Halco milling head

Hi all,

I have been going through the EE Garvin #4 that I picked up from Irby a few years back. The restoration is coming along nicely and I am looking for some tooling. He gave me a Halco model B-5 milling head for it as well and from what I can find online this should be a BS#7 taper. When I measure the front of the taper I get approx 1.05. That’s closer to a #9. I was wondering if anyone has one of these that might know for sure. I suppose it’s possible that someone modified it but it doesn’t look like it. I was surprised how little I have found on these.

Thanks Nathan

1.05" is very close to a B & S No. 9 taper. Too large for a No. 3 Morse and too small for a No. 4 Morse. Get you a No. 9 taper shank-sloid and blue it to the bore of the spindle and see how close it mates with the tapered shank. I bet it will be right on. These older milling attachments were common to be equipped with B & S tapers. Ken

Thanks Ken

I suspected as much but I also wasn’t sure what else there might be out there that I haven’t heard of. I’ll hunt one down and order it

My Halco is a model Z and is a B&S 7. It wouldn't leave much meat at the end of the spindle if it was a 9! Would love to see a pic of yours!

The project is coming along. I’ve been pouring every free minute into it since I need a mill for a few other projects. The Halco will really expand the versatility of the mill. I’m eyeing some BS9 tooling on eBay so I can test it out. I hope to have the main spindle and the feed pulleys cleaned up and back in over the next few weeks

Way Cool! I wish someone can blow the pics up to a viewable size LOL. We should start a thread together "Calling all Halco owners." I know they ARE a pretty simple unit but there was changes over the years and I'm sure people adapted them in different ways to existing mills. For example, I'm making a new overarm for a Victoria U2 and while my head won't nod, it will tilt. Keep us posted, as there isn't a lot of writeups on these little guys.

I have all the high res pics but sometimes they don’t upload right. I’ll try here

From the thumbnails that head looks identical to the Halco I had on my first mill ~15 years ago. I advise fabricating a cover (could be anything; wood, metal or even cardboard) to close out the top of the belt guard to keep fingers out. In the highest speed the belt can be reached by a misplaced finger, ask me how I know.

My head was B&S #7. You can purchase both B&S #7 and B&S#9 collets new from littlemachineshop: Collets and Chucks: Brown & Sharpe Collets - LittleMachineShop.com

Enjoy the machine. I made plenty of good parts using my head before moving up to a bridgeport.

Sometimes if you resize the photos smaller (like 1280x960 or 1024x768 max resolution) before uploading, they'll show larger. The forum automatically compresses photos over a certain size.

DeSelle said:

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I have all the high res pics but sometimes they don’t upload right. I’ll try here

Click to expand...

1.05" is easily 25% larger than MT #2.

On-Edit:

But is isn't big ENOUGH to fully seat a B&S #9.

As one would HAVE to do for the way B&S collets work.

So I think you have a B&S #7.

Order yerself ONE of something in <correcting> # 7 B&S to check the spindle with.

Nathan, I thought I gave you the Halco head that had a Morse taper #2 in it. I know good and well it's not a B&S #9 because I have that in my Millrite and it's way too big for a Halco. See if you have or can find an MT #2 to try in it. The Halco's usually had a B&S #7 and I have another one here with that taper. I used that head some here and I'll go find the cutters I used and see what they are for sure. Heck, didn't I give you some cutters?

Irby

EDIT: One second thought - doesn't that head have something on it that says the taper? Seems I saw something on it that told me the taper. Somehow I knew it wasn't B&S #7 but MT #2.

Nathan

Check the threads on the draw bar. The B&S #9 collet takes a 1/2-13 thread. The B&S #7 and the #2 Morse collet both take a 3/8-16 thread.

The end diameter of the B&S #7 would only be 0.709" and the MT #2 would only be 0.730".

Irby

I’ll have to see if I can look into this taper a little more. The drawbar is 1/2-20 which doesn’t match the BS9 or the BS7 or anything else I know of

Well I mis measured the opening but now I am more lost on this one. The opening at the front is .920-.930. I stuck a MT#2 drill chuck in it and it hangs out per the pic. Then I blued up a new MT3 adapter and stuck it in. It sticks out about 1”. I measured the spot where the blueing rubbed off at the front and it measured about the same at .925. I confirmed the drawbar to be 1/2-20. Looking into the taper it appears straight and there is a shoulder at 4.300” deep where the diameter reduces for the drawbar.

One more question about tapers.....

