Band Saw Hole Centering Plugs

[JoeLee]

I don't know what else to call these. Made five of these yesterday, various sizes, because I had to come up with a way to accurately cut these holes equally through the center.
My scribe lines aren't accurate enough and are there just for visual comfort. After the first hole is located it's all DRO's from there on.



This is what I have been ending up with. Discrepancies of up to .020 or so. It's really hard to eyeball the blade in the center of the hole. I tried measuring and a couple other ideas all of which were nerve racking and I kept ending up with the same error.

You can see that the inside of the holes are all perfectly aligned and that's all that really matters, DRO's work great.



So, I came up with this idea............ I turned the plugs to about .001 under the various hole sizes and then slit them on center in the mill.

My band saw blade cuts .045 wide and I had a slitting saw that cuts about .0455. The slit fits the blade with no wiggle. If I can minimize my error down to about even .010 I would be happy.
With these plugs I should be able to do that and the set up will be much less nerve racking and quicker.



JL...............

[metalmagpie]

I'm sorry - bandsaw plugs? Are you talking about zero-clearance inserts? I made up a batch of those awhile back. Didn't even monkey with mills or lathes. I took some 0.093" A2 tool steel and also ABS the same thickness, and had the inserts cut out with a waterjet. I may be the only guy with a Rockwell Delta 28-365 20" vertical bandsaw whose inserts don't move radially because I added a tab on the outside to stop them rotating. Here, have a look - metalmagpie

[Doozer]

I made one for my DoAll 1612 vertical band saw, as it was missing when I bought the saw.
I used 1/2" plate. Turned it on the lathe. Made a step on top so it fits down into the hole and
catches the counterbore feature of the table, and drops in flush. I just cut the slot using the
actual bandsaw. Used a piece of wood for a temporary rest, and just marked a center line
with magic marker and cut the slot. I just need one. Why are you making so many?
Going to sell them ? Mine being 1/2" thick has been lasting for years and still looks new.
If you have the space, thicker is better. Like I said, simple lathe job. Looks like you went
through some to-do in making yours.

-Doozer

[JoeLee]

I'm sorry - bandsaw plugs? Are you talking about zero-clearance inserts? I made up a batch of those awhile back. Didn't even monkey with mills or lathes. I took some 0.093" A2 tool steel and also ABS the same thickness, and had the inserts cut out with a waterjet. I may be the only guy with a Rockwell Delta 28-365 20" vertical bandsaw whose inserts don't move radially because I added a tab on the outside to stop them rotating. Here, have a look - metalmagpie

Well, I did say that I didn't know what to call them, but were talking two different things here. Mine are for alignment / centering purposes only on my horizontal band saw. Yours are for covering the hole in the table of your vertical band saw.

JL..............

[ezduzit]

I just use the bandsaw's fence. Comes out exactly on center of hole; in this case a 1.835" diameter hole to mount a bronze sea strainer in a sailboat.

[Dan Dubeau]

Nice job Joe. Bandsaws are often thought of as low precision tools, and technically they are, but they can be repeatable, and if you jig/fixture them up can be used to do repeatable precision work. not everything has to be a milled finish. I've made a few quick and dirty bandsaw jigs over the years for production jobs, and they worked great for the job they were intended for.

I like the bandsaw inserts too MM. I turned one from 6061 a few years ago, but never thought to add the anti rotation tab. That's a great idea. When this one wears out in 20 years, I'll make a new one with it, if I remember .

[JoeLee]

I'm sorry - bandsaw plugs? Are you talking about zero-clearance inserts? I made up a batch of those awhile back. Didn't even monkey with mills or lathes. I took some 0.093" A2 tool steel and also ABS the same thickness, and had the inserts cut out with a waterjet. I may be the only guy with a Rockwell Delta 28-365 20" vertical bandsaw whose inserts don't move radially because I added a tab on the outside to stop them rotating. Here, have a look - metalmagpie

Just to clear up any confusion and I should have included this pic in my OP. But, here is how they work. Once the strip is properly located and locked down the plug is removed.



JL.................

[JoeLee]

Nice job Joe. Bandsaws are often thought of as low precision tools, and technically they are, but they can be repeatable, and if you jig/fixture them up can be used to do repeatable precision work. not everything has to be a milled finish. I've made a few quick and dirty bandsaw jigs over the years for production jobs, and they worked great for the job they were intended for.

I like the bandsaw inserts too MM. I turned one from 6061 a few years ago, but never thought to add the anti rotation tab. That's a great idea. When this one wears out in 20 years, I'll make a new one with it, if I remember .

True. But I fine tuned mine to cut pretty accurately. Repeatability works as long as the parts can be properly located.

JL............