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Notching Tube, Need Help/Ideas

angel0913

Plastic
Joined
Sep 8, 2019
Hi Everyone,

Racking my brain trying to make this work. I tried to make a post yesterday and attach photos but was unsuccessful so I'm going to do my best to explain what I'm currently doing and what I'm trying to do. Always open to ANY suggestions or ideas. Keep in mind I'm doing these hundreds at a time and need a more streamlined process.
I'm working with 1.50 O.D. .095 wall ERW steel tube. Cut down to size with a 45 degree on one end and welding a .125 thick, 1/2" wide tab across the open end, centered on the 1.50 diameter. I am currently grinding the notch for this tab to sit in, ideally this notch would be .125 deep, 1/2" wide, squared and centered but that is all but impossible with the bench grinder setup I'm currently using. Leaving inconstant depth, rounded notches (because of the wear of a grinding wheel) and slightly off center notches. Causing ALOT of unnecessary hand fitting, welding, grinding and finish sanding.
My current solution to this issue was to build a tooling jig to hold my pieces for constant cuts, combined with a Porter Cable 11A Router fitted with a 1/2" dia. end mill bit. In THEORY this would cut a nice clean, squared, centered notch to drop my tab into and weld. My problem with this is I don't know enough about machining/milling to know what kind of bit is best to use or if it'll work with the RPM of the router(27500rpm).
McMaster-Carr had too many options to choose from. What I ordered was a 1/2" dia. 4 Flute Titanium Nitride (TiN) Coated High-Speed Steel Square End Mill, it was burned up while trying to make a cut to the tooling jig, also mild steel but is .250 thick. It did make ONE cut through a test piece of tube and I was satisfied with the results but it would cut no more.
Any suggestions or other ideas would be great. The whole trial and error route is getting pretty expensive. I would like to find a bit that'll work without having to buy a dozen different kind of end mills. Thanks.
 
I thought his description was good. Photos help of course. The router spins way too fast for metal working. You will do nothing but burn up bits that way. You need some better tools to chose from. So far all you’ve mentioned is a router and a bench grinder. Hard to make much with that selection. What else do you have?


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Until you post some kind of pix, I'm going to suggest Vogel die.

Thanks, I'm working on trying to figure out how to get my pics to upload. I just looked up Vogel Die and that's almost exactly what I'm trying to do, you've got the right idea. It would be perfect if it would cut a 1/2" wide, 1/8" deep square corner notch. I'll give them a call on Monday and see if they've got or can custom make a die like that. Thanks for the idea and recommendation.
 
Not much else in the way of notching the ends of these tubes. A drill press, couple welders, few hand held grinders, belt and disc sanders, and a bender. I've already got routers for woodworking, I bought the Porter Cable to accommodate a 1/2" shank for these end mill bits. If you think that's a bad idea and wont work I'll look at other routs and ideas. Trial and error is expensive, that's why I reached out for suggestions form you guys with a little more know how and experience. Thanks.
 
RPM is more than 10 times what even a carbide EM will stand.

Got it. Just going to burn up bits as mentioned above. Did not know that. I was hoping there was a bit that could handle what I was trying to do. Going to scrap that idea, no need wasting time and money if it can't be done. Thanks.
 
RPM is more than 10 times what even a carbide EM will stand.

What RPM should I be looking for? Porter Cable also sells a variable speed motor that'll turn down to 10'000RPM. The reason I choose that route is because I've milled some aluminum lowers in the past with a trim router fitted with a end mill. Thought maybe if I got the right bit for steel it would work as well.
 
How are you cutting the 45 degree angle? You might be money and time ahead contracting it out. Pretty simple CNC job depending on the length of your tube.
 
How are you cutting the 45 degree angle? You might be money and time ahead contracting it out. Pretty simple CNC job depending on the length of your tube.

Started with a 14" abbrasive chop saw. Have since moved to a smaller cold cut saw to save time in die grinding the ends for cleanup. The cold cut saw leaves a nice clean straight cut where the abbrasive saw blade would bow slightly while cutting and left alot to cleanup when finished. I don't mind investing the time or money in setting this up just looking for better ways of doing so. Thanks.
 
As you have discovered, these speeds just won’t work for cutting steel. Light cuts in Aluminum can generally be accomplished with woodworking tools at near woodworking speeds, and in modern metalworking machines with through spindle coolant (6000+ lbs, 80k+$) these speeds can be approached in more stout steel parts, but no, not with a 100$ router.
A total rethink is in order. 10,000 rpm is still way too fast for an endmill in steel Tube. Also, The rigidity of the tube will limit how aggressively this slot can be cut with an endmill in any kind of machine. A notcher is one option, but it will inevitably distort the tube a bit, I don’t know how much of a problem that is for you.
Abrasive machining comes to mind, a 1/2” premium grinding wheel and a sliding self centering vise comes to mind as a cobbled together rig if you don’t have a milling machine.
 