When they say big end diameter it that the diameter where it exits the bore or the diameter at the extremity of the taper?

DeSelle said:

One more question about tapers.....

When they say big end diameter it that the diameter where it exits the bore or the diameter at the extremity of the taper?

Click to expand...

Same as beef for burgers when planning a cookout.

Taper is ordinarily sold by the pound.

Then you tell the butcher how you want it ground.

Less confusing that way.

I would assume there is a theoretical gauge line Bill

DeSelle said:

I would assume there is a theoretical gauge line Bill

Click to expand...

Indeed. But "to date"? "make an ass of u and me" is the operative version of "assume".

One does HAVE to wonder:

- How your measurements at the opening could be so dramatically different?

- How you could physically insert a genuine MT # 2 and then a physical MT # 3 ..and not notice if one, the other, both, or neither actually took a "seat" in the taper?

They aren't JUST different sizes. The taper ANGLE is actually a skosh different, too. B & S tapers have a similar erratic variation built-in.

Oscar Beale wasn't a homeless vagabond. He was a notoriously EFFECTIVE overall Works Manager AT B&S ...when he developed his "jarno" taper to REMOVE such vagrancies and build the measuring and taper calculation right INTO the very number itself, all jarno the same angle exactly.

And then..

- How you could describe the bore as straight-sided cylindrical?

Could we just "start OVER?"

ALL the possible tables are here:

Machine taper - Wikipedia

All the evidence (Irby's recall at the head of the list...) says you have a HIGH probability it is #2 MT.

A lower probability it is #7 B&S. No genuine "third choice".. that we know of.

Check for internal burrs.

- See if the MT #2 SEATS.

- Try more than one if you have more than one.

If none handy? Buy brand-NEW, even if El Cheapo, MT adapter sleeves.
Seldom useless. And the cheapest way to equip yourself with what can also serve as gauge plugs AND gauge sockets. Not many needed to go from # 1 MT to # 5 MT. No longer a need for tedious measuring.

And soon off to DO stuff, rather than ponder over a mystery that is probably NOT a mystery after all?

"P.S." If the drawbar thread is ODD? So what? It simply becomes a "bystander" for now. Just "aside it". Allow it to confuse us NOT.

Once you have a source for collets, side-locks, "whatever"?

Make a drawbar to fit what you actually HAVE.

Not as if a drawbar were a nuclear reactor.

DeSelle said:

One more question about tapers.....

When they say big end diameter it that the diameter where it exits the bore or the diameter at the extremity of the taper?

Click to expand...

If you go by what the Machinery's Handbook says, The big end at the face of the nose of the spindle, that would be the "gage line" for a Morse taper socket. When you blued the no. 3 MT shank and wrung it into the bore of the spindle, did it mate for the full length of the shank of the taper? Or just touched at the gage line? IT sounds like you have a no. 3 Morse taper in the spindle even though the gage line is undersize by 0.008". According to the Machinery's Handbook, the diameter at the gage line should be 0.938". Machine builders don't always follow this and probably put a tolerance of 0.938" +0, -0.010", so that way if for some reason in life, you have room to regrind the taper.

As for the the odd draw bar thread, that mill head probably started out using tanged shanks, quickly changed to a draw bar with some kind of thread on it. Back then, there was and still today, no standard on draw bar threads for Morse taper shanks. So everybody pretty much did their own thing. That's the reason for the 1/2-20 threaded end. OF course over the years, tooling makers started establishing their own standard on threaded shanks. That the reason for finding no. 3 MT shanks with a common thread of 1/2-13 or the metric thread, I believe is M12.

What I would do is make a new draw bar with 1/2-13 threaded end so that way it will work with most shanks available today.

Ken

This is more a curiosity at this point. My memory of the MT 2 was off apparently since the MT 3 fits in there well. It was back in 2007 and 2008 when I was playing around with that milling head so my memory is off. I wouldn't have had an MT 2 collet around anyway to use, so it had to have been an MT 3 collet I used. I had them around for a lathe I had then. But the drawbar threads are still a mystery. I had another Halco head that uses B&S #7 collets and I may have well swapped drawbars with that head since it has a 3/8-16 threaded drawbar.

As to the length issue, I think everything is OK. The large diameter of an MT3 taper is 0.938", and an MT 3 collet will stick out some so the 0.925" Nathan measures seems OK to me. The length of the MT 3 taper is 3.19", so it would fit into the 4.300" depth he measures also.

Irby