# Does this look like it'll work?



## jwmay (Jul 25, 2021)

Yeah I get it. Been kicking around here for years, and still need advice. Sorry. I'm slow.

I'm making something for my Dad. He looked for two years to find this weight. I figure now is the time to make sure I'm not going to ruin anything. Tolerances on this are pretty well non existent, but I don't want it to be ugly. And I don't want to make a mistake that'll ruin it.

I'm about to very slowly feed this 1/8" thick 4 1/4" milling cutter held in an R8 slitting saw arbor 5/8" deep into this block of cast iron with a spindle rpm of 140 and then run it 9" across. That's the bottom limit for rpm. The calculator says I'm spinning about twice as fast as I should.
Option 1 is do it and see what happens.
Option two is use a .045 thick slitting saw that isn't large enough to get 5/8" deep. 
Option three is whatever you all can agree on.
Does it look like my clamping is sufficient? 
All input welcome!


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## markba633csi (Jul 25, 2021)

You can't do what you want to do with an endmill?
I'd probably go with the thinner blade if you must use a saw
-Mark


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## jwmay (Jul 25, 2021)

I just thought it'd be quicker to try to cut out as much material as I could. I'm open to suggestions. This is the original part. This shows what I have to remove I hope.


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## jwmay (Jul 25, 2021)

And if a Mod happens by this way, Doors is supposed to be does. Stupid technology always making me look dumb.  At least I think that's right.


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## rabler (Jul 25, 2021)

If you use the "edit" option at the bottom of the first post, I believe you can change the title.


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## sdelivery (Jul 25, 2021)

Since you can't lower your rpm do you have a smaller dia. Cutter?
If you can't  lower the rpm ( I think you are going to see a lot of chatter)
I would probably take less depth of a cut but you need to maintain the tooth loading so that means faster feed....hence my suggestion for less depth of cut.


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## jwmay (Jul 25, 2021)

Less DOC and higher feed rate. Ok I can do that probably.


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## Ianagos (Jul 25, 2021)

Well not 100% sure what you are trying to do but your quil is extended waaay out there. And that’s a very large cutter for an r8 arbor so I suspect that won’t be the best setup. 

Now I can’t really recommend anything better as like I said I don’t understand the goal.

I try to stay away from slitting saw and the like as much as possible. I’ve never had great luck with them seems like a endmill would do what you and doing with the saw if you reorient the part. Will probably make for an all around more stable setup.


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## ErichKeane (Jul 25, 2021)

What material is that  wheel?  You might find that swapping it to a carbide tipped cutter (like for a small woodworking tool!) will make the cut better at the higher speeds.


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## MrWhoopee (Jul 25, 2021)

To edit the thread title, click the three dots in the upper right and select "Edit Thread"


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## sdelivery (Jul 25, 2021)

I see your just trying to remove a large peice that could be quite desirable in the near future instead of just turning it into chips.
First I would rather use a saw but you might not have one available so I  like the slitting saw for this purpose because of the design verses a small end mill. It would likely break.
Speed Kills- You should think about a spray bottle with the appropriate coolant.
I  would like to see a stop on the table at the bottom of the part in the direction you intend to feed in.


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## sdelivery (Jul 25, 2021)

Another thing I just noticed is the face you intend to cut on is "lumpy "
I would touch the cutter off on the highest  mountain set zero back away and start your first pass from that touch off. Increment in until you  are cutting all the was across, it is tempting to touch off on the lowest valley but that could have the cutter deeper than it cares for when you hit a mountain.
Kerosene is good coolant for cutting cast iron.


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## jwmay (Jul 25, 2021)

You are correct. I should have a nice  9"x1"x3/4" rectangle of cast iron for myself when I'm done. Instead of a big pile of black dust.  
I should have waited, but I got started already by chain drilling inside one of my layout lines to about .030" shy of full depth. I did break a drill bit. So now I'll have that to contend with as I move forward. 
I do have a pretty good horizontal bandsaw, but it balks at 9" long cuts. It's a 7x12, but I kinda think they're talking about square tube when they give those numbers. 2x4 seems to be the most it'll take. And the down feed cylinder isn't working right, so I'd have to lower it by hand.
I do have a small block of material clamped in the corner to counteract cutting forces, but I may not have gotten it in the picture. Keep 'en coming guys! I might just succeed in this after all!


