Milling machine and mag drill cutters

[whichwire]

Hello,

new to this forum but need some advice. A few years ago we came across a bridgeport milling machine for a few hundred quid and its been our main drilling machine since.

Last we we got some tooling which allowed use to use standard magdrill cutters in a quick change tool and this opened up all sorts of possiblites, its be drilling holes almost constantly since.

Lately I been trying to make slotted holes in 50mm box section (both sides) and we were talking to supplies about slot drills etc but I wonder whether with a good quality long series mag drill cutter, could it be used to create slots once the initial holes has been made?

thanks

 

[brightspark]

try cutting one side 1st slow feed then follow on through second side if there is no chatter whilst cutting should b ok. but why cant u just use short cutters and turn the box section over in vice it would be setup for second cut surely

 

[wyn]

I wouldn't have thought the mag drill cutters would be able to handle the side ways loading the same as a slot drill. They'll probably just shatter into bits. The only way with a mag drill cutter would be a series of linked/overlaping holes..but then that wouldn't be a smooth slot. It should be an easy job with the right length slot drill.

 

[astro_al]

Brightspark, I think he's talking about cutting with the side of the cutter (moving the table of the mill sideways once the tube has been drilled into).

Cheers, Al.

 

[brightspark]

best thing would be buy a clarkson autolock collet chuck and use slot drill theres plenty about on e bay depending on the taper .either 30 or 40 international or r 8 my brigeport universal is 40 int

 

[snowcat]

you can plunge in the side of a hole with a broach cutter, but not slot drill.... ie sideways as said a Colet chuck and some end mills are the way to go, cheaper also once the chucks bought....

 

[hareng]

Forget the collet chucks biggest pile of junk ever developed inc ER, Clarkson etc. Take an eternity to change cutter even longer for a different size collet.
Have to use them at work.

Go for the R8 taper collets, may be known as finger collets, grip well and the quickest to change a cutter over 5 to 10 secs! Dont lose any height either same with MT2 and MT3 collets, further more theres no added error introduced and the lateral play is closer to the spindle bearing often leading to less breakages, scrapping and better finish due to wear.
You will also find you can put a cut on as well.

 

[brightspark]

when the cutters collets and chuck come your way for next to nothing and used on a part time basis what would u choose

 

[hareng]

I would rather go without and use a file.
The cost in cutter breakages and abnormal wear in a month could buy collet set, not exactly expensive!
Me i want the job done right, accurate and quick with no faffing about.

 

[brightspark]

so does that mean at work u dont do the job right end of story

 

[HasBean]

Broaching cutters can't (really) be used for sideways cutting, they're not designed for it, like cutting a slot with the side of a drill bit, anyhow slot drills are generally cheaper anyway?

Split collets holding the cutter and closed by drawbar are a good option, cheap and little overhang, but cutters do tend to get drawn out under heavy use. Where the threaded shank cutters in a clarkson type chuck works best (for me anyway) is in profiling as the cutting action tightens the cutter into the chuck stopping it being drawn out.
I use threaded collet chucks, ER chucks & split collets, they all have their uses.
Horses for courses at the end of the day

Paul

 

[whichwire]

thanks for info.

We been using mag drill cutters all week so far, the slot is 2 hole widths so we're drilling 2 holes then connecting them with cutter. Its a 24mm dia slot. Its only ok. Have a 22mm slot drill with turned down shank to fit into 20mm ER collet. We see if this improves things!

 

[Weldingartisan]

Forget the collet chucks biggest pile of junk ever developed inc ER, Clarkson etc. Take an eternity to change cutter even longer for a different size collet.
Have to use them at work.

Go for the R8 taper collets, may be known as finger collets, grip well and the quickest to change a cutter over 5 to 10 secs! Dont lose any height either same with MT2 and MT3 collets, further more theres no added error introduced and the lateral play is closer to the spindle bearing often leading to less breakages, scrapping and better finish due to wear.
You will also find you can put a cut on as well.

Couldn't agree more, I've got a Clarkson type holder almost brand new unused, never had a R8 collet slip. The only adapter chuck I use is an ER40 to get 25mm holding capacity. What is the point of using an unnecessary adapter? It can only increase run out and chatter. W/A

Sorry, forgot the thread there. For a large slot, two holes with the broach cutter and a slot drill or end mill down the sides.

 

[brightspark]

hmmmmmmmmmmm milled sum half inch slots in my pedestal drill table 2day took bonus cuts. didnt chatter must be doing sumthing rite

 

[Weldingartisan]

hmmmmmmmmmmm milled sum half inch slots in my pedestal drill table 2day took bonus cuts. didnt chatter must be doing sumthing rite

But why would you use another adapter when the R8 collets are more than fit for purpose? You can't deny that increasing the length from headstock to workpiece must increase the risk of run out and chatter. W/A

 

[chap]

I always though that you use screw shank cutters in quick change systems for repeat production work.

We tend to use R8 in the bridgeprt type m/c's and ER in the CNC machining centre, though the ER collets are generally for holding drills.

More on topic, with the broaching cutter, can't you overlap the drilled holes? I thought that was the whole point of broaching cutters; that they are so rigid? this would give the milling pass an easier ride, with less meat to remove.

 

[hareng]

The Clarkson use threaded milling cutters with a central pointindent which have to be set just right before tightening up that monstrous clampy thing.

ER and ****** dont have indents, can use straight or threaded same as with MT or R8 collets.

 

[Weldingartisan]

Well yes, if you are doing production runs on a regular basis an indexing tool holder system would be worthwhile. But for Joe average doing occasional machining (like me and many on this forum) they are an expensive/unnecessary addition. W/A

 

[Pete.]

The best thing to do would be to buy two R8 blanks and make a R8 holder for the 24mm annular cutter and another to hold a 24mm slot drill. Now you have two tools that will swap-over quickly with a tap of the drawbar, won't chatter, have little overhang and the cutter won't pull out and gouge your bed.

Set up your table stops. Pile the annular cutter in, switch to a slot drill, run the table up to the stop to make the slot, switch to annular cutter, change the workpiece, cutter in, slot drill, run other way, etc etc etc

 

[Weldingartisan]

Not a bad idea, but besides the cost of blanks, machining and a 24mm slot drill - thats a lot of meat to remove on a Bridgeport. I would set the stops and run a 10 or 12 slot drill down each side to join up the holes. W/A