Annular cutter

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Larry$

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I've been considering these (annular cutters.)
But have zero experience with them. I see they typically come with a guide pin. 1. Is it necessary if using a mill or lathe?
2. How do you get the slug out of the cutter?
3. The plan was to buy an MT3 adapter to use the lathe and just use 3/4" collet on the mill. OK?
First use is a series of 2" holes in 1/2" mild steel on the mill.
4. Do you use power down on the mill? Do you have to retract/peck often?
5. My mill & lathe are both 3 hp, I'm assuming that is enough for 2" diameter in steel.
6. For hobby use are the Chinese sets OK?
7. I plan to use cutting oil.

Thanks
 
1) the guide pin isn't needed to guide the cutter, if that's what you mean. They're primarily to line up on a centre punch and spring loaded (2) to assist pushing the slug out.
Pass on 3.
4) on deep cuts you may want to peck occasionally. Depends on chip clearance (see answer 7) I like power feed so long as you're happy you've got a speed that suits the cutter.
5) I think that should be plenty. There are some online cut HP calculators that will help you clarify. Treat as single point lathe tool, DOC the width of the cutting edges, feed to suit, and multiply by no. of flutes.
6) probably a bit of a lottery. I'd go economy name brand on a job like this.
7) I'd go with soluble coolant and an acid brush or mist. Flood if you have. Less gumption to hold chips and more heat removal.

HTH :)

I've got 800 rivets (well, stays, technically) to drill out of a boiler with a mag drill and small annular cutters in the near future. Not looking forward to it! Lol
 
Lo-Fi said:
1) the guide pin isn't needed to guide the cutter, if that's what you mean. They're primarily to line up on a centre punch and spring loaded (2) to assist pushing the slug out.
Pass on 3.
4) on deep cuts you may want to peck occasionally. Depends on chip clearance (see answer 7) I like power feed so long as you're happy you've got a speed that suits the cutter.
5) I think that should be plenty. There are some online cut HP calculators that will help you clarify. Treat as single point lathe tool, DOC the width of the cutting edges, feed to suit, and multiply by no. of flutes.
6) probably a bit of a lottery. I'd go economy name brand on a job like this.
7) I'd go with soluble coolant and an acid brush or mist. Flood if you have. Less gumption to hold chips and more heat removal.

HTH :)

I've got 800 rivets (well, stays, technically) to drill out of a boiler with a mag drill and small annular cutters in the near future. Not looking forward to it! Lol
Click to expand...

What size rivets? The smallest annular cutters with Weldon shank are prob 7/8" (or)?

Or are you using sheet metal type annular cutters with a jacobs type chuck in your mag drill?


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I have a Hougen 130 mag drill and cutters from 7/16” up to 1 1/2”. They have a locking system on top that fits the drill only. With that being said, I have used them in a collet, and went easy on them and had good results. The cutters need a decent amount of down pressure to cut correctly, and when you have it right you will know it. I release the pressure when the chips get about 2” long to keep them from bird nesting on the cutter. Now, I also have cutters with 3/4” Weldon and a R8 to Weldon adapter for the cutters I got to use on the mill. They work great, and you don’t have to worry about slippage. If I didn’t already have the mag drill, I wouldn’t be using the roto-lock cutters in a collet.
 
9/16 up to about 7/8, @lis2323 . I found some small Weldon shank cutters from 13mm up, which are rather handy.
 
I've been considering a set. They do seem handy.
 
If material thickness is less than 3/8” then Rota Broach (or other branding) cutters will work well in a regular drill press.


73df839f0c42cc148d9c01f26f3117bb.jpg



Annular cutters with the 3/4” Weldon shanks I use in a mag drill, with a 3/4” collet in the Bport clone, or with a MT3 - 3/4” Weldon adapter in the drill press

cb52750229e967cd0a936598d00af8f5.jpg



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I have annular cutters from 5/8" through 1 5/8" with a 2" cutting depth. Also the Roto-Kut set from Kimball, the latter is only for thin gauge materials, often use it for electrical cabinet work. Both should be used with constant pressure, lube when possible and require rigidity in the cutter system, do not tilt, peck or force the cutters.

1. Guide pin is not used on the mill or lathe, at least I haven't used them.

2. Slug usually just falls out

3. I use a MT3 adapter on the lathe and use to use a just use 3/4" collet on the mill which works fine. I subsequently purchased a 3/4" end mill holder and drilled/tapped two holes for Allen screws to secure the cutter. The end mill holder is case hardened, so a bit hard on the drill.

I drill up to 2" deep with a 1 1/4" annular cutter and have cut numerous holes in 1/2 steel plate.

4. I generally do not use the power downfeed, but use constant pressure. If I had a lot of holes to drill then I would use the down feed, it is just the rate of speed will vary based on the annular cutter design, size of hole and diameter. You do not need to apply high pressure, you want continuous material removal. Do NOT hunt and peck, they are made for continuous material removal. On a deep hole I will occasionally back the cutter out to break the swarf, blow out any chips and apply cutting oil. Also annular cutters must be used with much lower RPM then drilling. I was told to keep the maximum RPM under 400 RPM for cutters in the 5/8-3/4" and lower for larger diameter, it is somewhat material dependent, aluminum one can go higher. One reason is the swarfs are cut in ribbons so they need to clear from the cutter.

RotaCut and Holcuter Suggest RPM Speeds Chart

Starting RPM speed rates for RotaCut and Holcutters.
www.hougen.com

5. My mill & lathe are both 3 hp, I'm assuming that is enough for 2" diameter in steel.
My mill and lathe are 3 Hp, have used them up to 1 1/2", but see no limitation with larger annular cutters. Depending on the material I would use a speed of 200 RPM in mild steel with a 2" cutter.

6. For hobby use are the Chinese sets OK? You get what you pay for, so it is hard to judge the quality and how well they will perform. If you are doing a lot of holes in a particular size, buy single cutters on eBay of a more mainstream brand.

7. I always use some form of cutting oil or lubrication with the annular cutters, it will cut smoother and not bind. You should be getting single long ribbons of swarf, be very careful with the hands around that stuff.

20180619_184219.jpg
 
I have the Blair Roto-Broach in 5/16" thru 1-1/2", and have been very happy with them. I mainly use them in a hand drill with cutting oil, but have used them on the BP in an R8 collet. Very handy tool to have in the arsenal, and leaves a much cleaner hole, and cuts faster than a hole saw. I can see for a 2" hole that flood coolant would be the best approach if available. Mike
 
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