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Slitting Cutter on Lathe- CI Metal for Cross Spacer; is a manhole cover worth $1200?

U

UptownSport

Cast Iron
Joined
Jul 25, 2012
Location
Cable WI
I need advice on a piece of CI to space up a vice, and just how sound this idea is.

I need to slit ~halfway a 5/8 6061 screw with a 1.125 head. I no longer have access to the Bridgeport, so I'm considering using one of the old lathes- Think Sheldon. I would use the cross to feed the vised piece into the cutter- Jaws parallel to cutter.

I read relevant parts of Tubal Cain's 'Milling in the Lathe' and think I understand. I need to make an arbor- I think that's straightforward enough- for use in a MT spindle collet.

Clearances
Cross to spindle Ctr: 3.625
Spacer: .75 (Where the CI Piece Comes in)
Vise OA Hght: 2"
Arbor dia (1/2 of this value): .625
=.25 vise to arbor clearance

Slitter Cut:
Cross to spindle Ctr: 3.625
Spacer: .75
Vise OA Hght: 2"
Slitter dia (1/2 of this value): 1.5"
= -.625 (Approx -.5625 needed) Head is 1.125 dia

Vise jaws should have enough depth to cut ~1/16" less than halfway.

Head (Half) 0.25
Screw (Half) 0.3125
0.5625
Diff from .625 0.0625
Screw (Half) 0.3125
0.9375

So, I'd have 1/16 of depths remaining.
Click to expand...

My thought was to space with a $84.38 piece of CI from McMaster.
McMaster-Carr
Is this how much CI costs? :eek:

There's details such as how I'm going tighten an arbor without a flats (no Bridgeport now, either), vise/tailstock clearance and length vs stability of the arbor. Then I'd be the newb taking a full cut with some wicked cutter...

I assume the CI finish is 'good enough' to use as a spacer.

How viable is the idea? I'm looking a few dozen pieces and thought it easier than a milling attachment.

Thanks as always
20191227_152638.jpg
 
I did something similar (if I understand you) a few years back. I chucked an ER32 straight shank holding an endmill in the chuck, and fed the screw in a facing cycle across the spinning endmill. Worked great. They were little thumb screws for like a computer monitor type plug.
 
sfriedberg said:
You don't have a decent file in your shop? No lathe collets to chuck an endmill in?
Click to expand...
Yes. And, yes. I don't have a way to fix the arbor to the cross.
I was planning on a hole for a spanner, perhaps, to tighten the thing.

digger doug said:
Why cast iron ?
Click to expand...
Well, I understood you were supposed to use CI, as opposed to steel in cutting machines, because it had vibration damping qualities... I've heard that perhaps a million times.
The cross, compound, etc. are all CI. Even the McMaster description I linked in OP says so, IIRC.

so I suppose I got that wrong, or it really doesn't matter?
If it doesn't matter, that'd be great.

Hardplates said:
If someone calls me retarded it wouldn't be the first time but......what does a $1200 manhole cover have to do with anything????
Click to expand...
My attempt at commenting on the seemingly absurd price of a little chunk of CI. 14 x $84 = about $1200 worth of iron in a manhole cover.

@Mike1974 Thanks- yes, I'm trying to dupe a horizontal mill, and do it without breaking everything.

So don't spare me, beyond crazy, and call the VA for a serious trauma bed reservation in the nut ward?
Or will it work if executed carefully?

I don't plan on having the arbor near this long, not having it interfere with the vise.
And the vise would be 90 degrees from photo, if you are following what I'm thinking.
Tubal Cain Lathe Horiz Mill Problems.JPG
 
UptownSport said:
Yes. And, yes. I don't have a way to fix the arbor to the cross.
I was planning on a hole for a spanner, perhaps, to tighten the thing.


Well, I understood you were supposed to use CI, as opposed to steel in cutting machines, because it had vibration damping qualities... I've heard that perhaps a million times.
The cross, compound, etc. are all CI. Even the McMaster description I linked in OP says so, IIRC.

so I suppose I got that wrong, or it really doesn't matter?
If it doesn't matter, that'd be great.


My attempt at commenting on the seemingly absurd price of a little chunk of CI. 14 x $84 = about $1200 worth of iron in a manhole cover.

@Mike1974 Thanks- yes, I'm trying to dupe a horizontal mill, and do it without breaking everything.