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## jwmay (Jul 25, 2021)

Actually I just put a new blade on the saw. I probably should have started there. And it's a TIN coated HSS milling cutter. I didn't buy it on purpose, but since I have it, it was a thought. I was nervous about it for my little machine, so figured I'd ask.
I'm going to revisit the bandsaw idea.


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## Winegrower (Jul 25, 2021)

I think most of machining is giving it a shot in a non-destructive way, see what happens, correct and repeat.


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## 682bear (Jul 25, 2021)

If you proceed with the slitting saw, I would advise running the slowest speed possible, DOC at .100, and start at a low feedrate... after it begins cutting, bump the feed up until it just begins to chatter, then back down until the chatter stops...

I don't know what type of mill you have... the DOC may be too much, or you may get away with more... I'm a 'try it and see, then adjust as necessary' machinist... or a 'seat of the pants' machinist if that makes sense...

One thing that hasn't been mentioned... if the part is a rough casting, the outer surface may be extremely hard. If so, you may very well scrap the saw no matter what you try... It would be better if you could get the speed down to 60 or 70 rpms.

Good luck...

-Bear


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## Doug Gray (Jul 25, 2021)

In the mill setup shown, spindle stick out is huge. I always have my spindle completely retracted and lock when milling...no? Im talking smaller l r8 mill/drills.


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## jwmay (Jul 26, 2021)

Yep. That is a lot of spindle hanging out. I'll adjust that.  At the time of setting it up, I wanted the head up high.  I was planning to cut that slot, and then chain drill the top surface without having to move the work or the head elevation.
Thanks again! The whole plan seems to be evolving.


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## mattthemuppet2 (Jul 26, 2021)

I'd definitely go with the bandsaw first. You'll probably need to turn the piece around to cut from both sides, then finish the bit in the middle with a hand saw. It's a lot quicker, less effort and you're less likely to break something. Slitting saws take a bit of getting use to.


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## jwmay (Aug 3, 2021)

This was a good idea. Thanks!
I've been using this vise as ballast for my mill/drill for 4 years. I'm glad I finally found a better use for it.


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## jwmay (Sep 25, 2021)

Here's an update for all of you who've been on the edge of your seats waiting to find out what happened. Lol 
I used the horizontal band saw first. Then bought some extra long end mills. I tried plunging with little success. Unfortunately I'm as patient as I am stubborn. So I spent a few days slowly, carefully....painstakingly plunging 3/4" deep with the goal being a 1/2" wide by 1.25" deep by 9" long pocket. Finally I decided to take a stab at feeding right to left at .020" DOC. That worked extremely well. Except when the end mill hit something hard In the work, the clamps and fixturing collapsed, and the work started traveling across the table independent of the table. There's a picture below. I ended up getting my pocket done after maybe an hour except for one hard spot that just won't be machined. The piece isn't done yet, but the difficult portion is over. Due to the pieces purpose, I don't think this evidently unmachineable section will be a problem. There's also a void in the casting, which was full of tiny black balls that look like what I imagine gunpowder to look like. I'll take a picture if anyone actually is interested.


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## jwmay (Sep 25, 2021)

Here's the very benign looking picture taken right after I smashed the emergency stop button.


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## mattthemuppet2 (Sep 26, 2021)

that seems like a painless way to learn the merits of stop blocks at either end of the work!


