BCA jig borer

Hi

carbide endmills are only available in metric (I believe). My BCA jig borer only accepts imperial. I believe that there may be an imperial/metric adaptor, but I don’t know how it is used or what it looks like.

can any one help me get set up with endmills using carbide?

regards

john

Have a look at someone like MSC Direct (uk) as their parent company is US based they do stock imperial sizes in carbide

John

Another UK supplier is Drill Services at **LINK**

Plenty of choice of type and inch sizes.

Emgee

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There was a metric version of the special collet for ‘screwed shank’ mills … With hindsight, I wish I had bought one when they were available [but they were pricey, so I only bought Imperial]

As screwed shanks are no-longer popular … Your best bet would probably be to make [adapt] an ER Collet holder.

MichaelG.

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Edit: __ You may find this useful : 

https://www.modelenginemaker.com/index.php?topic=8048.0

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Edit: __ or maybe not [the embedded links are dead] 

Edited By Michael Gilligan on 15/03/2022 14:29:19

I would caution that the BCA collets don't grip as well as some other systems. There's a very strong chance of a carbide endmill pulling out of the collet.

I've been wondering about making a BCA side lock holder for FC3 disposable cutters. They have the advantage that they can't pull out due to being retained by a grub screw in the Weldon/sidelock slot in the cutter. They're also available in carbide.

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Agreed … that’s why I mentioned the special Crawford collets that they supplied for use with screwed-shank cutters

But as Carbide end-mills are not generally available with screwed-shanks, other options need to be explored.

MichaelG.

Do you think that an Osborn chuck would hold an unthreaded endmill? If so what modification would be necessary?

Not really knowing the BCA's spindle would it be possible to get a plain shank ER16 chuck and turn and thread the shank to the shape of a BCA collet, you would probably loose 25mm of head height doing that.

EDIT, looks like others have done similar here

Or what about turning and threading some steel again to the profile of their collets and then reaming to take your chosen cutter dia and cross drilling for a grub screw to make it like a sidelock holder but one that will fit right up into the spindle.

Edited By JasonB on 15/03/2022 17:13:03

RDG tools did supply BCA adaptors with blank ends, several of which I purchased for mounting slitting saws and one adapted I made into an ER16 collet holder. Unfortunately RDG only appear to now stock adaptors with a threaded nose.

I have an ER16 adaptor that I think fits an EMCO lathe threaded spindle which is 14mm x 1mm. If used with an RDG adaptor it would reduce headroom by 50 mm .

Having a new spindle made for the BCA with a ER16/20 nose, although not trivial, would solve the problem of cutter holding and headroom. If I remember correctly the BCA spindle is of relatively simple design.

Clive S

I have the internally threaded collets for for both metric and imperial, and to be honest I find HSS screwed shank cutters are more than adequate for anything I need to do on that machine.
Mine is a Boley and Leinen which is the predecessor to the BCA mk2 and uses the same collets.

These machines are not made for hogging lots of metal off, and I have never felt the need to use carbide cutters on mine, I do use them on my Alexander milling machine when I need to shift a lot of metal quickly.

I would be thinking about the spindle and its bearings and whether you think they are up to the forces required to get the best out of carbide cutters. The BCA is a jig borer, and as such was designed for precision positioning of holes as opposed to true milling operations. Milling is OK but not really when you are trying to take heavy cuts. Also with carbide you would probably want to be running the spindle at a far greater speed than the machine will be happy with.

As mentioned above, the internally threaded collets are like hens teeth, it took me about three years to get my set complete, but they do "almost" guarantee that a cutter will not walk out of the collet.

Have a look here at some of the additional tolling I have made for mine.
https://www.model-engineer.co.uk/albums/member_album.asp?a=35949

Phil

Are carbide end mills available with screwed shanks, never seen one. From experience screwed shank 6mm and 1/4 inch cutters for autolocks usually break out at the center end.

You can probably use plain shank cutters in a Crawford collet. I have used them in a Clarkson autolock holder by putting a washer behind the collet to close it.

If you can get away with a 3mm end mill, I used to use engraving cutters in a 3mm collet but you can sleeve them down from 6 to 3mm easily. I used to buy mine on EBay but that was around 10 years ago. I expect they are still available.

Following on from Clive’s post … This would make a good base for adaptation : **LINK**

https://www.ebay.co.uk/itm/371542545425

MichaelG.

Carbide end mills readily available on EBay. Both 3mm, 4mm and also 1/8th. About £5 each.

Also the 30 and 60 degree engraving cutters make excellent centre drills, I used them on angled faces to start off a drill with no problems.

Thank you everyone for your comments, which have given to me me plenty to go on.

John

I'm not sure if this will help, or not, but I had a similar predicament when tooling up my 3D router. The router spindle as standard took 1/4 inch cutters and I wanted to use metric ones. I bought a couple of reducers intended for Trend routers. One was 1/4 inch to 4mm, the other was 8mm to 6mm. The latter fitted into a replacement 8mm collet. The web site suggests that the reducers are a stop gap solution and warn against prolonged use. My experience shows that they can be used for extended periods of up to 10 minutes continuous use, running at up to 12,000 rpm. I get the impression that the OP would be using his cutters for shorter durations and at much lower speeds.

John

PS If you choose to go this route, be warned, they aren't cheap. I think I paid about £18 each, but they did the job.