I'd like to cast a 6 or 7" long aluminum cylinder and then bore it till I have an ID of 2". Instead of buying a boring bar, can I make one? (I'm new to lathes, btw.)
What I was thinking off is securing the workpiece to the compound somehow. Get a piece of socker rod, drill a hole somewhere in the middle for the cutting bit (which I also want to make myself). Then drill another small hole for a set screw and grind one side of the cutting bit flat, so the cutting bit won't move when you tighten the set screw. Then put the bar in the chuck in one end and support it with the tailstock on the other end and start boring.
Would that work fine? If so, what would be a good way to secure the workpiece to the compound? There are no t-slots or holes in the compound and I'd really like to find a way to do it without having to drill in my compound because I don't have a drill press so I can't drill straight holes.
As for the cutting bit, a while back I took a printer apart and got a lot of rods that were inside. I think they're stainless. Would a stainless cutting bit be fine for cutting aluminum? Stainless workhardens easily, right? So it'll probably work harden as I grind it with the grinder which mightb e beneficial?
Anyways, I haven't really thought it through too much yet, because I thought maybe I'm above my head here due to my lack of experience with lathes. If I need something done, I can probably come up with a way to do it, but what keeps me from doing it is because I have no idea if it's safe. I guess what I'm saying is I don't know what I can get away with on a lathe, so I don't do it because you know what they say.. better safe than sorry!
Boring on a lathe
-
davidbraley
- Posts: 29
- Joined: Sun May 29, 2011 6:13 pm
- Location: Fort Collins, Colorado
Re: Boring on a lathe
Hi Wikisi,
Your idea of how you would do this task is totally logical, but I'm curious as to why you're not holding the workpiece in the lathe chuck, and the boring tool in the compounds tool holder? Typically when you bore a hole, the part is spun, and the cutting tool is held still. If you're concerned about the boring bar chattering, that's easily dealt with by fiddling with your feeds and speeds. Even with a long bar.
I don't see any easy way to hold the workpiece to the compound. Not compared to doing this the more traditional way. Stainless would not be good enough for a cutting tool. Even in it's hardened condition. You should be able to find a piece of high speed steel for your cutter. Where are you located? If you're close, I'll post a piece off to you. They're so cheap I'm happy to give you one. You can also walk into any machine shop in your area, explain that you're just getting started and ask for a piece of high speed steel for a lathe cutter. I bet the guys there will give you a bag full of them.
Ebay is a great place to buy cutting tools if you didn't already know that. You can even get nice boring bars there cheap too. Just about anything really for the machine shop.
Here is the traditional way to bore a part in a lathe:
Let us know how it goes. Good luck,
David
Your idea of how you would do this task is totally logical, but I'm curious as to why you're not holding the workpiece in the lathe chuck, and the boring tool in the compounds tool holder? Typically when you bore a hole, the part is spun, and the cutting tool is held still. If you're concerned about the boring bar chattering, that's easily dealt with by fiddling with your feeds and speeds. Even with a long bar.
I don't see any easy way to hold the workpiece to the compound. Not compared to doing this the more traditional way. Stainless would not be good enough for a cutting tool. Even in it's hardened condition. You should be able to find a piece of high speed steel for your cutter. Where are you located? If you're close, I'll post a piece off to you. They're so cheap I'm happy to give you one. You can also walk into any machine shop in your area, explain that you're just getting started and ask for a piece of high speed steel for a lathe cutter. I bet the guys there will give you a bag full of them.
Ebay is a great place to buy cutting tools if you didn't already know that. You can even get nice boring bars there cheap too. Just about anything really for the machine shop.
Here is the traditional way to bore a part in a lathe:
Let us know how it goes. Good luck,
David
-David
I cut it off three times! And it's still too short!
I cut it off three times! And it's still too short!
Re: Boring on a lathe
hi David,
boring bar chatter is exactly why I came up with the idea. I can only hold 1/2" diameter tools in my toolpost. I thought a bar at 1/2" diameter, 7+" long only supported in the toolpost would probably chatter like crazy and produce an out of round hole. But so you think it'll be fine given the right feed and speed.. that's great. Holding the piece in the chuck is soooo much easier, hell that's what the chuck is for
So no stainless bits. Ok, well I have some cheap carbide brazed Harbor Freight cutting bits. Would one of these welded to the end of a piece of socker rod hold up? (I suppose that depends on my welding huh 
)
boring bar chatter is exactly why I came up with the idea. I can only hold 1/2" diameter tools in my toolpost. I thought a bar at 1/2" diameter, 7+" long only supported in the toolpost would probably chatter like crazy and produce an out of round hole. But so you think it'll be fine given the right feed and speed.. that's great. Holding the piece in the chuck is soooo much easier, hell that's what the chuck is for
So no stainless bits. Ok, well I have some cheap carbide brazed Harbor Freight cutting bits. Would one of these welded to the end of a piece of socker rod hold up? (I suppose that depends on my welding huh
)Re: Boring on a lathe
One more thing.... if welding on one of those bits to the end of a bar is fine, would it be ok to weld it on so that when the bar is in the toolpost the bit points to the right? That way I can cut in reverse... cutting AWAY from the chuck so I don't have to worry about running into it.