I suspect that the op has got himself into the classic lots of volume, low margin, wrong for kit, no money to spend on tooling type of job.
Looking at the kit he has I would try this (purists please look away now)
If the drill press is reasonably rigid, make a jig to hold the tube vertically onto the table, put a 1/2" or slightly larger endmill in the chuck,run at low speed, perhaps 200 rpm to start with. Set the tube to a repeatable height by having a stop on the jig, wind the endmill down to touch the end of the tube then put a 1/8" spacer on the depth stop of the driller, make up a simple 1/16" c washer to fit under the depth stop so you can take two cuts, one with and one without the spacer.
We are now going to either swing the table or the head of the drill across the work, the idea is that the cutter will be pushed across the end of the tube by hand by swinging either the table or the driller head from one side to the other.
This is crude and against all best practices but if it works it will get you out of trouble. Then you can make enough to buy the proper machinery.
 
As you have discovered, these speeds just won’t work for cutting steel. Light cuts in Aluminum can generally be accomplished with woodworking tools at near woodworking speeds, and in modern metalworking machines with through spindle coolant (6000+ lbs, 80k+$) these speeds can be approached in more stout steel parts, but no, not with a 100$ router.
A total rethink is in order. 10,000 rpm is still way too fast for an endmill in steel Tube. Also, The rigidity of the tube will limit how aggressively this slot can be cut with an endmill in any kind of machine. A notcher is one option, but it will inevitably distort the tube a bit, I don’t know how much of a problem that is for you.
Abrasive machining comes to mind, a 1/2” premium grinding wheel and a sliding self centering vise comes to mind as a cobbled together rig if you don’t have a milling machine.

I have been dealing with the headache of my current inconsistent setup and you are correct a total rethink was in order. The end mill was what I came up with. The rigidity of the tube is solidly fixed to the router jig I've built. Looks like that's going to be scraped. As far as the abrasive maching as you call it, I'm pretty sure that's what I've been doing. Special ordered 1/2" grinding wheels from Grainger and set up a Chanel to feed the tubes into it. It's just not ideal. Looking for a more of a one and done considering the quantity I'm working with. Going to contact Vogal die Monday and see if they've got a solution. If not I may be shopping for a small milling machine. Thanks.
 
I suspect that the op has got himself into the classic lots of volume, low margin, wrong for kit, no money to spend on tooling type of job.
Looking at the kit he has I would try this (purists please look away now)
If the drill press is reasonably rigid, make a jig to hold the tube vertically onto the table, put a 1/2" or slightly larger endmill in the chuck,run at low speed, perhaps 200 rpm to start with. Set the tube to a repeatable height by having a stop on the jig, wind the endmill down to touch the end of the tube then put a 1/8" spacer on the depth stop of the driller, make up a simple 1/16" c washer to fit under the depth stop so you can take two cuts, one with and one without the spacer.
We are now going to either swing the table or the head of the drill across the work, the idea is that the cutter will be pushed across the end of the tube by hand by swinging either the table or the driller head from one side to the other.
This is crude and against all best practices but if it works it will get you out of trouble. Then you can make enough to buy the proper machinery.

You are partially correct. When I took this job it was manageable. However volume has increased and I'm just looking for a better more proficient way of getting this done. Money is always an issue but is there and I don't mind a bit investing it in the correct tooling but I don't want to waste it on bad ideas because lack of machining knowlage like the router idea. Using the drill press did cross my mind in a similar way that I decided not to go with as it's used pretty frequently. May work if I bought a dedicated press setup just for this process. I know a milling machine is most likely my best bet, but I've seen the prices on those and that I don't have the funds for. Thanks.
 
You are partially correct. When I took this job it was manageable. However volume has increased and I'm just looking for a better more proficient way of getting this done. Money is always an issue but is there and I don't mind a bit investing it in the correct tooling but I don't want to waste it on bad ideas because lack of machining knowlage like the router idea. Using the drill press did cross my mind in a similar way that I decided not to go with as it's used pretty frequently. May work if I bought a dedicated press setup just for this process. I know a milling machine is most likely my best bet, but I've seen the prices on those and that I don't have the funds for. Thanks.

Get yourself another bench grinder. They are cheap enough.

With four stones mounted along with suitable jigs, the notches could be run in a progression that left only little material removal for the final wheel and so preserve the sharp corner you desire.

Less than $100 and some woodwork should do it.
 
Might would be cheaper and easier for now to send them to a machine shop to get notched. I cant imagine it being a few bucks a notch.
 
That job is screaming 4th axis on a plasma table. I would charge around $1 to $1.50 each to do a job like that in any kind of volume. Surely your time is worth more than that, sub it out to someone equipped to handle the job efficiently.
 
I suspect that the op has got himself into the classic lots of volume, low margin, wrong for kit, no money to spend on tooling type of job.
Looking at the kit he has I would try this (purists please look away now)
If the drill press is reasonably rigid, make a jig to hold the tube vertically onto the table, put a 1/2" or slightly larger endmill in the chuck,run at low speed, perhaps 200 rpm to start with. Set the tube to a repeatable height by having a stop on the jig, wind the endmill down to touch the end of the tube then put a 1/8" spacer on the depth stop of the driller, make up a simple 1/16" c washer to fit under the depth stop so you can take two cuts, one with and one without the spacer.
We are now going to either swing the table or the head of the drill across the work, the idea is that the cutter will be pushed across the end of the tube by hand by swinging either the table or the driller head from one side to the other.
This is crude and against all best practices but if it works it will get you out of trouble. Then you can make enough to buy the proper machinery.

You've got to be kidding....

Please go back to the harry homeshop forums sir.
 








 
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