So don't spare me, beyond crazy, and call the VA for a serious trauma bed reservation in the nut ward?
Or will it work if executed carefully?

I don't plan on having the arbor near this long, not having it interfere with the vise.
And the vise would be 90 degrees from photo, if you are following what I'm thinking.
View attachment 294504
Click to expand...

I'm sure this is covered best over at the homeshop forums.
 
This IS just one part I produce and sell, along with others.
The Sheldon was unquestionably used in production, and has been around as long as anyone here.

I Don't have access to the shop right now (C-Virus), and am looking at using what I have as an expedient until this madness ends. Otherwise i'd just do what I've always done and slit it with an end mill in the Bridgeport.

There are two threads here (at least) on milling attachments- That's where you suggested the Tubla Cain Milling with a lathe book.

If I broke some rule or it's a bad idea- Just kindly say so, and why if you'd please.
It's definitely not something someone would do in a home shop.
 
Ok, I get it. No one does this.
There is an ancient US Machine mill with BS 9 taper that's so far back in the shed I don't want to think about it.

Hey, you can't blame a guy for having ideas.
 
not sure if i understand what you are doing, but can you thread a hole in a piece of rectangular stock, attach it to cross slide and space it up correctly for the slitting saw in the chuck?
 
UptownSport said:
Ok, I get it. No one does this.
There is an ancient US Machine mill with BS 9 taper that's so far back in the shed I don't want to think about it.

Hey, you can't blame a guy for having ideas.
Click to expand...

No one does this here...they doo over at the homeshop forums.
 
Looks like a cable adjuster. 5/8ths thread? Must be for a Harley. Although you probably wouldn't use aluminum for that. Doesn't Chrome well.

In all seriousness, holding it lengthwise on the shank isn't a great idea for 2 reasons.

1) When you cut through it's going to spring shut and reduce the hold of the vise.

2) When it springs shut it's gonna pinch the slitting saw. 1+2 rarely comes out well.

Using a small endmill works OK because the cutting force is less, and when the screw springs shut there's only the little bit of cutter to get pinched, and it can cut it's own clearance.

I'd probably look at a fixture block with a hole bored to fit the shank of the screw. Butt the head against the side and figure out some way to keep it from rotating. Maybe a simple clamp plate and screw. A setscrew maybe not so great. Threaded in as 'dian' suggested might be ok too. But torquing it in is gonna compress it ...

And I'd avoid a climb cut doing this on a lathe. Different application, different axis, and a different reason, but I learned the hard way as a kid that attempting a climb cut on a Maximat REQUIRES you use the lead screw to feed the carriage. Nothing broken, but a good deal knocked out of whack and a chewed up part. Even with, I still wouldn't try a climb cut again.
 
Get a machined CI angle plate and make yourself a lathe angle plate for milling, cross drilling, etc.

Works best right on the cross slide with the compound removed. If you have an endmill with a "V" point you can machine a shallow V that will be right at spindle center and is great for cross-drilling. You can also clamp that arbor in the slot and drill holes for a pin spanner.

IMO a man without a mill absofrigginlutely needs an angle plate for his lathe and they are cheap and easy to make. Easy enough to tap holes for clamps where needed and the low cost and easy fab make you less reluctant to customize for a special job.

PS: A fly cutter will not stress a less than rigid lathe for facing the same way a face mill will. Also, pay attention to feed direction so the cutter pushes down on the carriage as it feeds into the work, for the same reason rear facing cutoff tools work best on small or older lathes.

What I'm saying is; make the angle plate first so you can make your slitting arbor and fixture. Also make sure the slitting cutter feeds so it pushes down. I use a Morse taper slitting saw arbor on the lathe all the time. It beats tearing down a setup on the mill. It's not that I'm lazy it's just that I don't like to work too hard.
 
As you can see, some people are responding in a positive manner to your inquiry, while others(?): not so much.

Pay attention to the former and ignore those who are no help at best and are insulting and demeaning at worst.

Dan
 
DanLinsch said:
As you can see, some people are responding in a positive manner to your inquiry, while others(?): not so much.

Pay attention to the former and ignore those who are no help at best and are insulting and demeaning at worst.

Dan
Click to expand...

Don't let the door.....
 
wesg said:
Looks like a cable adjuster.

In all seriousness, holding it lengthwise on the shank isn't a great idea for 2 reasons.

