Monarch c cutoff problems!

Hi I have a 1941 monarch C 14.5x30 she's been great made many new parts with her but my biggest problem to this day is parting off with my cross feed the slowest feed is .0028 at first I thought it was my tool holder so this morning I built a rigid parting tool holder. I'm cutting 1.5 dia. Cold roll if I feed it by hand it's great but using the cross feed it takes too much I'm using 1/8 x 7/8 has parting tool I've tried flat, angled pointed relieved grind parting tool. I've tried above center,at center below center different combinations. I think .0028 is to much feed for hss but back in 1941 that was mostly what they had so how did they efficiently part off I don't want to hand feed all my parting operations.IMG_20130802_121018_727_zps18724210.jpg Photo by dieseltom | Photobucket

Have you tried an inserted cut off tool?
I routinely cut off on my 12" CK without any problems using an inserted tool. If I try using a HSS tool, I have all kinds of problems. Gave up on HSS years ago, and never looked back.
Harry

I'll buy one and try it but I'm still confused 72 years ago I don't think carbide was used too much if at all. .0028 per rev is even on the high side for carbide isn't it?

May be simplistic but I can't tell from your photo. On my cutoff holder, the side of the holder is square, but my cutoff tool is tapered, so I have to be careful when I set it up that I have down clearance on both sides of the tool (which means the base of the tool is going to be off the holder just a bit).

Another thing I will do is indicate the tool (holder and all) so that it runs parallel with the cross slide. You can check by mounting the indicator on the chuck (or the fixed part of the apron) and crank the handle of your cross slide back and forth, indicator on the tool itself. You want there to be a minimum if any runout (its a pain but I shoot for 0).

May be simplistic but those two things get a lot of people. I have come across some brazed cutoff tools- there is a brazed carbide strip on the top of the tool. They work very well for heavy cutoff work. 0.0028 is not all that heavy, however, and not sure about the Monarch but on a lot of lathes, the cross feed is half the given feed on the length- in other words, if the selector says .0028, then on cross it will feed .0014.

I am wondering if your tool is long enough? There is not all that much being held in your holder (which looks pretty awesome by the way). Looks like if the tool was half again longer it would help it a bunch. When cutting off, any place that can flex will. I am also wondering about how far your holder has the tool from the center of the post. Lots of coolant I might add.

Hopefully this is not too simplistic for your experience, for all I know you may have more experience than I do. I have been running production on a manual lathe lately, parting off anywhere from 1-2" in diameter running 560 rpm with a cross feed something like you're describing (using the brazed parting tools). Using a CXA type holder (compound not extended at all for rigidity), and lots of coolant. I inherited the job from someone who was running the rpm like that, so that's what I have continued to do over the last several weeks and have gotten good results. When the finish starts getting poor, I sharpen things up and reset the center height, going for the exact center line. Been doing this a lot of years, but parting was always my weakness!

I had the same thoughts as you about HSS, but I gave up after trying the inserts.
.028 is probably a light feed, and the other surprise is that carbide likes high speed, and coolant helps alot. Whatever you do, don't get the cheap stuff, get decent inserts and a good cut off tool. It's going to cost, but worth every penny.
I've got a Manchester holder, 2-1/4" capacity, on my CK. IRCC it cost upwards of 200.00 and the inserts, 1/8" wide, are about 10.00 each in packs of 10.
1-1/2" D, I would cut that off at 5-800 RPM, hand feeding about .003-.005" wet. The only reason I don't go faster is the coolant mess, even with the guard. When I had turret lathes, I would hold the stock in collets and run at 1500 RPM, power feed it at about .004", and the tool was in the rear position upside down.

On Monarchs, the cross and longitudinal feeds are the same.
I'll try and get some pictures tomorrow.
Harry

Okay I'll be ordering a new inserted carbide cut off tool Monday which grade of carbide should I get I only have 500 rpm until I make bigger set of shive's for the old girl. Any suggestions since were on the coolant subject my garage freezes in winter so should I go with strait cutting oil or does someone have any suggestions. The cut off blade is indicated to zero tried to cover all the bases, I'm using the stepped parting tool but I'll try relieving it some more I'm also pouring cutting oil on. But in 1941 I'd like to know what they did for parting off.

It just your tool holder is hung out to far. you can part at the same speed and feed you turn at it's all about taking the spring out your set up. and just put it on center if it wants to chatter go faster. HSS 100 fpm

Admittedly, the Manchester holder in the following pictures is probably more than you need, but it does illustrate some important points, mainly the rigidity of the tool itself. When I first started using inserted holders in the early '90's, it was an Iscar blade, holder and inserts, the very basic style. The blade was/is adjustable for stick out in the holder, but the biggest problem I had was the seating pocket and the insert. There was no positive stop on how far in the pocket seat the insert would go. I think that problem has been solved in the evolution of that particular style, and it is probably the most common insert holder available at reasonable costs. I bought the Manchester holder set, because at the time I was running a lot of production on turret lathes, and the Iscar style was causing all sorts of problems, from short insert life, damaged blades, push back in the pocket seat, etc. As a result of the experience with the Manchester tool, all my lathes got that type of holder. At the time I had seven lathes, including the turret lathes. It was a sizable investment, that I don't regret.
The type of Manchester holder is in their Seperator line, the largest I had were the 3" size for the 16" Monarchs and the #5 J&L turret lathe, and they were sized for the machine, as were the others.
The holder I took pictures of today is the 2-1/4" size on my 12" CK on the CXA toolpost, and I did check the 2012 price in the MSC catalog, approx 280.00. The little Manchester holder I use on the EE is about 100.00.






The insert poscket has a prismatic groove for the insert. Notice that the blade is thinner than the inset, and the insert is wider at the cutting edge and tapers back. It also forms the chip into a narrower width to get out of the groove.
The wear mark on the blade's side is because I had the reset the compound rest, or the toolpost incorrectly
Harry