# Testing shop made dovetail cutter



## Chuck K (Dec 16, 2020)

I've made several tool holders for my lathe. I've always used HSS dovetail cutters and it seemed to take way too long.  I've seen tutorials on YouTube where they make indexable carbide cutters. I have a bunch of inserts that I had no use for, so it seemed like a good project. After I finished it, I made a holder and was impressed with the way it cut.  I didn't push it real hard.  I was advancing 0.025 per pass.  That was more aggressive than I do with a HSS cutter.  Today I decided to see what it could do.  I finished the holder in three passes. 0.100, 0.100, and 0.037. It seemed to handle it fine.  I'm impressed. The material is 4140.


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## Winegrower (Dec 16, 2020)

Nice work.  I made a couple of dovetail cutters but with only one insert each...fearing I would never get the tracking correct.
The only issue I encountered is that the inserts I used were on the small side, and made it a bit more difficult to cut deeper dovetails.
I will just have to make more.


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## Chuck K (Dec 16, 2020)

I made one a few years ago that had three inserts.  I didn't locate the screws well and the inserts kept working loose. It was a failure.


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## silverhawk (Dec 16, 2020)

So how did you align the screws this time for success? What made the difference on this iteration?

joe


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## Chuck K (Dec 16, 2020)

I took a short piece of 3/16 round and turned the end down to 0.128.  That fit tight in the insert hole. I put a 30 degree taper above it so it sat in the insert perfectly. Then I mounted it in a collet in my mill and positioned my insert with it. When I had my position, I spotted, drilled, and tapped it. Rotated 180 and repeated.


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## Jim F (Dec 16, 2020)

How much does the insert extend out and down ?


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## Chuck K (Dec 16, 2020)

I couldn't tell you without measuring it.  I just eyeballed it.  I could measure it when I get a chance.


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## Jim F (Dec 16, 2020)

Chuck K said:


> I couldn't tell you without measuring it.  I just eyeballed it.  I could measure it when I get a chance.


No hurry, climate prevents shop time right now.
Would like to make one of those, though.


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## rwm (Dec 16, 2020)

Remarkable how your inserts meet perfectly at the center! Nice work. I made a single cuter insert that just worked OK. I guess I need to revisit that.
Robert


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## Chuck K (Dec 19, 2020)

Jim F said:


> No hurry, climate prevents shop time right now.
> Would like to make one of those, though.


I was in the shop today and was going to get measurements for you. Short of taking the time to set it up to measure it with a height gauge, I don't know how I would do it. I basically just positioned the insert a little proud of both the side and bottom. The edges have an 11 degree relief anyway so I didn't think I needed much. (That was my assumption anyway).  Having said that,  I maybe should have a little more on the side. When I rough out the slot with a mill there tends to be jagged chips hanging on the edges. That stuff scratches on the tool on the first pass. It has clearance when it's cutting though. I took pictures showing the bottom and side. I don't know if it will help. It's kind of hard to see.


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## westerner (Dec 19, 2020)

Very nice, Chuck!

You got my wheels turning.
Thanks.


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## 7milesup (Dec 19, 2020)

Took me a few times reading your post on positioning the insert, but made perfect sense after I engaged my brain.

What are the inserts?  Anything special?


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## Chuck K (Dec 19, 2020)

7milesup said:


> Took me a few times reading your post on positioning the insert, but made perfect sense after I engaged my brain.
> 
> What are the inserts?  Anything special?


The only thing special about them is that I had them on hand. I pretty much always use hss for turning so I've never gotten educated on insert nomenclature. They're triangular and they have about 11 degrees of clearance. I don't know what brand they are.  Probably imports.


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## Chuck K (Dec 20, 2020)

Chuck K said:


> The only thing special about them is that I had them on hand. I pretty much always use hss for turning so I've never gotten educated on insert nomenclature. They're triangular and they have about 11 degrees of clearance. I don't know what brand they are.  Probably imports.


I have a lot of misc. Inserts. I had quite a few of the type I used. That's the only reason I used that particular insert. It seems to work.


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## Chuck K (Dec 20, 2020)

Now that I've done some test holders I decided to use a piece of bar and make 6 BXA holders.  I generally make ppl projects out of scrap when I can.  So I found a bar that was the appropriate size on my scrap pallet. 



When I started milling it to square it up it became apparent that it was some kind of cast.  It was either use it or saw a bigger chunk down to size, so I just went with it. 


I cleaned up the four sides and then started cutting my groove. 


With the groove cut I made my first pass on the dovetail. 


While the milling was going on I started making the thumb wheels. I knurled some 1" 1018 bar and then mounted it in my sb 9A. I enjoy using the 9 because it's a machine that I got from a scrap yard. Somehow I get more satisfaction when I use it. Anyway, I needed to part off a bunch of wheels. 


I guess I have hit my limit for pics on this post.  I'll have to continue on another post.


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## Chuck K (Dec 20, 2020)

So I knurled and parted off the wheels. 



I intended to use the soft jaws I made to finish the thumb wheels....until I realized that I don't have that chuck anymore....and they don't fit the bison on the sb.  So as usual I have a project to do so I can finish my project. So I  have 5 big holders for large tools and enough stock to make six regular size holders.


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