making a pulley on a lathe

[Torch]

Why use a mandrel?

4" chuck to make a 6" pulley.

[warmstrong1955]

Why use a mandrel?

4" chuck to make a 6" pulley.

That's what I understood....not enough chuck.....

Bill

[GlennW]

Well, that answers that!

Didn't catch that part.

[Dan]

I mean this. I am mightily impressed with how kind and patient you folks have been. I mod on a MB forum and would give my left, small finger to get folks to be this nice and informative to new people. (99.9% are but just seems to always be some being less then kind)

LOL, story of my life. A dollar short, a day late and too small a lathe chuck.

I thought I was much closer tool wise. (really frustrating ) Not really a big deal. just frustrating. Ran out of money weeks ago, snork.

Given your input, this is plan Q. Make key way and center hole on a drill press using this http://www.grizzly.com/products/5-1-2-x ... able/H7979 and an oversize blank for the pulley. (so can be trimmed down for concentricity) Use keyed shaft as a mandrel and tapping it to accept a set screw with a washer. Bummer. No way to lock my drill press from rotating.


On to plan Q1 get this so as to be able to adjust height to cut the key way. http://www.harborfreight.com/quick-chan ... 42806.html

Little Machine shop very kindly answered my question in less then a day and said this face plate would fit my machine.
http://littlemachineshop.com/3400 Using an oversize blank, I think this will work. As far as centering?

This really is a blast. Gonna be even more fun if I ever actually start cutting parts!

[warmstrong1955]

Ummmmm..... OK..... but if you're going to purchase a face plate.... turning on an arbor is a method you no longer need, and Glenn's approach is the way to go.

If you use some stock, that is too thick, and oversize in diameter, you can drill 3, or 4 holes in it to mount it to the face plate. Center it with a DTI. Then do what Glenn said in his post. You don't need an arbor. Wam-bam....when you're done on the lathe, all you need to do is broach a key-way.

How are you planning on broaching?

Bill

[Torch]

(I see Warmstrong jumped in whilst I was distracted by grandkid #5. He makes some similar points but I'm not going to edit my comments now)

I mean this. I am mightily impressed with how kind and patient you folks have been.

It is that kind of place. Speaking personally, my motivation is to "pay it forward" in return for all the assistance I have received from guys like Harold and Glenn -- especially when I was just starting out.

I thought I was much closer tool wise. (really frustrating ) Not really a big deal. just frustrating. Ran out of money weeks ago, snork.

Get used to that feeling...

Given your input, this is plan Q. Make key way and center hole on a drill press using this http://www.grizzly.com/products/5-1-2-x ... able/H7979 and an oversize blank for the pulley. (so can be trimmed down for concentricity) Use keyed shaft as a mandrel and tapping it to accept a set screw with a washer. Bummer. No way to lock my drill press from rotating.

A compound slide table is not absolutely necessary, although it is handy. If you layout the centre and centre punch the material, you can set the tip of a centre drill in the dimple fairly accurately. Start drilling the hole, then stop the press. Lock the quill down to keep things centered and clamp the work to the table while you finish drilling the hole.

Little Machine shop very kindly answered my question in less then a day and said this face plate would fit my machine.
http://littlemachineshop.com/3400 Using an oversize blank, I think this will work. As far as centering?

Personally, I find a faceplate is most suitable for thin, flexible items like refacing a motorcycle disk. The work must be bolted to the faceplate somehow, centred, etc. Certainly useful at times, but I think I'd rate a nice 6" 4-jaw chuck as more versatile -- albiet more money.

That said, mounting the piece -- to a faceplate or a chuck -- will allow you to bore the centre hole, which can be more accurately sized than drilling. I say "can be" knowing full well that Harold will be choking when he reads that, but he's had lots of practice and will always be more accurate boring. Until you've had some practice and obtained some accurate inside measuring tools, you will not be, so practice boring some scrap a few times first. By "scrap", I mean similar material, since different materials respond differently to a given rake, relief, etc.