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## jwmay (Sep 26, 2021)

Yeah! Not only that, but I had been warned on the forum to put stop blocks down. And I had put on on the left side. I didn't get loose, but once the other clamps let go, it was overpowered as well I guess. 
Anybody remember that hard spot I mentioned? Sawzall with a bimetal blade took care of it. Here's the not yet deburred result with it's dimension donor. This is an obsolete antique tractor weight. Dad wanted one for himself. He didn't care if it was taller, or if the slot was exactly the same. But I tried to make it right. It's ok, right?


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## cwilliamrose (Sep 26, 2021)

jwmay said:


> Here's the very benign looking picture taken right after I smashed the emergency stop button.


I know it's hard to tell from the photo but it appears the hold down bars are bearing on the edge of the part instead of having the force out at the tip of the bar.



The toe end of the bar has a little slope that is meant to be the contact area and the tail end seems to be lower than the toe instead of being a little above the height of the part to get the toe in contact. Apologies if I'm wrong about what I'm seeing.


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## jwmay (Sep 26, 2021)

You could be right. I've taken it apart now, but it looks that way from the picture. That one stayed put though. It was there for something to register against if I had to take the part out and put back in.
I looked back at all my pictures, and I think I must be wrong about having used a stop block. I don't see that clamp I thought slid. Not only that, but I'd have had to move it the 9" or whatever back where it came from. So I bet I added the stop block after the malfunction. It's been on the mill table for 2 months, so it's possible I just didn't remember it right. I could have sworn I had one on the left though. Who knows?! I'll try to make sure I set up those clamps better next time. Thanks!


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## mattthemuppet2 (Sep 26, 2021)

that's a big piece of work, nice job. With clamping stuff it's always fine until it isn't  It's best to think of how things could go wrong and then set it up to prevent that. Also a shallow cut with a 1/4" endmill is very different to a 2" deep cut with a 1/2" endmill. Got to make mistakes to gain experience!


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## Just for fun (Sep 26, 2021)

cwilliamrose said:


> I know it's hard to tell from the photo but it appears the hold down bars are bearing on the edge of the part instead of having the force out at the tip of the bar.
> 
> View attachment 379829
> 
> The toe end of the bar has a little slope that is meant to be the contact area and the tail end seems to be lower than the toe instead of being a little above the height of the part to get the toe in contact. Apologies if I'm wrong about what I'm seeing.



So I have been wondering when you clam something like that what kind of torque do you put on the clamping studs?  I've never seen anyone actually clamping stuff down, I see it after it's clamped.  I'm assuming just a feel but tight.


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## Ianagos (Sep 27, 2021)

Just for fun said:


> So I have been wondering when you clam something like that what kind of torque do you put on the clamping studs? I've never seen anyone actually clamping stuff down, I see it after it's clamped. I'm assuming just a feel but tight.



But curious about this aswell but I think it is really part dependent.

I do very little work using work clamped to the table I try to use my vise in any situation I can. I’ve even made fixtures to bolt a large part to the table instead of having to clamp it with typical step clamps.

I have clamped one part in the last few years and I was a little worried that it would move but I was taking very very light skim cuts and that was all. So I used 2 3/8 bolt and didn’t torque them too hard. That held the part down safely and I was able to Machine it.


I have had a few parts pull out of a vise and pop off a vacuum Chuck and that almost always gets nasty quick. 

I’m alway on the line if I think it’s clamped hard enough vs not distorting the vise. Experience I the only way I think to master it.


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## 682bear (Sep 27, 2021)

Just for fun said:


> So I have been wondering when you clam something like that what kind of torque do you put on the clamping studs?  I've never seen anyone actually clamping stuff down, I see it after it's clamped.  I'm assuming just a feel but tight.



It is, IMO, part dependent... depending on the size/weight of the part, what type of setup, part material, what type of machining (light cuts, heavy cuts, cutting interrupted surface, etc), everything should be factored in.

A while back, I needed to skim a bore on the end of a Hendey lathe headstock... it was an 'iffy' setup... I needed a bigger mill table...







I had this clamped with two ½" studs... that's all I could get on it... I had the clamps *TIGHT*... 

It worked out fine... the 'pucker factor' was pretty high, though.

-Bear


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