O-ring groove tool: Make or buy?

[Walt]

I need to cut an o-ring groove. It will be a static seal on a flat surface in aluminum 6000 series, 13/16" nominal diameter. This will be cut in a milling machine, and it seems like using boring head I already own is a good way to go. Mine uses 0.5" diameter boring bars. Yes, I know you can do the job in seconds on a lathe, but I don't have an operational lathe right now.

MSC sells an o-ring grooving tool with a 0.5" round shank, but it's ~$55 because it's made from carbide. Overkill for my requirements, but I haven't been able to find anything cheaper.

It looks like this should be a pretty easy tool to grind. The Parker reference gives a huge tolerance for the groove size. The shape is very simple. I need to make a groove somewhere in the 0.080" to 0.107" range (depends partially on whether it's to seal against air or water.)

I had a bit of stainless steel rod available and tried making a grooving tool out of it. It didn't cut extremely well, but I expected to have to try several times on scrap to get it right. But the stainless must be too soft, because the cutting edge dulls very quickly. Too fast to get anything useful done.

I have been reading posts on this site about heat treating, and I doubt that I can do a reasonable job. The Enco website lists W1 drill rod as possibly hard enough for some jobs without hardening.

My question is, would I be better off just paying the money for a professionally made tool that will do the job right, or can I get enough cutting life from some kind of steel (that I don't need to harden) I can grind on a bench top grinder with aluminum oxide wheels? This is for hobby/entertainment purposes only, I'm making some bike lights for myself and have no paying customers at this point.

Walt

 

[John Hasler]

I need to cut an o-ring groove. It will be a static seal on a flat surface in aluminum 6000 series, 13/16" nominal diameter. This will be cut in a milling machine, and it seems like using boring head I already own is a good way to go. Mine uses 0.5" diameter boring bars. Yes, I know you can do the job in seconds on a lathe, but I don't have an operational lathe right now.

MSC sells an o-ring grooving tool with a 0.5" round shank, but it's ~$55 because it's made from carbide. Overkill for my requirements, but I haven't been able to find anything cheaper.

It looks like this should be a pretty easy tool to grind. The Parker reference gives a huge tolerance for the groove size. The shape is very simple. I need to make a groove somewhere in the 0.080" to 0.107" range (depends partially on whether it's to seal against air or water.)

I had a bit of stainless steel rod available and tried making a grooving tool out of it. It didn't cut extremely well, but I expected to have to try several times on scrap to get it right. But the stainless must be too soft, because the cutting edge dulls very quickly. Too fast to get anything useful done.

I have been reading posts on this site about heat treating, and I doubt that I can do a reasonable job. The Enco website lists W1 drill rod as possibly hard enough for some jobs without hardening.

My question is, would I be better off just paying the money for a professionally made tool that will do the job right, or can I get enough cutting life from some kind of steel (that I don't need to harden) I can grind on a bench top grinder with aluminum oxide wheels? This is for hobby/entertainment purposes only, I'm making some bike lights for myself and have no paying customers at this point.

Walt

Make your tool out of a drill bit if you don't want to buy some high speed steel blanks to grind it out of.

 

[mekanix48]

I Walt
Do you have a parting off tool ? if so you can use that to cut an 'O' ring groove if you have enough clearance. You can make one yourself but it must be out of a 1/2"round section HSS tool steel as this will help with your clearances, you can grind it to size & fit your boring bar. Stainless won't work as it is soft initially then it work hardens as you use it & you will initially end up with a bent piece of metal in your boring bar/head & damage your boring head to boot, grind it as you would a parting tool tip or a trepanning tool & you should be fine, keep your speed reasonable & if you lubricate, use WD 40 or Kerosene mixed with oil. :victory:

Regards
George

 

[Dave Smith]

Walt---you can make your own flycutter or boring bar with carbide cutter ground to shape and size you need for cheap---look at thread --ideas for scroungers #36-----just cut off a blade section with a carbide tooth and mount it to the tool with small flathead cap screws you could also cut a slot in your tool and mount the part of the blade in slot with cap screws to firmly grip blade----many many uses for these inexpensive carbide tips from used blades----------------not even expensive to use a new blade for all the tips---I just use a very thin cutoff disk in my die grinder to cut the blade sections and to form them to the sizes I want for each tool--I drill the small holes first near the tooth to mount them with----you do need a diamond wheel to grind the tips to shapes you want-----Dave

 

[Flammable_Solid]

Use your rotary table and an endmill?

 

[Ulma Doctor]

get a common HSS pre-formed boring bar and grind the existing tip edge to fit the profile desired
like these

 

[Walt]

Thanks for all the great ideas!

I see now that Enco has 1/2"x6" HSS rod for $8, I didn't know it could be had for relatively cheap. That should be more than tough enough to cut aluminum.

I also have a trepanning tool, that could be made to work. I made an attempt last year to grind a grooving bit. My grinding skills are pretty poor, but the only way to get better is to keep trying.

No rotary table yet, or boring bars, or diamond grinding wheels, or parting tools in my inventory.

Much appreciated everyone. This hobby is expensive enough and I appreciate your help in keeping my expenses under control.

Walt

 

[kd4gij]

First I never buy somthing I can make even when it cost more to make:nuts:. You can grind a boring bar to shape.

 

[Terrywerm]

First I never buy somthing I can make even when it cost more to make:nuts:. You can grind a boring bar to shape.

Yeah, what he said!

I also prefer to make what I can, not because it saves me any money, but because it helps me learn and helps me hone my skills.

 

[FTlatheworks]

wrong thread