Yeah, that's what I'm thinking. I might as well go with stacked baffles instead of mono-core design.
Working with titanium
- Thread starter awptickes
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Yeah, that's what I'm thinking. I might as well go with stacked baffles instead of mono-core design.
This is the lathe I have:
7" x 12" Mini Metal Lathe
7" x 12" Mini Metal Lathe
Ok, Ill post in a bit. Gotta get back to my computer lol.
If you look at another lathe, Id suggest gettin somethin old off CL, or from an auction. You can usually get somethin that can either be cleaned up and work great, or something thats worth more in scrap value and turn a profit lol.
If you look at another lathe, Id suggest gettin somethin old off CL, or from an auction. You can usually get somethin that can either be cleaned up and work great, or something thats worth more in scrap value and turn a profit lol.
Yeah, I needed this one to make the 4130 inserts about a year ago. 
It's proved useful with other things too, but it's at my dad's house so it's hard for me to find time to go use it.
Edit: also, I wish I could find a lathe on CL. Everyone around here knows exactly what a lathe is, and what they've got. No deals to be found on shop equipment.
It's proved useful with other things too, but it's at my dad's house so it's hard for me to find time to go use it.
Edit: also, I wish I could find a lathe on CL. Everyone around here knows exactly what a lathe is, and what they've got. No deals to be found on shop equipment.
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So basically, with that lathe a test indicator wont do much good. You cant dial the live chuck in, so your at the mercy of how well it can repeat a grip. I can assure you, that chuck WILL NOT re-grip bar stock as accurate as you need it too.
(IF you take the "stacked washer" approach)
For what your making, you need accuracy with both bores and diameters and they have to be dead concentric. If I had to make the parts you need, this is how I would do it. First get a mag base travel indicator. A nice one. Mitutoyo, Brown and Sharpe, maybe Starrett, that reads in half thou (0.0005) increments. Practice using it on your cross feed. Also, invest in a parting tool with carbide inserts. You may also need to buy a tool holder to get it to work on your tool post (no gay). Once your good with those, your ready.
(Kinda gunna go off on a tangent here)
Make sure to buy more material then you think you need. Using the stacked washer method will require a lot of excess material. You will need material to accommodate X thickness per washer, parting tool width (prally gunna be up near 0.1) times number of washers, clean up (I use about 0.020 on one side for clean up and about 0.050 on the other side to give myself room to hit my finish dimension), and material to hold while you cut the last washer. I would go no less then 2 inches on grip material. Being as you cant fit your bar through the spindle, this is gunna kill you. Your gunna need a lot of short pieces. I wouldn’t hang much more outa the chuck, then you have in the chuck so now your talkin a pretty low yield from your material. Do you already have the material?
Ok, now to the actual cutting. Since you cant manipulate your chuck your gunna need to make one complete washer per setup. If you pull your bar stock in the middle of the operations, that part is lost. Id start by facing the end of the material to your desired surface finish for the final part. Leave the OD alone for now. Now center drill for your pilot hole. Don’t use a spot drill or any other pre drill shit. Has to be a center drill. Like this…
Make sure that the chamfer doesn’t go any deeper then the thickness of your washer plus parting tool dimension. Otherwise getting the next hole concentric will be a lil tougher. For the hole sizes your lookin for, I don’t think a pilot drill will be necessary. Also, if your making washers, since the drill depth is so shallow, the center drill pilot is usually enough. Now, when it comes to making the bore decide rather you want to get your finished size with a reamer or a boring bar. Using that lathe, Id opt for the reamer. Itll wear out faster then a cemented carbide boring bar, but your less likely to blow the ID because of slop in the machine. With a reamer, you should be able to drill about 0.005 under and up size from there. Drill quality will play a role in far under sized the hole needs to be. Reamer quality will be a big factor in your finish ID too. You get what you pay for. If you notice your diameters startin to grow, you can always grind away the used, dull end of the reamer and get back to fresh flutes. Just make sure to grind a decent chamfer of the new end. Once you get the bore finished, use your travel indicator to turn the OD of your material. Pretty straight forward here. Just mind your surface speed (spindle RPM). From what I know, feed rate isnt as critical with Ti. Next, part the washer off. You can use your travel indicator here too. With the machine off, creep the tool up to your finished face until it leaves a witness mark, zero the indicator. Move over the thickeness of you tool and re-zero. Now move to your finish dimension plus excess and part it off. Now turn it around and clean up the other side and your done.
