Tapered Pins

.. of course I can make my own but for a one off project, but for a repeat stock job I would like to buy them premade.

I'm cutting a mold for somebody that casts a body with a through hole. There are nominal dimensions, but a tapered pin that knocks out easily would be acceptable. I can buy "standard" tapered pins and "standard" tapered reamers, but when I was trying to spec it out it seems the pins are available in sizes ranging down much smaller than the small end of the reamer. Or in other words, "WHAT?!?"

I went ahead and bought a couple sizes of pins that would be suitable for the casting, and a 0-10 set of tapered reamers. I don't know how its going to work out, but I figure if worse comes to worse maybe I can make a tapered D-Bit reamer that actually matches the pins.

Bob La Londe

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South Bend used taper pins on my lathe, some of which didn't survive the students' abuse. I acquired some spare parts which had been drilled differently for the taper pins. It seemed to me the idea was to ream by hand, tap in the pin and then cut off the excess.

"Jim Wilkins" snipped-for-privacy@gmail.com on Fri, 19 Jul 2024 20:46:02

-0400 typed in rec.crafts.metalworking the following:

I still have a batch of brass taper pins made for the class machines. Brass shears off and protects the machine - at leas that is the theory

The thing is there really isn't any point to having stock size taper pins available more than minimally longer than you can ream. I was excited to see a couple pins available that might fit my application only to find I would have to create my own tool to ream the holes. I can make my own tools, but it takes a lot of time.

I'm an idiot. Since the taper is the same 1:50 for inch tapers and 1:48 for metric tapers of all "standard" taper pins I can just use an "off" size reamer to finish out the hole. Doh!

I know that feeling. Is what it would cost more or less than what I would spend making one? And how soon do I need 'it'?

-- pyotr filipivich "With Age comes Wisdom. Although far too often, Age travels alone."

---------------------------------------- I may make something once to see if I can, and perhaps note what I could buy to help. A 6" drill press vise is on the list to consider, to hold sheet metal panels to drill or mill. My mill's old Wilton vise holds 4", 5" without the hardened jaws.

Right now there is a 20' long, originally 4500 Lb log on my sawmill, nearly ready to saw off the 4th slab. I know now that I can do it but don't plan on another. Much of my equipment needed upgrades to handle it.

I have 4 drill presses. Maybe 5 if you count the little mill/drill. I rarely use any them anymore. Most drilling gets done with one of the CNC Mills followed probably by a hand held drill motor these days. I very rarely finish a tapped hole with a tapping head. However, do use the floor drill press once in a while. Sometimes its just the fastest and easiest way to waller out a hole in something. I've got a few drill press vises, but tended to use a "CNC" mill vise more often as its much heavier, and can be squared up on the table in any orientation.

A couple Christmas holidays ago my son and I made a slide lock drill press vise and gave it to my dad for Christmas. As far as I know he never used it. I did put it on his drill press once when I was out that way, but there is no sign he ever used it. When I started cleaning out his shop I brought it home and put it on my floor stand drill press. Once you get a feel for how to use it (wish it had a faster screw) its a pretty amazing device. I haven't used any other vise on that drill press since. I machined two grooves and a step in the jaws. So far it has worked for most everything I've drilled on that machine.

All of that being said for manual drilling I use the knee mill much more often than I use a drill press. I might use it more if I put a slide lock drill press vise on it too. LOL.

One thing I would change is to set the bars and screw in the middle of the split clamp instead of above center.

I have it set so it angles down towards the jaws slightly so when the split clamp is tighten the bottom of the jaws put slight pressure on the table.

Often when finding a hole with a punch mark, I'll put the drill in the punch mark, and then tighten the split clamp.

Right now there is a 20' long, originally 4500 Lb log on my sawmill, nearly ready to saw off the 4th slab. I know now that I can do it but don't plan on another. Much of my equipment needed upgrades to handle it.

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This evening a wild rabbit watched me working on it from about 10' away.

I'm an idiot. Since the taper is the same 1:50 for inch tapers and 1:48 for metric tapers of all "standard" taper pins I can just use an "off" size reamer to finish out the hole. Doh!

-- Bob La Londe

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I didn't suggest following with a second smaller reamer because I couldn't think of a way to ensure it aligned with the first radially and axially, the necessary extended shank could let it wander and there's no easy way to know when to stop. I'd ream to position the large head of the pin relative to the surface, cut off the small end and bin it for later. For a small pin in a deep hole I'd use a dowel or roll pin instead.

Hammerlock chain links have another way to retain a pin. It's turned smaller in the center and passes through a nested pair of large split roll pins with their slots opposed. They expand to let the end pass, then shrink onto the smaller center. Unlike shackles one end is no larger than the bow and fits into chain links. The pin is fairly easy to hammer or squeeze in and punch out.