-
davidbraley
- Posts: 29
- Joined: Sun May 29, 2011 6:13 pm
- Location: Fort Collins, Colorado
Re: Boring on a lathe
1/2" is a little small for a 7" deep hole, but totally doable with care and patience.
You can weld your tool to the end of your bar anyway you want. Just make sure the rotation is correct for the cut. I know you understand that.
Carbide is a perfect tool to use, but I doubt you have any way to sharpen it. High speed steel is super easy to sharpen with a limited tool set. You can rough it out on a regular pedestal grinder and finish the edge with a wet stone. For a bar hanging out that far, you will need a tool that is scalpel sharp. Carbide can only be sharpened to that degree with a diamond wheel.
You might consider making a tool holder for the boring bar that bolts directly to the compound. I have made bars for long reach jobs that don't fit into the tool post holder, but instead bolt to the compound where the tool holder does. I hope that made sense. That way I can make my bars as large in diameter as possible. You mention your hole will be about 2" in diameter. That means you could make a pretty beefy boring bar for the job. A 1" bar would be much easier to use. Then your tool wouldn't need to be as sharp. Correctly sharpening tools is a whole other subject.....
What's most important is that you try stuff. You can't get any good at being a machinist without making mistakes. You will learn so much and get a feel for it as you go. I tell my friends that being a machinist is not a spectators sport. Just remember to keep your hands out of harms way, and safety glasses on, and you're good to go! Oh, keeping your mouth shut helps too. Hot chips in the mouth are not fun.
Take care,
David
You can weld your tool to the end of your bar anyway you want. Just make sure the rotation is correct for the cut. I know you understand that.
Carbide is a perfect tool to use, but I doubt you have any way to sharpen it. High speed steel is super easy to sharpen with a limited tool set. You can rough it out on a regular pedestal grinder and finish the edge with a wet stone. For a bar hanging out that far, you will need a tool that is scalpel sharp. Carbide can only be sharpened to that degree with a diamond wheel.
You might consider making a tool holder for the boring bar that bolts directly to the compound. I have made bars for long reach jobs that don't fit into the tool post holder, but instead bolt to the compound where the tool holder does. I hope that made sense. That way I can make my bars as large in diameter as possible. You mention your hole will be about 2" in diameter. That means you could make a pretty beefy boring bar for the job. A 1" bar would be much easier to use. Then your tool wouldn't need to be as sharp. Correctly sharpening tools is a whole other subject.....
What's most important is that you try stuff. You can't get any good at being a machinist without making mistakes. You will learn so much and get a feel for it as you go. I tell my friends that being a machinist is not a spectators sport. Just remember to keep your hands out of harms way, and safety glasses on, and you're good to go! Oh, keeping your mouth shut helps too. Hot chips in the mouth are not fun.
Take care,
David
-David
I cut it off three times! And it's still too short!
I cut it off three times! And it's still too short!
Re: Boring on a lathe
IF YOU DO THIS THE WORK CAN BE PULLED OUT OF THE CHUCK!!!!!!cutting AWAY from the chuck so I don't have to worry about running into it.
BE CAREFULL !
If you have problems seing where the chuck is make up a stop so the tool will stop before hitting it. A simple clamp on the bed will work.
When you say weld the Carbide tip, I hope you mean braze / silver solder? I dont think you can Arc weld it.
If you have a stady rest I would try and use that to help hold the work.
Down the neck of your shirt an't eatherHot chips in the mouth are not fun.
Most of all , Have fun and keep safe
I like to build "Stuff" using Stuff that costs Stuff All!
Re: Boring on a lathe
Well, I found a 5/8" steel hexagon shaped stake that fits in my toolpost like a glove. Just weld a cutting bit to it and voila.. a boring bar
Yeah, that makes sense. I hadn't thought of that. I'm sure it'll come in handy in the future. Thanks for that!davidbraley wrote:You might consider making a tool holder for the boring bar that bolts directly to the compound. I have made bars for long reach jobs that don't fit into the tool post holder, but instead bolt to the compound where the tool holder does. I hope that made sense.
Re: Boring on a lathe
Good to see a solution for the problem 
I like to build "Stuff" using Stuff that costs Stuff All!