Making a solid brass flange on lathe

[brino]

More like a facing cut, but kinda a plunge facing cut.... if I am fully understanding the geometry of your work.

It could be the same turning tool if you turn the tool holder, but you do need side clearances.

Brian

 

[DaveInBucks]

That brings the first question, what tool post are you using?



Dead sharp tool, no top rake, no chip breakers...



How tight does the fit have to be? If it needs to be a precise fit, then measuring that might turn out more challenging than making it...



You certainly could get such a drill bit, but it's going to be more than your lathe wants. And probably tear up the morse taper in the tailstock..... You want to bore that.



You must (within reason, there are ways.... but within reason....) you must drill a hole large enough to let your boring bar enter.
This will leave the "point" of the drill at the bottom of that hole. You can drill the hole to depth "plus the drill point", and after you bore the hole, it'll be flat on the bottom, except that "dimple" in the middle from the drill point.
OR, you can drill the hole to put the drill point exactly at the bottom of the finished hole. You'd then bore the hole, and it will be shallow, but at that point, once it's widened, 98 percent of boring bar options out there will let you "face" the bottom of the hole, bringing the whole thing to depth with no divots in the bottom.

But that's about all we can can give on the boring bar at this point. We've got to know how you're holding it to the lathe before we can give you any solid advice on "which" tool to buy.

Truth be told... At a quarter inch deep- You could grind a boring tool out of a 3/8 HSS blank and plow through that. With a little restraint, you could do it with quarter inch HSS, so another pertinent question might be "Are you getting a job done", or "Is this the job that is a trigger for filling out an incomplete tool collection? Both answers are valid, and warrant very different advice.

Very helpful…I’ve got the Aloris AXA tool holders and none of this needs to be super precise. I did see it as an excuse to learn boring methods and buy another piece of kit. But seems for this I’m wonder if one of the 3/8th HSS tools from my grizzly set will do the job. I guess i face it first…then drill it largest size enough to get the tool in there. Then take small cuts until I get to 1.25 and my parts fit.

 

[mmcmdl]

Welcome aboard H-M Dave . Not far away and always enjoy the Tractor Pulls .

 

[pavyan]

Also, brass can grab your drill bit, it’s best to be ready for it. Some will grind their drill bits to have less cutting ability.
I always drill as much as you can then bore to spec.

​

@DaveInBucks, if you were to drill into this brass (any brass ):

As Janderso very correctly pointed out, brass can be "dangerous" to drill (especially when you ENLARGE an existing hole with a larger drill bit).
To tell you the truth, at the beginning of my workshop "career" I had a few such accidents

Drill bits specifically designed for brass (and bronze) have a smaller helix angle - yes, you can use regular drills for steel, but you have to make a slight correction to the cutting edge: namely make a zero rake angle.

I can't describe it myself, because I don't know the language well - and the nomenclature for the elements of the drill bit is very different in Polish and English; however, I found a page where it is explained: https://handycrowd.medium.com/drilling-brass-the-easy-and-safe-way-f1494d449d3a

I "blunt" the drill bits in this way on a bench grinder - with a diamond wheel - but it can also be done as described above: with honing stone (or diamond file).

Special drill bit for brass:

 

[Janderso]

​

@DaveInBucks, if you were to drill into this brass (any brass ):

As Janderso very correctly pointed out, brass can be "dangerous" to drill (especially when you ENLARGE an existing hole with a larger drill bit).
To tell you the truth, at the beginning of my workshop "career" I had a few such accidents

Drill bits specifically designed for brass (and bronze) have a smaller helix angle - yes, you can use regular drills for steel, but you have to make a slight correction to the cutting edge: namely make a zero rake angle.

I can't describe it myself, because I don't know the language well - and the nomenclature for the elements of the drill bit is very different in Polish and English; however, I found a page where it is explained: https://handycrowd.medium.com/drilling-brass-the-easy-and-safe-way-f1494d449d3a

I "blunt" the drill bits in this way on a bench grinder - with a diamond wheel - but it can also be done as described above: with honing stone (or diamond file).

Special drill bit for brass:

View attachment 510998

I have a couple of those style bits I didn't know they were for brass!!

 

[pavyan]

As they say, a human learns throughout your whole life* - and I'm sure I'll learn something too, from you all

*And dies a stupid anyway (that's what they say, too )

 

[Jim F]

Very helpful…I’ve got the Aloris AXA tool holders and none of this needs to be super precise. I did see it as an excuse to learn boring methods and buy another piece of kit. But seems for this I’m wonder if one of the 3/8th HSS tools from my grizzly set will do the job. I guess i face it first…then drill it largest size enough to get the tool in there. Then take small cuts until I get to 1.25 and my parts fit.

If you want to take a day trip to Williamsport, I can hook you up with HSS bits, in any size you need.

 

[markba633csi]

With a HSS bit I would just face back and forth until I have created a hole, then move the carriage in and out to even up the sides of the hole.
You can also use the compound to do that instead of the carriage, if you set it parallel to the ways- easier to control
You need a bit with a somewhat sharp pointed nose to give your hole a tight corner- a bench grinder is invaluable here
Naturally you want to make sure your hole ends up the correct diameter, so you have to keep checking with your caliper

 

[Jake M]

Very helpful…I’ve got the Aloris AXA tool holders and none of this needs to be super precise. I did see it as an excuse to learn boring methods and buy another piece of kit. But seems for this I’m wonder if one of the 3/8th HSS tools from my grizzly set will do the job. I guess i face it first…then drill it largest size enough to get the tool in there. Then take small cuts until I get to 1.25 and my parts fit.

Cool. The tool post will make it easier to get a tool in there without needing a separate holder. Using existing tool "as is" to bore a hole that small is a problem, because you're on center, inside of a circle, which means everything below the cutting edge has to be ground away.

You might could modify an existing tool if you're lucky, but depending on the tool, that could be problematic too. What's your Grizzly set? I looked quick and only saw a 5/16 kit? The right handed cutter could be a candidate, but that's probably the most used one in the set, and it's NEVER gonna do that job again..... It doesn't really lend it's self due to the huge chip breaker in it. (That is in effect a HUGE positive rake angle, that's not gonna go well, it'd have to be ground right off before you started making a boring tool. the lower edge/corner below that would have to be rounded to make clearance so it doesn't contact the "hole" before the cutter does.

I'd bet you could make a nice one out of the back end of one of those tools...

Here's a general tip for owning a lathe. It applies here, but it applies to a LOT of situations you'll bump into starting off... When you're ordering "something" from "somewhere", throw in a couple of sticks of high speed steel in your favorite size. Then when you run into something new, you're always prepared, and can get a job done while you decide on "will I ever do this again", is there a better engineered solution, all that stuff. It really keeps projects moving and lets you take the time later to sort out the future.

 

[rwm]

One thing about brass that I don't think was mentioned here: Do NOT start with a small drill and work your way up. Brass will grab the drill. Start with a small spotting drill, and then move to the largest drill you intend to use. That will prevent the grabbing.
If you don't have a boring bar, you could use an end mill held in the same fashion. I may not give a perfect surface finish but should work.