Boring customs

[Dodgy Loner]

I am contemplating the best way to go about boring a large number of identical holes into wooden blocks (into the end grain, specifically). The difficulty is that the holes that I need are not cylindrical. Currently I am completing the task by drilling a cylindrical 1" hole into the wood blocks using a drill press, then mounting the blocks onto a lathe to hollow out the approximate shape that I am after. However, this is somewhat difficult and very tedious - not to mention highly variable - and I am trying to come up with a more efficient and precise solution. The shape that I am shooting for (as well as approximate dimensions) is below:



What would your solution to this problem be? I am not necessarily looking for a low cost solution or a high cost solution. I am simply trying to identify the best solution, and will consider just about any ideas. The critical aspects are quality of the results (I am looking for a smooth cut that will require minimal cleanup), efficiency, and repeatability.

Currently, I am leaving towards a custom bit that I can use on my drill press and that will cut the desired shape. If this is indeed the best solution, then do you have any recommendations for companies that could make the cutters? Any pitfalls that you can think of? Thanks in advance for your help. If you need more information to formulate an answer, then ask away.

[Red Clay Hound]

Now you have peaked my curiosity as to what it is you are making. ???  Apparently you are needing to make a fairly large number of these holes.  My first thought is the same as yours - a custom drill bit.  Don't have any suggestions on sources though.  Maybe someone on here will know someone who can make a bit.

[Axe Handle Hound]

That's a pretty interesting set of dimensions to work with.  I'd have to suggest either a custom ground tapered spoon bit or a custom made router bit that you could put in a plunge router.  You'd certainly want to use a variable speed router with a bit that size and I think I'd make a sort of upside down router table.  Have the router mounted to a plate that will hold it and the block you're routing securely so you can just plunge the router without worrying about holding on for dear life. 

[WDH]

You might take a standard spade bit and grind it to the required dimensions.  That would be a cheap solution.  You could get it very sharp, and maybe it would do OK in the end grain.  That way, you would have the control of the drill press to ease the bit into the wood. 

[beenthere]

Thinking maybe a bit with inserted teeth like the teeth in the spiral planer heads, but with the tooling that you can set the teeth at the desired depths. ?? :

Chip removal may be tricky if this idea even is possible. But air blown down the center of the bit shank might blow the chips up and out.  :

[Dodgy Loner]

You might take a standard spade bit and grind it to the required dimensions.  That would be a cheap solution.  You could get it very sharp, and maybe it would do OK in the end grain.  That way, you would have the control of the drill press to ease the bit into the wood.

I have actually ground spade bits to custom shapes before with success. But I am thinking that chip clearance may be a big problem with a hole this big. Plus, I think HSS or carbide will be a necessity. The number of holes I am thinking of is in the thousands. Maybe more.

[Dan_Shade]

if you have that many, I'd contact a drill manufacturer, or a router bit company for a custom bit.

[Dodgy Loner]

I don't think a router is the tool I will be wanting to use for this application. The hole is simply too big. I have thought some about milling machines. I don't want to buy a milling machine (not planning to drill quite that many holes just yet), but I was wondering if the bits could be used in a drill press? From the looks of them, it would appear that the bits would cut wood very cleanly. This is a primary concern. Anybody out there with milling machine experience? I know they can be used on wood, but not sure if this wood be a good application or not.

[Dan_Shade]

you could put the router bit in a drill press or milling machine.

have you contacted a tool maker?

If you spec out your requirements, they can probably give you a hand.

[beenthere]

Does the shape have to be repetetive, with little tolerance from one to another?
Or can the shape gradually change as the bit wears and can then be resharpened?

Thinking of a mini size rotary well drilling head that has three cutter wheels. But would be very expensive to make (I'd think).

[Ianab]

I would look to get a custom made router bit to that profile. Drill the hole first to hog out most of the material, 1" drill bit?

Once the bulk of the material is removed from the centre a big plunge router with a custom bit should clean up the hole to that profile.

You don't want to spin a 1.75" bit at full router speed, but a big variable speed router like my Makita 3126c spins a 2" dia flat bit on my slab surfacer with the speed set to 2 out of 5 on the speed control. The electronic controller keeps the torque up even with the slower RPM, and the cutter's speed stays correct for the bigger router bit.

Ian

[Nomad]

     A custom made router bit would be the way to go.  I'd prefer a mill for the boring myself, although a heavy drill press would do the job.  Lots of companies will make custom bits.  Whiteside Machine is one, although I've never dealt with them.  (A quick search just found 'em online.)
     Older used milling machines can be had relatively cheaply, but moving them is a bear  They ain't light.

[SwampDonkey]

Do a search for "reamers"  Dodgy and see what you come up with. I don't know if you can get one blunt enough.

[red oaks lumber]

i would find a shop that has a cnc machine. have them qoute the job, that way you know a fixed price and a cnc will hold tight tolorences and give you consistinacy every part.

[Larry]

I'm also thinking of a custom router bit.

In the past I have worked with WDR sales to make custom moulding knives.  Bill, the owner has been around for a long time.  He has made a lot of custom and one off tooling.  Give him a call.  He may have an idea that we haven't thought of here.

This is one of their products.  I've never seen one and have no idea how it works but it's certainly worth exploring.

http://www.wdr-sales.com/routerbit.htm

Just another thought.  A overarm router rather than a plunge router might be the right tool.  If a slower speed is required a custom machine similar to a drill press might work.  I picked up a custom machine that uses an air cylinder to run the drill bit up and down.  It was used to drill one end grain hole in novelty wood train whistles by the thousands.

