Grooved wheel

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Gordon

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How do you make a grooved wheel? I want to make a small tube bender to bend 3/16 to 5/16 tubing. This requires a radiused groove in a small wheel. In the past I have roughed out the groove and finished it with a file. I have also tried grinding a HS tool bit to the proper size but have not been too successful. Is there a better way to do this?
 

ShopShoe

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Gordon,

Do you have a mill and a rotary table? See the link below for an example of a milling cutter you might be able to use: These are available from most cutter vendors.


Otherwise, grinding a cutter for your lathe should be do-able. I have been able to do that in a similar situation.

Someone may have a grooving tool with the appropriate profile for use in the lathe as well. Sorry, I don't have a link...

--ShopShoe
 

stevehuckss396

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Well Gordon i'm not sure of the radius you need but there are many different sizes of round carbide inserts. If you find one that matches your needs it would be easy enough to make a shop made holder to get the job done.

Also you might be able to find a rat tail file with the correct diameter. Maybe use a parting blade to clear the bulk of the material out of the way and finish up with the file.
 

Gordon

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I have looked at the various mill cutters but at $50+ each is more than I want to spend to make one piece and if I want to make a set for various tube diameters I soon have some serious money involved. In the past I have roughed out the groove and finished it with a round file. I have also set them up in the rotary table in a vertical position and cut the groove with an end mill but even that requires hand finishing. I guess that I was looking for a magic solution but for limited operations I guess that my present method of hand finishing is the solution.
 

SmithDoor

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I have manufacturer thousands of Grove wheels.
The best found is plunge cut.
The cutter needs a high rake angle 10° to 20° or lathe will chatter.

Dave


How do you make a grooved wheel? I want to make a small tube bender to bend 3/16 to 5/16 tubing. This requires a radiused groove in a small wheel. In the past I have roughed out the groove and finished it with a file. I have also tried grinding a HS tool bit to the proper size but have not been too successful. Is there a better way to do this?
 

deverett

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I sort of remember John Bogs explaining how to do this.
Basically, in the milling machine hold your embryo disc on a horizontal axis in a rotary table/dividing head and using an end mill plunge down on the perimeter of the disc to the depth of groove. Rotating the disc cuts the groove. The cutting was done with the end teeth, not the flank.
There was a better explanation from JB but that was the general idea.
Dave
The Emerald Isle
 

SmithDoor

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Here photo of the wheels.
The big wheel is a 1,000 pound casting.
 

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Charles Lamont

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If you can buy round HSS tool bits in the size you want, you can make a tangential tool holder to hold the bit vertically and present the ground end face of the bit radially. A clearance angle as shown means the groove is very slightly elliptical, but not enought to matter for a tube bender.
 

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a41capt

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How do you make a grooved wheel? I want to make a small tube bender to bend 3/16 to 5/16 tubing. This requires a radiused groove in a small wheel. In the past I have roughed out the groove and finished it with a file. I have also tried grinding a HS tool bit to the proper size but have not been too successful. Is there a better way to do this?
Get a piece of drill rod in the diameter of the tubing, grind a relief angle on it, harden and temper, stone the edge, mount it in your lathe tool post, mount up the stock you intend to use as a die, and cut to depth. The drill rod tool doesn’t have to be long lived, and depending on your choice of material for the die (aluminum works great!), the tool will last as long as you need it for the project.
 

Mousetrap

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How do you make a grooved wheel? I want to make a small tube bender to bend 3/16 to 5/16 tubing. This requires a radiused groove in a small wheel. In the past I have roughed out the groove and finished it with a file. I have also tried grinding a HS tool bit to the proper size but have not been too successful. Is there a better way to do this?
 

BIGTREV

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How do you make a grooved wheel? I want to make a small tube bender to bend 3/16 to 5/16 tubing. This requires a radiused groove in a small wheel. In the past I have roughed out the groove and finished it with a file. I have also tried grinding a HS tool bit to the proper size but have not been too successful. Is there a better way to do this?
Is sort of thing you're thinking of making..
4 in 1 180° Handheld Small Pipe Bender Heavy Duty Tube Bending Tool 4/6/8/10 mm | eBay
 

stevehuckss396

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The problem with those benders is the radius of the bend is often much larger than what we need for our projects. I have one but still have 2 other benders for much tighter bends than the "stock" benders can offer.
 

Gordon

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I have that type of bender in two different sizes but they crush thin wall tube. I have a bender which I made when I built a Snow engine and it works much better. I want to make a bender for some other sizes and radii and making the grooved wheels for the Snow type bender was a lot of work so I was looking for a better way than rough out a groove and hand finishing it.
 

Ken I

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Gordon, Here's a link to a bender (and plans) I posted some time back - also milling the radius in the rollers.

Wire & Tube Bender

As mentioned you can use hardened drill blank (or the hardened portion of a busted drill behind the flutes) sharpened and used as a tangential turning tool.

Regards, Ken
 

terryd

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Well Gordon i'm not sure of the radius you need but there are many different sizes of round carbide inserts. If you find one that matches your needs it would be easy enough to make a shop made holder to get the job done.

Also you might be able to find a rat tail file with the correct diameter. Maybe use a parting blade to clear the bulk of the material out of the way and finish up with the file.
Hi Gordon

I made mine by using ball ended milling cutters of various sizes using my milling machine and a rotary table. The disc for the wheel was mounted vertically below the cutter and several incremental cutsa were taken until I reached the required depth. As this was a one off situation I opted for cheap carbide cutters from China via eBay. They were good value and quite successful and are still in good condition. My formers were made from aluminium discs with a brass bush. You don't need anything fancier.
I did a partial thread about my own tube bender which is based on one from 'Model Engineer', It is veratile and was enjoyable to build. It's here and can handle tube from 2mm od up to 8mm od a suitable range formost models.


TerryD
 

JohnBDownunder

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Gordon, if you have a 3D printer here is a link to the one I made from Thingyverse.
There is also a video of it being used by MyfordBoy.

I varied the dimensions to suit the tubing and bend radius plus made the arms a bit longer = easier to hold.

For small tubes they worked fine for me. There are others on Thingyverse but it is a challenging search.
Matching the radius of the half circles to equal the diameter of tube helps a lot in preventing crushing.
 
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rklopp

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For small bender grooves, say up to 1/8" radius, I use a commercial radiused carbide grooving tool from Nikcole and trig out the cuts. I have a DRO on my lathe, so that helps. I use a spreadsheet to calculate the cuts at equal angle increments, say 5°. By using equal angle increments, the leftover cusps in the surface are equally spaced and easy to polish out if necessary. Incrementing by 5° means 36 cuts for a 180° groove. The raw coordinates are based on the center of the tool radius. For example, the Z (axial coordinate) for a cut is the groove radius minus the tool nose radius times the cosine of the angle and the raw R (radius coordinate) is the groove radius minus the tool nose radius times the sine of the angle. The radial (X) coordinates are transformed to DRO diameter readings by subtracting from the work radius and multiplying by two. I print the spreadsheet and step through it using the DRO. I have done this without a DRO, but it is not easy and I have to watch backlash. I used a long-travel dial indicator for Z.
 

Master

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Needed intake and exhaust pipes on my 5 cylinder aircraft engine. Intake needed two bends, exhaust only one. Ground a bit with radius for 9/32 tubing. Made two grooved wheels in aluminum. One wheel was mounted stationary. The other was movable to make the bend. Melted cerrobend into the tubes. Made my bends then melted the cerrobend back out for the next tube. Each one came out perfect. No crimping or collapsing of the tubes.
 

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