anyone be interested in making a video of lathe work?

[Hydro Junkie]

im trying to talk dad into getting me a combo mill/lathe for xmas, but i highly doubt that is going to happen. A bench top unit might be much more reasonable.

I've never used the combo units, but those I've talked to that have normally move to the dedicated mills and lathes. The problem with the combo unit is threefold:

1) You are always having to work around the powerhead you're not using at the time. This makes using your measuring tools much more difficult and setting up equally so.

2) You are much more limited on project size, especially when milling. Whatever you are milling is limited to the cross slide's limits which, instead of being limited by the table size itself, is limited by the lathe's head and tailstock locations. For example, if your combo is 12" between centers, you might be able to mill something 3 to 4" long and maybe 2" or so wide. I can go bigger than that with my little Sherline mini-mill.

3) You will, in many cases, have to buy different tooling anyway for the two different operations. If you're going to have to spend the money on tooling anyway, why not just buy a dedicated lathe and mill to begin with? Nothing wrong with the benchtop types as long as the bench is rigid enough to support the tool without vibrating.

One other thing you need to consider is the taper of the tailstock and powerhead. In my case, I need both #0 and #1 Morse tapers on my lathe and a #1 Morse on my mill. Others units can use "R" tapers, different sizes of Morse tapers, and who know what all else. Just something else to consider

 

[Tom Foley]

With the plug pilot hole done and all bottom side operations complete , would a tiny lack of concentricity by flipping the part really be that big of a deal for this part ? It would not seem so to me as all the critical operations beside head screw holes( mill or drill press ) are done from the bottom side .

 

[glenng]

It's gets under my hide when most all of these machining topics go sideways and we get scolded buy machinists that have equipment that took a lifetime to aquire. Lets be REASONABLE, Please!

Yes, many of us know that a collet is the best way to hold these parts, but those collet holding fixtures are usually made for much larger equipment.

Rant over.

O.K., Sorry I put in my 2 cents on how to do it right. I have a 13"X48" south bend lathe I paid $ 700.00 bucks for and it will take the 5c colletts. Emergency(soft faced ) collets are about $15.00 ea. I will not offer advice on this again.

Glenn

 

[RodneyPierce]

Glenn, please done feel like you have to refrain from commenting. Jerry just knows alot of people like myself are on a limited budget is all. Im liking where this is starting to head now. Getting some good information. I found a very helpful site with many reviews and such. www.mini-lathe.com

 

[Jerry Wyss]

This certainly would be okay if the piece is finished without moving the holder. What happens if you want to re-machine the piece after the holder has been moved? As a side note the holder could be zeroed in a four jaw chuch at any time. It would be better if the solid hardened holder was inserted in the taper of the lathe spindle. Further accuracy can be obtained by marking the holder to insure that it is inserted in the same position & then regrind the seat that 5-C collet sets in. Your idea is fine because you understand what the process is with the tools you have on hand!

Thanks for that Jim,, I was wondering if the special collet holder could be trued in the 4 jaw, would it still be true if you took it off and put it back on again. Is the centering ability that good with just changing the heads? Really it appears to be the case because I have both heads and have used both before. In other words, just have the 4 jaw ready to go with special collet holder when needed.

 

[RodneyPierce]

Guys, if you check the runout on the head, and make sure its square before you start cutting, I guess i dont understand why the standard 3 jaw wouldnt work? Or is it just a case of not having to fiddle around, and spend the extra time when using the collet?

 

[Jerry Wyss]

With the plug pilot hole done and all bottom side operations complete , would a tiny lack of concentricity by flipping the part really be that big of a deal for this part ? It would not seem so to me as all the critical operations beside head screw holes( mill or drill press ) are done from the bottom side .

In my experience the loss of the concentricity of the plug tower causes bad fit with water and aircooled heads,, turns the thing into a ham job. The biggest problems are with the "run-out" I believe its called on the squish face and the part that seats on the sleeve flange. If things get off there its almost impossibe to correct and it makes the button useless.

 

[topfuel443]

Guys, if you check the runout on the head, and make sure its square before you start cutting, I guess i dont understand why the standard 3 jaw wouldnt work? Or is it just a case of not having to fiddle around, and spend the extra time when using the collet?

Dial indicator and a 3 jaw has worked fine for me for many head buttons.

~ James

 

[Jerry Wyss]

[quote name='glenng' date='14 September 2010 - 05:55 PM' timestamp='1284512101'

O.K., Sorry I put in my 2 cents on how to do it right. I have a 13"X48" south bend lathe I paid $ 700.00 bucks for and it will take the 5c colletts. Emergency(soft faced ) collets are about $15.00 ea. I will not offer advice on this again.

Glenn

My apologies Glenn, I was bracing for a bashing from another machinist,, been there, done that before.

 

[Jerry Wyss]

Guys, if you check the runout on the head, and make sure its square before you start cutting, I guess i dont understand why the standard 3 jaw wouldnt work? Or is it just a case of not having to fiddle around, and spend the extra time when using the collet?

The jaws on the heads of the samller lathes can get ahold of that very precious area that goes into the sleeve very well. I have ruined a button when I was first used a,

how do I say it, I ground a 3/16ths tool bit to remove material on the inside of the hemispherical button bubble. It was ground similar to an ice cream scoop, a very sharp ice cream scoop. I leaned on the feed just slightly to too much and ripped that button right out of the jaws. That was perdy much the end of all my previous work on that button,, in other words, 3 hours for nuthin'

 

[Sean Bowf]

I am def no expert, but I have milled a few head buttons on a three jaw. I do agree that it is nearly impossible to remove a piece from my lathe, then put it back in and have it perfectly true to where it was.

But...little trick I use (probably learned it here), is to use something similar to a piston stop. Chuck that in the lathe. I made a spacer or two to move the button further out from the button holder... Then I can just unscrew the button and flip it over, and screw it back on.

Sean

 

[Sean Bowf]

Here is a pic with a button plank next to it.

Sean

 

[Jerry Wyss]

Many of you could benefit from a company called "emachineshop.com". If they're still in the buisiness they will let you download their 3-D design program. I designed up a blank that could be finished for about 3 differnt 21 engines. It saved a lot of time over turning them from 1-1/2" round stock. Its a little difficult to get the knack of the design program but you design in 2-D first, side , top and bottom. The side view is drawn with the 3 rectangular sections then the top and bottom are drawn as round sections. Give all sections a thickness and width. Once all the program areas are satisfied you can hit the 3-D button and view your part. You can rotate the button in any direction and any color or finish.

You then choose the type of equipment to make your part,(really, its their decision there), level of finish, type of material and quantity of parts.

I had them make me up a 15 @ $13 each several years ago. They're mostly in Thunder Tigers all over the planet.

Sorry about the pic and PVC glue on my fingers,, seems like the camera focused on my hand.