1) When you cut through it's going to spring shut and reduce the hold of the vise.

2) When it springs shut it's gonna pinch the slitting saw. 1+2 rarely comes out well.

Using a small endmill works OK because the cutting force is less, and when the screw springs shut there's only the little bit of cutter to get pinched, and it can cut it's own clearance.

I'd probably look at a fixture block with a hole bored to fit the shank of the screw. Butt the head against the side and figure out some way to keep it from rotating. Maybe a simple clamp plate and screw. A setscrew maybe not so great. Threaded in as 'dian' suggested might be ok too. But torquing it in is gonna compress it ...

And I'd avoid a climb cut doing this on a lathe. Different application, different axis, and a different reason, but I learned the hard way as a kid that attempting a climb cut on a Maximat REQUIRES you use the lead screw to feed the carriage. Nothing broken, but a good deal knocked out of whack and a chewed up part. Even with, I still wouldn't try a climb cut again.
Click to expand...

Thanks! That explains it. And yep, pretty close, LoL.
No power cross on a Sheldon.

Scottl said:
Get a machined CI angle plate and make yourself a lathe angle plate for milling, cross drilling, etc.

Works best right on the cross slide with the compound removed. If you have an endmill with a "V" point you can machine a shallow V that will be right at spindle center and is great for cross-drilling. You can also clamp that arbor in the slot and drill holes for a pin spanner.

IMO a man without a mill absofrigginlutely needs an angle plate for his lathe and they are cheap and easy to make. Easy enough to tap holes for clamps where needed and the low cost and easy fab make you less reluctant to customize for a special job.

PS: A fly cutter will not stress a less than rigid lathe for facing the same way a face mill will. Also, pay attention to feed direction so the cutter pushes down on the carriage as it feeds into the work, for the same reason rear facing cutoff tools work best on small or older lathes.

What I'm saying is; make the angle plate first so you can make your slitting arbor and fixture. Also make sure the slitting cutter feeds so it pushes down. I use a Morse taper slitting saw arbor on the lathe all the time. It beats tearing down a setup on the mill. It's not that I'm lazy it's just that I don't like to work too hard.
Click to expand...

Thanks, I think I understand, both your comments makes sense of the following. End mill, an angle plate, some type of vise sounds like the best idea- versus sawing- and no need for an arbor.

A lathe isn't a horizontal mill.
The third difficulty is that due to the direction of rotation of the cutter the work ought to be fed from the back of the lathe to the front. The cutting forces then tend to be upwards, but the saddle is designed to take downward thrust.
Click to expand...

DanLinsch said:
Pay attention to the former

Dan
Click to expand...
Thanks, I'm not looking for any trouble. That C-virus made everyone a little testy. They burned my city down, so some a lot ...
 
In answer to your original question.....probably yes.....all the municipal WS&S stuff Ive seen is astronomical prices,I suspect because the Lord Mayor and council have to get a cut ......Once I damaged a Tyco long radius 4" bend ....and was informed the thing cost $1800......Incidentally Tyco pocketed some $4 billion for supplying rolled /concrete lined steel pipe for the SE Qld "recycled water grid"...However,due to politics and fear campaigns ,the grid is in fact $9 billion wasted lying buried in the ground unused ......the religious right ran adverts like a girl turns on the kitchen tap ,and has a turd floating in her glass of water...Effective.
 
LoL, I bet.

A little go no-go gauge for one of the machine guns slipped out of the tank's compartments. It was some astronomical three digit price-
We hand cranked the turret around, and at somewhere around 358° finally found it laying in the sub turret hull!

Hey, thanks again all!!
 
Complete! Thanks, slick as snot. Results good as the 3200lb Series I CNC!

Bought a cheap AXA on the premise it wouldn't be hardened well so i could cut a trough in it.
It was off at least .007 end to end

I used Dihydrogen Oxide pipe slice as a jaw and added dimples to keep it captive.

wesg said:
1) When you cut through it's going to spring shut and reduce the hold of the vise.

Using a small endmill works OK because the cutting force is less, and when the screw springs shut there's only the little bit of cutter to get pinched, and it can cut it's own clearance.
Click to expand...

This is exactly what happened. The 2d allen was loose on each occurrence, while the nearest the head (1.125 couldn't be 'sprung') was tight.

20200806_145433~2.jpg20200806_131050~2.jpg
 
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