On to plan Q1 get this so as to be able to adjust height to cut the key way. http://www.harborfreight.com/quick-chan ... 42806.html

A QCTP is really nice (and not just for cutting a keyway). But not absolutely necessary if money is tight. If you are planning to cut the keyway into the pulley using the toolpost method, you cannot use a mandrel to secure the work. You will have to have it mounted to a faceplate or in the chuck. (Otherwise, there is no hole...) If you want to use a mandrel with a key, you will have to broach the hole, using one of those bushings noted earlier in this thread, the appropriate width of broach and a press. BTW: a typical Chinese 1-ton arbour press is plenty powerful enough, but too darn short for broaching. Don't Ask Me How I Know This (tm). And yes, you can tap the broach with a hammer to start it in far enough to get it under the arbour press, but the broach is very hard and very brittle and can shatter into a million pieces if struck just a hair off-centre. Again, DAMHIKT(tm).

Cutting the keyway on the mandrel can be done with a tiny endmill. Gently. Very Gently. And make sure things are very well secured. DAMHIKT(tm)

[Dan]

Dang, any post that begins with "Ummm" pretty much means I missed a whole lot, Warmstrong, lol.

What I was thinking (this time, Q2 plan) Was that centering on a face plate would be near impossible. I do own one of these; http://littlemachineshop.com/products/p ... &category=
How could the work piece be clamped so as I could center it efficiently?

now thinking I would drill the center hole. Then make the key way with this; http://www.harborfreight.com/quick-chan ... 42806.html (so as to be able to adjust for height) using the boring bar/cutter from this kit. http://www.harborfreight.com/30-piece-m ... -3448.html

Just got a 25% off coupon...

I don't really want to buy that kit but want that particular boring bar. Suggestions greatly appreciated!

Torch, very cool on many levels and thank you.


Would it be advisable to just buy a 6" 4 jaw chuck and QCTP? (Quick Change tool post)((Had to look that up) fiscally and production efficient?

If it is any conciliation, I spend hrs every day reading and rereading your folks suggestions and hold them in high regard. Just takes me a while to catch on.

..and I am "Lean manufacturing" certified. School thing. We played with Legos and made toast in very efficient manor.

If you ever have trouble making toast or small Lego houses in groups of 6 or more, I can help.

(Trig & algebra, not so much but I aced toast and legos)

[Torch]

What I was thinking (this time, Q2 plan) Was that centering on a face plate would be near impossible. I do own one of these; http://littlemachineshop.com/products/p ... &category=
How could the work piece be clamped so as I could center it efficiently?

That's for use on a milling machine. What you want is a Dial Test Indicator (DTI) and a magnetic base. You clamp the work lightly to the base plate -- just tight enough to resist gravity -- then find the high spot with the DTI. Tap gently with a brass-, dead blow-, or wood- hammer to gently shift it to centre and re-check. Repeat until satisfied and tighten it down. Here's a nice Japanese made Mitutoyo DTI for a decent price: http://www.ebay.com/itm/281177635582. EDIT: here's the same one with a base: http://www.ebay.com/itm/Special-Magneti ... 0794333539?

using the boring bar/cutter from this kit. http://www.harborfreight.com/30-piece-m ... -3448.html

Cutting a keyway with the toolpost is probably the only thing that boring bar is useful for. Provided you need a 1/8" keyway. I have one of those (bought it separately for around $5, so there's no need to buy the whole kit) and have found it to be frustrating. For boring, I have better luck with the ubiquitous brazed-carbide boring bar sets, which I re-grind to a keener angle and increase the relief (more like a HSS profile). However, if you use that for cutting a keyway, minimize the stick-out and take shallow cuts because it won't take much to snap a 1/8" cutting tool forcing it in that way, even in aluminium.

Long-term, if you are going to be making keyways on a regular basis, I'd invest in the broach and press. If it will be an occasional exercise requiring keys of widths other than 1/8", then grind a 1/4" bit, mount it in your tool post (or QCTP holder) oriented like a facing tool on just enough of an angle to clear the bore allowing you to push as nearly straight-in as possible.

Would it be advisable to just buy a 6" 4 jaw chuck and QCTP? (Quick Change tool post)((Had to look that up) fiscally and production efficient?

