How to cut a Radius

hi my name is Dale and welcome to metal tips and tricks I've got an exciting little trick to show you on the milling machine I'm sure you're going to love I had this part come in today and it it's not a hard part to do it's made out of plastic we're going to make it out of steel well when I made this part you know you look at it's not that tough you break it down it's basically a rectangle with two holes drilled in it and a milled slot here very easy until you get to this radius and that is something that's frustrating to me because it takes so long to set it up on the rotary table and do it that way I wanted to come up with a faster easier way and as you know every day is a school day in the machine shop we're always learning something new well I started to think about it and came up with a different way to get that radius I think you guys are going to like now one thing about this radius is almost all these have something in common is there's always a hole in the center that we can pivot from and that's what we're going to take it a take of advantage here we've got a block here I've just kind of cut out to show you this tip and what we're going to end up doing is putting a pin in it now you see that pin rotates now the distance well actually let me put it in here and show you what we're going to do is we are going to put it in the vise and we're going to turn it and just keep cutting it and putting multiple facets on the radius now some of you're going to say well the distance from this Center to this will keep changing as I rotate it but if you look at it as I rotate this pin you can see the center mark right there is always at the same height therefore we can assume that as we rotate the part pivoting on this that Center and that edge will always be the same distance so let me show you how you do this first we have to line up the part so we know that the cutter is right on this edge let me bring this up a little bit see how this is just kind of loose if I go in with a cutter especially like a - flute cutter I just lower the cutter in it and it's set we tighten the quill tighten the vise now we're going to be a little too tight a little too tight from what I want to do so we're going to lower the knee down we're going to Center the dial put it on zero I'm going to lower the knee take out the backlash come back up and we're going to stop about mm right before zero right there don't forget to turn your handle around the way to the handle can vibrate and cause your needle lower and we don't want to have that happen now we've got about two thousand seven inch clearance and we can start cutting let me put some safety glasses on or my glasses in this case so what I want to do is back this off and we're just going to rotate that a bit and I'm going to bring it into the vise quite a ways so I am got as much material clamped as I can turn this on now get ready guys going to shoot some chips your way now you can see the facets and the radius starting to develop we're going to turn around to the other side don't have to remeasure we just have to start cutting you can now see how that radius is developing but now we have a point on the top that we have to eliminate well your machinist guys think outside the box I'm showing you the pin on top let's change that around and let's go this way we're going to realign we're going to pick one of those facets come up to there back it off a bit I'm going to tighten the table and now we're going to switch handles that we're going to turn so again it's the same theory keep that pin tight against the vise so now for all you trolls I gave you some really good food on that one didn't I to be safe I should have shut off the machine on each facet that I cut I didn't do that for a reason because of time but look at how that is right now and that nice now at this point if I want to make that better I just have to put it back in the mill and start knocking off the high points at this level of the job I could go to the grinder or belt sander writing that off I could file that it just matters how accurate I need it so let's look at it with a radius gauge that's a pretty nice fit think how fast that was now if I want to I could go in there and really clean up in X ink you know let's do it so there we go just a matter of minutes that's a pretty nice fit there's room for improvement but the concept is strong now look at all those little facets there there's so many that I can probably just take a file and eliminate them quickly look at that just a matter of minutes so there we go guys that's my tip for the day of how to make a radius now if you haven't subscribed to my channel please take the time to do that I'd really appreciate that please give me some thumbs up also leave some nice comments for me love to hear from you alright guys until next time go out in your shop build something cool thanks just like I did with the other bit is I get a depth of a thousand seventy seven thousand I did a depth a bet good ffff I did a depth that was a lot I did a depth that was somewhat deeper than it was

Channel: Build Something Cool

Views: 1,663,367

Rating: 4.8876367 out of 5

Keywords: Dale Derry, Metal tips and tricks, Radius cutting, Milling machine, Bridgeport, Bridgeport milling machine, Kurt vice, Machinist Bice, Machinist vice, Radii, Cutting radii, Steel part, Plastic part, Drill holes, Milling tip, Milling tip 101, Milling machine tip 101, Do It Yourself (Hobby)

Id: hTj6LC6agrg

Length: 9min 47sec (587 seconds)

Published: Fri Sep 25 2015

Reddit Comments

[u/[deleted]]

Before I clicked: Not one of these again.

After the first trick: OK, that's pretty neat, but he should have chosen a shorter block to demo.

After the second trick: OMG.

After the radius gage: faints

[u/nikolaiownz]

Fast not really. But it works :-)

[u/rainbowdongs]

That's pretty clever!

[u/86maxwellsmart]

If the demo material shown was the actual part, i.e. the aluminum piece, I would just use that radius gauge to scribe a line for the radius, cut most of the material away with a band saw, then finish with a belt sander. In fact, I have used the method for heavy gauge sheet metal covers. But I think his method would be better for the actual, thick steel part that he was planning on making. And, of course, at work I have access to CNC mills which would make the job very easy.

[u/I-r-machinist]

This tip is great for two scenarios - one being the home shop guy without a CNC or rotary, and two being the job shop tasked with cheaply reproducing an inherently loose (.005 or .01) tolerance part. I have a few parts like this to make coming up at work for a prototype, and you bet I'll use this method if our only CNC mill is tied up. Thanks for posting, OP.

[u/I-r-machinist]

http://m.imgur.com/a/FAzBw

Here ya go. I gave it a shot. Holes are just a 1/4 shorty split web shoved thru, and then I set the block on two pins and whacked the sides down, made the part .625 wide. Then I worked my way around with a .250 pin. Quick swiped on some paper on the granite table, and she came out good to less than a thou. That's a reflection of the chamfer on the radius gauge, there's zero daylight. Took about 15 minutes including grabbing a drill and some paper.

[u/[deleted]]

good in a pinch if your tolerances are huge, but anything precise and there is no way I would doing that

[u/maxar5843]

I was also thinking that a "cheap" digital readout could achieve the same thing as well. A lot have programming for a radius.