# Boring Head?



## DaddyHeath (Mar 9, 2022)

Hey all!
To preface, I have a Micro Mark Sieg mini lathe and a 1HP Series 1 J Head Bridgeport.
Also have rotary table, dividing head, and enough end mills to choke a boar (plus the requisite 60 degree dovetail end mill)
Currently torn between dropping some coinage on a quality boring head or attempting to make one.

My questions then lean towards what alloy steel would be best for the body and slide, what screw size and thread should be used for the adjustment, and what would be the largest size I could use reliably on my milling machine?


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## ttabbal (Mar 9, 2022)

I use a Criterion DBL-202. It does a great job and I don't think it's made with anything particularly special. A BP should be able to run some good size boring heads, but really how big do you want to make holes? Most of them have a horizontal hole to hold tools for big bores. 

I recently finished a boring/facing head project. This one is made from cast iron body castings and is quite a bit larger and heavier than the Criterion. http://mlatoolbox.com/MLA-7.html 

It's a fun project, has good instructions and drawings, and considering the cost of other facing heads, it's a deal.  

As an interesting aside, you don't need a big boring head to do big work. Though I wouldn't really recommend it, this worked well for me. 









						Large work on a Bridgeport
					

I got a spacer for it. It fits great on the column, but the turret is a few thou too big. I was thinking of clamping it to the table and boring it out a little. I figured I should ask here in case I might have missed something and to get tips for the setup. I tried lining it up with the long...




					www.hobby-machinist.com


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## Winegrower (Mar 9, 2022)

DaddyHeath said:


> Currently torn between dropping some coinage on a quality boring head or attempting to make one.



I've been plenty happy with the relatively inexpensive (<$100) kits for 2" or 3" bars.   I have both, if I'd known better I think the 3" would have been enough by itself.


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## NCjeeper (Mar 9, 2022)

I bought a 2" with an R8 adapter from Shars a few years ago. Works just fine.


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## mikey (Mar 9, 2022)

DaddyHeath said:


> ... and what would be the largest size I could use reliably on my milling machine?


Practically speaking, the biggest I would go would be a 3" head. It's big, relatively speaking. 

Rather than make one, I would buy this one. For a Criterion DBL-203 that has seen very little use, that guy is giving it away. Clean it up and it will work fine. All the important screws are there. It is missing two of the three screws that hold the boring bars in but they are simple to find and replace. Otherwise the head is in really nice condition. 

Making a head is not a big deal for an experienced hobby guy but I would use at least medium carbon steel for the body and bar holder, maybe 1144, and you will need to be pretty good at screw cutting. My personal opinion is to buy this kind of tool if a high quality one is available at a fair price, like the one I linked to above. Build the tool when the one you need doesn't exist.


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## DaddyHeath (Mar 9, 2022)

mikey said:


> Practically speaking, the biggest I would go would be a 3" head. It's big, relatively speaking.
> 
> Rather than make one, I would buy this one. For a Criterion DBL-203 that has seen very little use, that guy is giving it away. Clean it up and it will work fine. All the important screws are there. It is missing two of the three screws that hold the boring bars in but they are simple to find and replace. Otherwise the head is in really nice condition.
> 
> Making a head is not a big deal for an experienced hobby guy but I would use at least medium carbon steel for the body and bar holder, maybe 1144, and you will need to be pretty good at screw cutting. My personal opinion is to buy this kind of tool if a high quality one is available at a fair price, like the one I linked to above. Build the tool when the one you need doesn't exist.


Well that's a winning deal right there!  I'll have to turn the shaft down just a tad, but that's no big issue.  Wonder if it's integral or removable.
Guess I'll find out when it arrives!


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## mikey (Mar 9, 2022)

All DBL heads have a 7/8-20 mount so you can buy or make an adapter to suit your needs. Yes, an R8 adapter is readily available.


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## Badabinski (Mar 9, 2022)

I have a Wohlhaupter UPA2 that I absolutely adore, although I paid dearly for it. I really prefer boring heads that use a large ring rather than a screw which requires an Allen key, and being able to do facing ops in the mill is just awesome.

The Criterion boring head recommended above will absolutely serve you well, however.


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## mikey (Mar 9, 2022)

Who wouldn't prefer a UPA2? I am green ...


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## mikey (Mar 9, 2022)

DaddyHeath, I forgot to mention that the best bars to use with these heads are cobalt HSS. They will cut really well at much lower speeds than carbide, either brazed or inserted. The DBL-303 uses 3/4" shank bars that are unfortunately more expensive. 

