View Full Version : NFG needs advise on lathe tooling &tool post

03-03-2008, 09:55 PM
hi guy's, I have a logan 920 with a homemade quick turn tool post on the carriage and, i also have a compound with the old school lantren post tool holder.I bought this lathe with alot wore out mismatch size hss tooling. I tried shapeing some of the cutters with not much luck. My questions are ..
1 should i go with a quick change tool post? what the differents between piston vs wedge?
2 what kind of tooling high speed steel, carbide tipped, or inserts?

thanks daye

03-03-2008, 10:21 PM
The QC tool post is handy and a AXA would fit your lathe and you can get a Phase II for less than $100. The wedge is supposed to be better but I have used both and they seem ok. I must say I have the wedge but it is important to keep the chips out of either one. Just blow it off before you remove the holder from the tool post.

03-03-2008, 10:39 PM
The advice I was given when I joined was learn how to grind. 1/4" HSS is preferred even if you have to shim because you don't have to spend several hours working (or waiting for the wheel to work) on it.

I was told I'd chip up too much carbide before I learned what I was doing, and if my HSS regrinding is any indication, those individuals know what they are talking about. :D

I have to say grinding makes me think about more than I would otherwise, and I can foresee a day when I'll be looking for inserts instead, but that will be a while yet.

I've currently got a 4 way tool post, and I'm looking at QCTP, but I have a 4-jaw chuck or two to get out of the way first.

$0.02 and suffering under heavy inflation...

03-03-2008, 10:42 PM
Hi and welcome. I've given this advice before but go to the Alibris website and get a text called Technology of Machine Tools by Krar and someone, don't have it in my hand now but he's had a few partners in various issues. It really helps you understand the shape and action of cutting tools. I taught from it and it is a very useful text. You can find them for around $10 if you happen to look at the right time. Enjoy, I've been machining for over 60 years and still enjoy it. Peter

03-03-2008, 11:09 PM
The QC tool post is handy and a AXA would fit your lathe and you can get a Phase II for less than $100. The wedge is supposed to be better but I have used both and they seem ok. I must say I have the wedge but it is important to keep the chips out of either one. Just blow it off before you remove the holder from the tool post.

that's the one i got, the AXA Phase II wedge. the piston one may have been $10 cheaper or something, but most folks seemed to recommend the wedge. i've tried my best to break it, and it has held up perfectly. :)

just get plain old HSS cutters for now. they are pretty cheap and not much trouble to sharpen. i picked up one of those Harbor Freight cutter grinders on sale a few years ago, and it was a good investment. i have a few carbide cutters, and some of the insert tooling, but i don't bother using them because i am still learning and tend to ruin a lot of cutters. HSS is cheaper and easier to resharpen.

andy b.

03-04-2008, 01:03 AM
Howdy, Enco has the Phase II Piston type (100 AXA 9-12" swing) 6 pc. set on sale for $89.95


Forrest Addy
03-04-2008, 01:39 AM
Time, experimentation, and som mentoring will lead you to what works best for you. Remember that a Logan is a small low power machine built for hobbyists and schools where low first cost and skill development, not production were primary considerations. You may not be able to take full advantage of carbide tooling on you logan because you have neither the speed, power or rigidity necessary. I suggest HSS tools out of either a tool post and rocker or the smallest quick change holder as being the most likely to provide you with the best tooling combination.

Once you learn the basics of cutting tool geometry and how to free-hand grind them you will be well on your way to making parts productively on your Logan. The early skills can seem to be the most difficult to acquire.

Some Logan owners might interpret my words as a sneer at their favorite machine. Not so. Merely dispassionate observation tempered by considerable experience. I first learned to run a lathe on a South Bend in my Dad's basement so I'm no stranger to older home and school grade machine tools. I know very well what they can and can't do. I've also run the best and the worst machine tools and most every thing in between. Old iron when it's in good shape is a pleasure to run. Even if you don't have the power and speed of a production lathe or a toolroom lathe you can get good result from them using HSS tooling with only a little more time.

I suggest you stick with the tool post and rocker until you get a little practice. There's no rush to getting the latest and greates goodies. When re-setting your tools every time you change them drives you nuts then is to time to get the CQ tool post. Remember there's not much room on the compound of that Logan of yours for a blocky QC tool post. Maybe by the time you decide you really need one you might elect to make one of your own design about 3/4 the size of an AXA. Call it an "AAXA" and gear it toward 1/4" tool steel.