[isawlogs]

 I would look into making it with a reamer as SD sayes, you can cut and sharpen a reamer for the bottom of your hole. They are on the $$ side, first try it with a small one  ;)  We often used reamers on  structural steel to help out bolting the peices together. I would probably used compressed air to help with the chips, as the reamers do not carry chips well....  ;)
  You could also make the hole a two step , one cut to make the bottom with a wood bit, then a reamer to get your tapper .

[Dodgy Loner]

you could put the router bit in a drill press or milling machine.

have you contacted a tool maker?

I hadn't considered putting a router bit in a drill press. That's something to consider.

I haven't contacted a toolmaker, because I've had very bad luck just picking out an ad on the internet and crossing my fingers. I sent $300 worth of blades to an tool sharpener a few months ago and got back the most useless, mangled tablesaw blades I've ever laid my hands on. I was hoping for recommendations this time.

Does the shape have to be repetetive, with little tolerance from one to another?
Or can the shape gradually change as the bit wears and can then be resharpened?

The shape could change over time with sharpening with little effect on the final product.

In the past I have worked with WDR sales to make custom moulding knives.  Bill, the owner has been around for a long time.  He has made a lot of custom and one off tooling.  Give him a call.  He may have an idea that we haven't thought of here.

This is one of their products.  I've never seen one and have no idea how it works but it's certainly worth exploring.

http://www.wdr-sales.com/routerbit.htm

Thanks for the link, Larry. That looks like it would be an good, affordable option.

i would find a shop that has a cnc machine. have them quote the job, that way you know a fixed price and a cnc will hold tight tolorences and give you consistinacy every part.

Thanks, but I'm not looking to outsource the production.

Do a search for "reamers"  Dodgy and see what you come up with. I don't know if you can get one blunt enough.

A reamer-type bit is actually exactly what I had in mind to begin with. I would need to get one custom made, though, I'm sure.

I would probably used compressed air to help with the chips, as the reamers do not carry chips well....  ;)

That's a good idea, and it would be easy enough to set up. Compressed air would probably help if I went the way of a router bit, too. Lots of good ideas, thank you all. This is exactly the kind of brainstorming that I needed! Feel free to add more ideas, and I will report back as I make progress.

[Brad_S.]

Just another thought.  A overarm router rather than a plunge router might be the right tool.

That was what popped into my head too. AKA a pin router, they were replaced by CNC and can therefore be found very cheaply these days. I picked up a Delta RU50 for $400 but I haven't gotten around to using it yet. Bought it for a project that I have been planning to do for 25 years now. Someday......

[ely]

may be easier to have someone remold the candles to fit your drill bit holes....

[Dodgy Loner]

Just another thought.  A overarm router rather than a plunge router might be the right tool.

That was what popped into my head too.

Interesting, I had never heard of an overarm router, but that looks like it would be perfect for what I have in mind. Maybe if things go as planned, that would be the next step.

may be easier to have someone remold the candles to fit your drill bit holes....

DanG, now why didn't I think of that? ???  Oh yeah, I'm not making candle holders :D

Sorry for being so vague, but I can't go around throwing my brilliant, million-dollar ideas on the interwebs before they are ready for production, now can I? ;) Just kidding. Maybe I will earn a few bucks on the side, and y'all will be the first to know if I decide to take my idea into production.

[SwampDonkey]

Me thinks you are running into the same trouble as me looking for fine yarn or fine SS strip wire. Everything is industrial quantities or off shore. This continent is going to $%^$^%$ :D

[shelbycharger400]

swamp.. i found you a company that had wire close to your spec,  too bad they didnt want to ship to you.

tapered reamer almost seems like the ticket for this job. Id go with a 2 flute, but it has to be a grind that cuts on the sides and the bottom.   I think its called a mortising bit

You could do something like the lumberjack countersink bit

[drobertson]

My first thought was to have a special bit made, whether it is carbide or hss resharpening will come into play. 'the other thought is changing the geometry of the hole. What would be the most cost effective solution. If the existing geometry has to be met, I see a two stage operation, one roughing hole, followed by the finishing pass..  Just by your sketch it appears you only have a few degrees of taper per side, not knowing the bottom dia. and the radius call out. Is a clean top edge important? is the bottom radius important?  This size of  this bit is costly no matter what it is made from, this is definetly an interesting problem.  Good luck,, david

[North River Energy]

First post, might as well jump right in...

If you have already determined that your product is viable, and you want to produce it in house, (in large numbers) I would be inclined toward the use of a lathe with a turret tail-stock.  Probably one with lever actuation.
Not all that familiar with cutting end grain, but were it aluminum or similar, I would go with a pilot drill, then your 1.75, maybe a large end mill for the floor of the hole, and the final cut with a 'form tool', which you could probably make yourself.

A dedicated set of jaws for the lathe chuck would be in order for fast changeover.  This would require a bit more care on consistency of stock sizing.

The advantage to the lathe is the chips will tend to self clear, the surface finish will probably be better than the drill press/mill, and the form tool for the final cut can be fabricated in house by welding/brazing, and finish grinding.

Once set up, it should also be rather fast.

Using a custom reamer might work, so long as the chip load per 'plunge' doesn't exceed the flute volume.  The upper flutes might not self clear, however, and a dull reamer is harder to sharpen than a form tool.

Of course, more specific and set criteria might dictate another approach.

[Dan_Shade]

welcome to the forum, North River Energy.

Do you run a machine shop?