High quality cobalt bars are hard to find nowadays. Sit down when you look but this is the set I would suggest. Used properly, they are the last set of bars you will need to buy. They are M42, so 8% cobalt, and they have a 5 degree lead angle at the tip so they will cut really well with lower cutting forces, which means less potential for chatter in the bore. At the right speed and feed, the finish a cobalt bar leaves in the bore looks like a mirror.


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## ericc (Mar 9, 2022)

I tried making one out of 4140 as-forged the "right" way.  Somehow, it didn't work out well.  The endmill just stopped cutting.  Then, the TechShop went out of business.  I'm lucky I didn't end up holding the bag on any loans, memberships or lost items.  I hid the partially done boring head, and am ashamed everytime I see it.  During Covid times, we are encouraged not to needlessly beat ourselves up about perceived failures.  Anyway, I saw this cool post on homemadetools of one made out of barstock.  When I really needed one (for a single hole), I made it out of junk cast iron and used an orphan 3/8" shank no-name brazed carbide tool.  That thing worked great, and I used it one more time, again with excellent results, but this time with a right hand tool for turning a stub on a lifting eye that was too unwieldy to chuck in the lathe.  I just run it slow and take my time, and it hasn't blown up yet.  Actually, all the parts in serious tension were made out of carbon steel barstock.


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## DaddyHeath (Mar 9, 2022)

Badabinski said:


> I have a Wohlhaupter UPA2 that I absolutely adore, although I paid dearly for it. I really prefer boring heads that use a large ring rather than a screw which requires an Allen key, and being able to do facing ops in the mill is just awesome.
> 
> The Criterion boring head recommended above will absolutely serve you well, however.


Holy hell, that UPA2 looks like an absolute beast!


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## jwmelvin (Mar 9, 2022)

mikey said:


> The DBL-303 uses 3/4" shank bars that are unfortunately more expensive.



[mention]mikey [/mention] is it horrible to sleeve a shank in a boring head as one might do when boring on a lathe? I could see how the single set screw in a boring head might struggle to provide the clamping force and rigidity that one wants. But it seems possible. 

Or if one wanted, I could see silver brazing a sleeve on a smaller-shank tool to fit the 3/4” boring head. 

Not ideal perhaps but the expense can be a bit much at times.


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## mikey (Mar 9, 2022)

jwmelvin said:


> [mention]mikey [/mention] is it horrible to sleeve a shank in a boring head as one might do when boring on a lathe? I could see how the single set screw in a boring head might struggle to provide the clamping force and rigidity that one wants. But it seems possible.
> 
> Or if one wanted, I could see silver brazing a sleeve on a smaller-shank tool to fit the 3/4” boring head.
> 
> Not ideal perhaps but the expense can be a bit much at times.


Yes, you can, and that is a very good option, Jason. I'm ashamed not to have thought of that. Smaller bars are a lot cheaper.


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## ddickey (Mar 9, 2022)

This one looks awesome.




And the Wally


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## DaddyHeath (Mar 10, 2022)

Just wanted to say thank you, this was my first post and y'all helped tremendously!


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## John O (Mar 10, 2022)

One I made to fit 1/4" bar in 3/4"


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## DaddyHeath (Mar 13, 2022)

mikey said:


> All DBL heads have a 7/8-20 mount so you can buy or make an adapter to suit your needs. Yes, an R8 adapter is readily available.


Fun fact: not all DBL boring heads have a 7/8” mount  ya live and learn!


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## jwmelvin (Mar 13, 2022)

DaddyHeath said:


> Fun fact: not all DBL boring heads have a 7/8” mount ya live and learn!



What size are your threads?


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## DaddyHeath (Mar 13, 2022)

jwmelvin said:


> What size are your threads?


1 1/2 - 18 
Just turned the shank down to 3/4 as that’s my largest R-8 collet


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## mikey (Mar 14, 2022)

Well, all DBL heads in the 200 series have 7/8-20 threads. At least I got the threaded part right!


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## DaddyHeath (Mar 14, 2022)

mikey said:


> Well, all DBL heads in the 200 series have 7/8-20 threads. At least I got the threaded part right!


But this is a DBL-203…


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## mikey (Mar 14, 2022)

I'll eventually get it right. All the 202 heads have a 7/8-20 thread. All the rest of them don't matter so I don't care what their thread is.


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## DaddyHeath (Mar 14, 2022)

mikey said:


> I'll eventually get it right. All the 202 heads have a 7/8-20 thread. All the rest of them don't matter so I don't care what their thread is.


There we go!  Accuracy is only important in the act of machining, not the discussion of it


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