The drill press vise would be for the mill, to hold large but light material, mainly sheet metal for electronic control panels etc, plus give more badly needed working space under the spindle for upright jobs like 5C collet blocks. My Clausing 8525 mill is the early version without the column riser block. I had to remove the hard jaws to clamp 6 squares of 5" wide 14 ga steel for a hole saw, and wider steel would have been better for hoist baseplates. At Unitrode I replaced a worn-out drill press with an RF-31 mill drill and bought an 18 lb 6" drill press vise for it instead of a 70+ lb milling vise that could crush a foot. Machine work for electronics is mainly on aluminum sheet and light extrusions, and no one wears steel toe boots.

Milling machine does a fair job with alignment as long as you don't move anything. The reamer will follow the existing hole.

There is a saying, "Drill fast, bore straight, ream to size." Somebody else must have said it first, but I've never heard anybody else say it exactly that way. For now I am the guy who said that saying until somebody tells me different.

It's a mold so depth is easy to find. Just open the mold and look. The pin slot was already 3D machined fairly accurately. 0+ to -.001 or better anywhere along the slot. The reamer(s) just needs to kiss the hole to make it a smidgen smoother. Its a lead casting mold so as long as the pin sets at "about" the right position castings will come out fine. You don't get flashing with upto .004-005 gaps unless the mold and lead are overheated. I vent .0015 to .003 every day without issues on gravity casting lead molds. (Resins and injection have their own set of issues and tolerances.)

I have already tested fit without reamer cleanup and it "would work" as is. I'd just like it to set set a little deeper for ease of dropping in the pin. I think just kissing off the machine marks from the original

I'd ream to position the large head of

A straight pin would work, but the customer wants a taper pin because it will theoretically knock out easier. It will. With a straight pin you have to DRAG the pin out of the casting for the entire length. With a taper pin a light tap with a soft face hammer and it just falls out.

I may not have done an adequate job of describing the application. The taper pin is not for "joining" or "aligning." Its to be used as a removable core.

FYI: I make similar casting molds all the time with straight pin cores, and they work just fine. They do require more effort to remove, but they work just fine. In this case its a custom mold, the customer has no experience with lead casting, and they are a bit OCD. Its easier to charge them for the work than to argue with them and it needlessly burns less of my time.

Similar mold I make with straight pins larger and longer than the custom mold above.

Did you look a the slide lock vise? I have actually thought about making a second one to go on the South Bend mill. In a t-slot table the clamping screw for the split block could also lock it to the table with a t-nut making all adjustment and movement fast and easy from the top of the table. When I don't need it I can just loosen the knob and slide it out of the way.

I don't know how flimsy of material you plan to drill, but anything heavy enough to not buckle when clamped in a vise works in the step jaw just fine. I drill aluminum sheet as thin as .080 as needed. depending on the alloy could go thinner. Much thinner and I use double stick tape or painters tape and super glue to a backer. The sacrificial backer would then clamp up in the vise just fine. They are small. but there is a vertical groove and a horizontal groove milled in the moving jaw of the vise for round stock, and there is no reason I couldn't use a 5C collet block in it either.

For reference. I once made a fixture for milling paper. Plane old ordinary .003 thick printer paper. Talked about it on this group. I used it to create neatly printed custom button labels for a hybrid phone system back when I was still contracting.

Its my understanding that riser blocks for mills were options. Not included. You unbolt the head, lift it up, slap in the riser block, and bolt it back together. I wouldn't mind an additional six inches on my South Bend, but usually I can bolt on a right angle plate, and hang the part off the table if I need to drill something longer than my Z clearance. I have to swing the head to one side so the long part can clear the knee, but its made to do that.

I had to remove the hard jaws to clamp 6

I had an RF-31 for a while. I didn't get much use out of it, but I seem to use my South Bend knee mill a lot. A true 5HP (Running on 7.5hp VFD) spindle makes short work of some roughing and truing jobs even if I do have to turn the handles.

drill and bought an 18 lb 6"

The big advantage of the slide lock is it can't spin, its light weight, and its easily removed or installed. Of course you can make it any size you need.

I may not have done an adequate job of describing the application. The taper pin is not for "joining" or "aligning." Its to be used as a removable core.

--------------------- Thanks. I have to assume normal use unless otherwise specified. I enjoyed the problem solving of custom machine design, repurposing what was available to new uses.

Did you look a the slide lock vise?

--------------------------------------- I have used one that I wasn’t all that impressed with, mainly for the limited range and sensitivity of clamping forces. I drill and mill 0.030" aluminum and clear plastic, usually over a wood backer it may or may not be attached to, with tee slot clamp hold-downs as needed. An example is cutouts for the rectangular panel meters I've mentioned. 0.030" is stiff enough after being folded into a box.

I had to use it a couple times before I got a feel for it. Now it just stays on the drill press all the time. If it had a quick release jaw it would be even better. Remember. You make it any way you need it. I made the one I posted pictures of as a "universal", but I might make it differently if I had a particular application for it. The biggest thing I like about it is it almost totally eliminates any chance of the spinning saw blade.