Some guys hate a 4-jaw chuck, because they are fiddly. Unlike a 3-jaw scroll chuck, each jaw is independently adjusted and you have to use a DTI to centre anything. But a 4-jaw is more versatile than a scroll chuck for exactly that reason. You can grip irregular or out-of-round stock. You can deliberately off-set the work to turn ellipses or lobes or drill off-set holes. And you can reverse 1 or more of the jaws for unusual applications. The trick to quickly centering a 4-jaw is to buy an extra chuck key, and work 2 jaws simultaneously. Loosely clamp the work, find the high spot across 2 opposing jaws with your DTI and tighten the high jaw while simultaneously loosening the opposite one with the second key. Rotate 90° and repeat. Recheck on both sets to fine-tune. Tighten opposing jaws simultaneously and evenly so nothing shifts and you're done. Bear in mind that you may need an adapter plate to fit the 4-jaw to your machine.

As for the QCTP, I have the somewhat more traditional "B" series wedge style and I love it. Swapping /adjusting tools is fast, easy and repeatable. I have no experience with that one from Harbor Fright. The design may be perfectly "repeatable" -- ie: tool ends up back in exactly the same place each time -- and it may fit your machine. Or not. I'd research that design and dimensions very carefully before plunking down any cash. Some stuff from HF is Ok, but much is built down to a price point.

[warmstrong1955]

I'm going to try a different approach, since you seem open to buying more toys.

First, I'd get a 6" three jaw chuck. That would be the easiest way to hold your material.

Build the pulley just as Glenn described.
Not sure what you have for boring bars & tools/tool holders. If you don't have what you need, do some looking at Enco. Personally, I'd avoid Horror Freight for that kind of stuff. Purchasing a quick change tool post is not a bad idea, but it's not what I would do to cut a keyway.

Buy a broach, and a bushing, and an arbor press. Keyways can be cut with lathe, and a drill press or mill, with a properly ground tool, but it's slow. You'll also have to devise a method to lock the spindle from rotating.
Broaches are fast, and clean. The 3/8" x 3-1/4" long keyways in the pics, 1018 steel, took me about 45 minutes to cut all four on my hydraulic press. Shorter and smaller ones are a lot faster. My press didn't have enough stroke in the ram, and I had to add & remove spacers to make the full cut.

http://www.dumont.com/resource-center/s ... -broaches/
http://www.use-enco.com/CGI/INSRIT?PART ... A=325-5640
http://www.use-enco.com/CGI/INSRIT?PART ... A=395-2116

Want to save a buck? Enco has import broaches, but I can't vouch for their quality. I can for duMont broaches, which is all I own. Good stuff.
http://www.use-enco.com/CGI/INSRIT?PART ... A=395-1112

Broach Data. I highlighted what you probably need in blue. Check the specs, and make sure it's what you need.

Broach Data.xls

(168 KiB) Downloaded 328 times

Questions?

Bill

[Torch]

My press didn't have enough stroke in the ram, and I had to add & remove spacers to make the full cut.

I have the same problem with mine. I found it faster and easiest to start the broach with the hydraulic ram, then finish the stroke with the 1 ton arbour press. Slip in the shim, clean out the chips from the broach, repeat and done.

[warmstrong1955]

My press didn't have enough stroke in the ram, and I had to add & remove spacers to make the full cut.

I have the same problem with mine. I found it faster and easiest to start the broach with the hydraulic ram, then finish the stroke with the 1 ton arbour press. Slip in the shim, clean out the chips from the broach, repeat and done.

I've got a 3 ton arbor press, which is what I have always used here for broaching. That 3/8" broach in the pic is 14" long, and the hub is 3-1/4", so it was too tall for the arbor press. My plan was to do start with the hydraulic press, and finish with the arbor. Would have been easy...I thought. Well....guess my name is Simpson....not Samson.... I pushed with the hydraulic press till it stroked out, and moved to the arbor press..... and..... not enough oomph.
I had some round bosses layin' around, that were burned from the wrong material, so I just stacked a couple of them on the hydraulic press, and finished the push through. Flip the part, add a shim, and repeat, and repeat again. (2 shims) Lot easier to push on an air valve than pull on a handle anyway.


Bill

[Dan]

OIC!

Really does takes me some time to absorb and understand. But so cool. I do own a; http://littlemachineshop.com/products/p ... &category=
DI w/ magnetic base.

Was exhausted and over complicated this.

Makes perfect sense now.