fill the 6mm holes on the one side with tenons and glue, cut them off and sand them flush, then re-mortise with 5mm. The new cutter will not be here until Friday - oof

I double checked the thickness, it's actually 19mm. Do you think I'm pushing my luck by bumping up to 8mm for the last few joints? The material is hard maple.

 

[ChuckS]

Pushing luck -- not at all. I'd do it even if it were 16mm in thickness unless some specific joinery strength is at stake. The 1/3 rule applies more to softwood than hardwood, and is a guideline only. I break it now and then with no negative consequences or failures.

For 3/4" (19mm) lumber, the manual says 8mm dominoes are totally acceptable. They're what I normally use for hardwood stock unless the build is light weight.

 

[johnsayen]

Pushing luck -- not at all. I'd do it even if it were 16mm in thickness unless some specific joinery strength is at stake. The 1/3 rule applies more to softwood than hardwood, and is a guideline only. I break it now and then with no negative consequences or failures.

For 3/4" (19mm) lumber, the manual says 8mm dominoes are totally acceptable. They're what I normally use for hardwood stock unless the build is light weight.

"...when the width of the Domino tenon is relatively narrow compared to the width of the joint."

hmmm. 8x40 Domino is 22mm wide, and the joint is 38mm, I think I'll do a test joint first.