Router bits getting too hot on hardwoods


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Being I am "still learning" I was hoping for some advice on routers as I narrowly missed a very expensive "greenhorn" mistake yesterday.

I was playing with some walnut to make a 2" wide sliding dovetail for my cabinets drawers and heated my brand new bit bad (it was only 8 dollars). I know I made a series of compounding mistakes but it does lead me to a question (not the same mistake as above).

I am going to start on my bread box and it will be made out of purple heart. I have the patterns set up to make all the groves now just have to build and router.

I will have a brand new router bit which will be sprayed with blade coat before I begin and during. I could only get a 1/4 inch shaft and will be using the router not the trimer. I know I need to make very shallow cuts but I don't want to end up burning anywhere as that will bring out a very deep purple that is hard to get out.

Typically I run the 1/4" shaft at 3/4 speed max but was curious if I should be going to full speed, I am hoping to get the bit to last, I will have 4 seperate cuts to make. This is a 1/2" cut top bearing bit.

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21 minutes ago, wdwerker said:

Clean out the middle of the sliding dovetail slot with a straight bit before you cut the dovetail profile. 

Thanks for that, actually solves that riddle for me.

 

24 minutes ago, Brendon_t said:

Purple Heart in my experience does two things,  Burns, and splinters. 

I will be paying very close attention to the board when it comes through the planer and will plan and arrow the layout to minimize the splintering, should have that problem worked out, just need to figure out the router speeds and depth.

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One of the best things you can do is get quality bits. Using a router with cheap bits is just begging for problems in my experience. I normally recommend Whiteside (my preferred), Eagle American, Freud, CMT, etc. There's a number of makers of quality bits out there.

I do keep around one of those super cheap $100 router bit sets from the home center that includes a whole bunch of profiles that I typically never use just on the off chance that something odd comes up and I need a certain bit quickly. Typically though, as soon as I start planning for a project I'll pick up premium bits in the required profiles and just plan for it as part of the cost of the project.

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9 minutes ago, Still learning said:

8 dollar ones are great for practicing and learning mistakes  :D

The bit I bought for this particular piece is a freud. I wanted a 1/2 shaft but couldn't find one in Canada.

Pretty sure we have 1/2" shaft router bits in Canada.

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3 hours ago, Eric. said:

I thought you said you were making sliding dovetails?

no I have to make a bread box and it has to be purple heart to match the cabinets.

I bought a dovetail bit for 8 just to play, cost me 8 and a post and figured that problem out, now I understand how that works.

I was hoping someone could help me with speeds to get through the straght cut on the purple heart.

3 hours ago, drzaius said:

For top bearing 1/2" bit you'll have to go with 1/4" shank cause the bearing, which is 1/2" OD has to fit over the shank. Bottom bearing 1/2" bits can be had with 1/2" shank.

thanks, never thought of that, made a wrong assumption

Edited by Still learning
accidently hit submit on tablet
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19 hours ago, Still learning said:

Typically I run the 1/4" shaft at 3/4 speed max but was curious if I should be going to full speed, I am hoping to get the bit to last, I will have 4 seperate cuts to make.

Just the opposite. If you're experiencing burning, you need to either slow down the rotation speed or increase the feedrate.

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10 hours ago, micks said:

Just the opposite. If you're experiencing burning, you need to either slow down the rotation speed or increase the feedrate.

Thanks Mics,

Turned it to 1/2 speed, did 1/4" depth in 4 passes and no burning that cant be sanded out, greatly appreciated tip.

9 hours ago, drzaius said:

A quality bit will have no problem lasting the 4 cuts & many more.

Just to be clear, you are buying carbide bits right?

Freud bits, I got a set of Yoniko shaker door bits for my birthday and was pleasently surprised on how nice thy cut. I only get cheap ones to practice with. I have a theory,  if you can make a shitty one work decent you can get a good one to be better.

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router speeds usually have to do with the size of the bit you're using. The bigger the bit the slower the speed. When I'm routing a small profile on, hard maple for instance, I'll crank the up the speed and run the router a few light passes carefully towards me and take the finally cut with a steady pass the "correct way" (against the spin). That way I avoid chip out and burning the stock. 

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Pulling the router towards you or in the "wrong direction" is also called climb cutting. You need to be very careful and not try to take off too much material in one pass . Practice this technique on soft woods and don't try it if you don't have a steady hand and some self confidence. Too much pressure will cause the router to rush towards you alarmingly fast. Having said all that it can yield better results in some grain patterns.

Bits with 2 distinct wings are more risky to use this way. Bits that appear almost circular with a slot before the cutting edge are much safer as they limit the amount of material the bit cuts on each revolution.

 

 

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Thanks wdwerker - another part to this question, I built a router fence out of walnut (cabinet door I made) it is on a track system.

I want to cut some dovetails through the thickness of a 11/2" board, is it better to pull the fence with board clamped to it into the bit or to push it into the bit?

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