Who knows; you may want to move up a lathe size or three as your skills and the scale of your projects grow.

03-04-2008, 07:52 AM
The Aloris style QC tool post is one of the single best investments a lathe owner can make. It adds rigidity and easy, repeatable set up to the lathe not possible with the lantern style toolpost and removes one more variable for the beginner to overcome.

The AXA size will fit that lathe and can be transferred to lathes up to 12" or so. The choice of piston or wedge is a matter of economics in the home shop, either will work well, the wedge giving a bit better repeatability.

Do use HSS tooling and learn to grind it properly. In this size and class machine it will give much better performance than carbide.

03-04-2008, 08:24 AM
Learn to sharpen HSS. I use 1/4" square bits in a toolholder with a rocker toolpost and in 30 years have never felt any particular need to get a QC toolpost. I've always thought the money could better be spent elsewhere...but maybe I don't know what I'm missing.

The wedge type is in theory more repeatable than the piston type, but for a home shop I have trouble imagining why it would ever matter, or why repeatability of tool position would ever matter, at all, except in terms of center height adjustment.

03-04-2008, 10:13 AM
If your Logan is a flat belt drive like the one I had then if you overload the cutter it will kick the belt off and as Forrest said it is limited in depth of cut and feed by the flat belt.

I never replaced the lantern post on my Logan and it does a fine job. I used 1/4" HSS and carbide tools with it but the holders for the HSS and carbide are different. They are nice lathes but do have limits so be careful to not expect heavy cuts, but you can get very nice and accurate work.

I suggest the Atlas book, How To Run A Lathe, it's a good book.

Your Old Dog
03-04-2008, 10:56 AM
The QC tool post is handy and a AXA would fit your lathe and you can get a Phase II for less than $100. The wedge is supposed to be better but I have used both and they seem ok. I must say I have the wedge but it is important to keep the chips out of either one. Just blow it off before you remove the holder from the tool post.

According to the ad I looked at, the wedge is only better by .0002. I'm okay with the lessor quailty, inferior piston type. It has done more to help my lathe work then anyting else I've done.

03-04-2008, 11:17 AM
I just spent $40.00 and bought a lifetime supply (70) of 5/16" hss tool bits. I know that 1/4" is preferred, but since these were "odd-size" they were inexpensive. They were Rex aaa by Colt Industries, and from the box, I guess they are elderly stock. I have noticed that the branded stuff is definitely superior to the chinese Busy Bee specials and this was cheaper. Where?-Plaza Machinery, a HSM advertiser.

03-04-2008, 09:47 PM
thanks for the advise guys! I think that sticking with what I got and learning how the grind is good idea . What grit wheel should i use? si a 8'' bench grinder ok too big or small?

forrest andy your right on about the lathe. I like the lathe but, after only two months I would like to up grade. the big 8'' 4-jaw take long time and some belt slipping to get moveingbut , it will do for now until I learn more about machineing and other lathes. Only one way the learn... thats to do it. thanks, daye

J Tiers
03-04-2008, 10:31 PM
You gotta know HOW to get the power to the work.

You can get about 1 HP through that belt, but it's gotta be moving fast. So that means you may want to use back gears for some cuts, starting from higher speeds on the pulleys.

The machine has 3 low range speeds, and 3 more in back gear. Use them. (12 speeds altogether, but the high range makes the back gears sing pretty loud, so I don't do that, and rarely use the high speed range at all)

My 200 has no trouble taking a DOC of up to 1/8 or more, but you can't do that at high speed. It just ain't a Springfield.

If you want to use an 8" chuck on that size machine, well, anything you wanna do is OK by me, but the "right size" is 6". The machine isn't at fault just because you use too big a chuck and want to wind it up to a high speed.

As far as carbide?

Sure, you can use it. If you need it for a resistant material, just use it and take smaller DOC at higher speeds. Or go slow if that seems better to you.

The Logan IS a lightER weight machine, but I would never call it a lightWEIGHT machine as long as there are Atlas or small Southbend machines to compare it to.

The Logan bed is 7" wide, the Southbend my Dad-in-law has is barely 5" wide, and at least a half inch less deep. I can pick up similar Atlas or Southbend, but the Logan is too heavy for me.

So you can get away with things on the Logan that you can't with Atlas etc. But, yes, it is certainly no Sheldon or Rockwell.