You might want to invest in a drill sharpening jig for a bench grinder, or a drill sharpener. Get good with usin that too lol. If you want pointers on drill sharpening, let me know. That’s one of my strong points.
IMO, if you get your OD’s all within a few tenths of a thou, your ID’s within a thou or 2 and its all dead concentric you should get what your lookin for.
I dunno how much of this you already know, but you wanted me to post my ramblings, so here they are lol. If you have any questions lemme know.
(IF you take the "stacked washer" approach)
For what your making, you need accuracy with both bores and diameters and they have to be dead concentric. If I had to make the parts you need, this is how I would do it. First get a mag base travel indicator. A nice one. Mitutoyo, Brown and Sharpe, maybe Starrett, that reads in half thou (0.0005) increments. Practice using it on your cross feed. Also, invest in a parting tool with carbide inserts. You may also need to buy a tool holder to get it to work on your tool post (no gay). Once your good with those, your ready.
(Kinda gunna go off on a tangent here)
Make sure to buy more material then you think you need. Using the stacked washer method will require a lot of excess material. You will need material to accommodate X thickness per washer, parting tool width (prally gunna be up near 0.1) times number of washers, clean up (I use about 0.020 on one side for clean up and about 0.050 on the other side to give myself room to hit my finish dimension), and material to hold while you cut the last washer. I would go no less then 2 inches on grip material. Being as you cant fit your bar through the spindle, this is gunna kill you. Your gunna need a lot of short pieces. I wouldn’t hang much more outa the chuck, then you have in the chuck so now your talkin a pretty low yield from your material. Do you already have the material?
Ok, now to the actual cutting. Since you cant manipulate your chuck your gunna need to make one complete washer per setup. If you pull your bar stock in the middle of the operations, that part is lost. Id start by facing the end of the material to your desired surface finish for the final part. Leave the OD alone for now. Now center drill for your pilot hole. Don’t use a spot drill or any other pre drill shit. Has to be a center drill. Like this…
Make sure that the chamfer doesn’t go any deeper then the thickness of your washer plus parting tool dimension. Otherwise getting the next hole concentric will be a lil tougher. For the hole sizes your lookin for, I don’t think a pilot drill will be necessary. Also, if your making washers, since the drill depth is so shallow, the center drill pilot is usually enough. Now, when it comes to making the bore decide rather you want to get your finished size with a reamer or a boring bar. Using that lathe, Id opt for the reamer. Itll wear out faster then a cemented carbide boring bar, but your less likely to blow the ID because of slop in the machine. With a reamer, you should be able to drill about 0.005 under and up size from there. Drill quality will play a role in far under sized the hole needs to be. Reamer quality will be a big factor in your finish ID too. You get what you pay for. If you notice your diameters startin to grow, you can always grind away the used, dull end of the reamer and get back to fresh flutes. Just make sure to grind a decent chamfer of the new end. Once you get the bore finished, use your travel indicator to turn the OD of your material. Pretty straight forward here. Just mind your surface speed (spindle RPM). From what I know, feed rate isnt as critical with Ti. Next, part the washer off. You can use your travel indicator here too. With the machine off, creep the tool up to your finished face until it leaves a witness mark, zero the indicator. Move over the thickeness of you tool and re-zero. Now move to your finish dimension plus excess and part it off. Now turn it around and clean up the other side and your done.
You might want to invest in a drill sharpening jig for a bench grinder, or a drill sharpener. Get good with usin that too lol. If you want pointers on drill sharpening, let me know. That’s one of my strong points.
IMO, if you get your OD’s all within a few tenths of a thou, your ID’s within a thou or 2 and its all dead concentric you should get what your lookin for.
I dunno how much of this you already know, but you wanted me to post my ramblings, so here they are lol. If you have any questions lemme know.
I'm wondering how tight the tolerances on the center bore even need to be. If the holes are .010" oversize to the bore, the lateral tolerance for centering the holes only has to be .005" right? I'm pretty sure the baffles don't have a hole diameter that perfectly matches the bore diameter. There's such a thing as too tight when any variance results in catastrophic failure.
I did some research on it before I made a similar piece that I showed in another thread. The bores need to be very consistent, otherwise you get a condition that I cant really describe in this thread.
You just experienced the problem with a friend. Something was off center, bad quality assurance. Im not sure if that will jog your memory, but I dont wanna say too much lol.
You just experienced the problem with a friend. Something was off center, bad quality assurance. Im not sure if that will jog your memory, but I dont wanna say too much lol.
Negative. An ideal condition for my piece is to have 0.0001 tolerances, but that's not going to happen, so it's best to go on the wide side.
