Tips for drilling on the lathe?

[geoffholden]

I'm hoping that someone can give me some assistance with drilling on the lathe.
I have a Mastercraft 8x12 mini lathe (I think it's the same as the Harbor Freight one, but with a 1"-8tpi headstock).
I don't seem to have any trouble drilling with a 7mm bit, but the I constantly stall the lathe with bigger bits. I've tried starting with a smaller bit as a pilot hole, and that helps some, but I still stall it out.
I'm guessing that that because the lathe is variable speed, it just doesn't have the torque at low speed to remove that much material. But that's just my guess, and I'd like to be proven wrong.

 

[southernclay]

What speed are you drilling? Are your bits sharp? What material are you drilling?

I drill around 500 rpm, sharpen bits with drill doctor.


Sent from my iPhone using Penturners.org mobile app

 

[geoffholden]

What speed are you drilling? Are your bits sharp? What material are you drilling?

I drill around 500 rpm, sharpen bits with drill doctor.


Sent from my iPhone using Penturners.org mobile app

I'm drilling at 750 rpm (as slow as the little lathe can go). Only drilling wood so far, stabilized burl most recently.
The bits seem to be sharp (brand new), but I don't have a drill doctor yet.
Last night I ended up finishing the holes with a hand drill, after getting them started straight on the lathe.

Sent from my Nexus 5X using Tapatalk

 

[Skie_M]

Using Harbor Freight Mini Wood Lathe 8x12 1/3HP ...


I pre-turn all my blanks round and chuck them in a 3-jaw chuck ... this step isn't required for this to work, it's just what I do.

I use the sharp end of a tool like a skew to make a center hole in the end of the spinning blank (or you can use a center drill).

I then start the bit slowly, feeding in 32ths intervals and immediately backing off 1/8th of a turn to avoid constant drag bogging down the motor ... this is done at minimum speed (750 RPMs). If the wood cuts easily, I take larger "bites" of the wood at a time.

As I progress into the blank, I increase the speed of the lathe to compensate for the drag against the bit so that I can continue the drilling progress, stopping every half inch to inch or so to back the bit out to clear the cuttings. If the wood is extremely dense or I am dealing with some kind of acrylic or something like trustone, I stop 1/4 to 1/3 of the way through for 20 minutes to let the bit cool down, and return to it later, stopping again after another such interval of drilling, till I am through the blank.

I haven't used my Drill Doctor much yet, but I have just bought a brand new set of drill bits from Harbor Freight .... the 29-bit Ti/N set with 135 degree split point tips, and they are cutting quite nicely.


Stabilized Burl will cut like a dense wood or acrylic, you'll want to let your bits cool off and take small bites while drilling .... as though you were working with Ebony.

 

[monophoto]

I'm guessing that that because the lathe is variable speed, it just doesn't have the torque at low speed to remove that much material. But that's just my guess, and I'd like to be proven wrong.

Bingo. That's exactly what is happening. Your lathe has a DC motor, and varies the speed by varying the voltage applied to the motor. Torque is proportional to the product of the fluxes created by two voltages, or by one voltage and a magnet in the case of permanent magnet motors. So reducing the voltage to reduce speed also reduces torque. Sorry - that's just physics.

Obviously, there are a number of factors that make drilling more difficult (and that require more torque) - dull bits, larger diameter holes, etc. So switching from a 7mm bit to a larger bit will require more torque, and even through the bit is new, there's no guarantee that it is actually sharp.

You didn't say what size hole you were trying to drill, but my experience is that if you drill a small pilot hole, and then increase the diameter by successively boring with progressively larger bits, you generally can often work around a torque limitation. But if you try to jump directly from a very small hole to a far larger bit, you sill can encounter problems. Also, you still need a sharp bit.

There are several tricks you can try:
- start with your 7mm bit, and then enlarge the hole in small increments. - after drilling the pilot hole, increase the lathe speed to increase the available torque. Obviously, you need to be careful to not cause the bit to overheat because that can damage the bit and crack the blank, so drill a short distance, and then back the bit out to clear the swarf.
- are you drilling for pens such that you have to glue tubes into the hole? If not, then lubricating the bit with wax, or adding a little oil will help. But don't do that if you have glue something into the hole!
- sharpening the bits may be helpful. A couple of swipes with a diamond card or paddle might be all that it takes.

 

[SteveG]

You should be aware that a "NEW" bit is not necessarily a sharp bit. I recently posted my opinion on another thread...


Quote:"With some years of pen turning under my belt, I have found great value in using HIGH QUALITY drill bits for pen making. This resulted in my having nearly all the typical "kit" size bits being of nice quality. (Nice quality= straight shank, tough and strong metals, truly sharp right out of the box and staying sharp a long time, non-clogging surface treatment of the flutes.) I recently bought A full set ...fraction,number,letter bits...and am very happy to have traded a significant amount of my hard earned money for this set. I bought the Norseman Super Premium brand, which can also be found online in individual sizes. There are a number of other quality brands, of course. These far out-shine anything to be found at Lowes, HD, etc."

Try it...you will like it!! I doubt that YMMV in this case.

If you continue in pen turning, a method for sharpening drill bits will become a necessity. The Drill Doc is the most popular answer, but be aware, that tool comes with a little bit of a learning curve too.

Sharp bits are part of the answer to your issue, as seen by the responses here already. The better you get at penturning, the more enjoyable it becomes!

 

[TonyL]

You are getting all of the right advice from better minds and more skilled hands than mine. However, if you have skype, I can watch what you are dong and perhaps help.

Here's my account tony.lobelljr

 

[geoffholden]

Bingo. That's exactly what is happening. Your lathe has a DC motor, and varies the speed by varying the voltage applied to the motor. Torque is proportional to the product of the fluxes created by two voltages, or by one voltage and a magnet in the case of permanent magnet motors. So reducing the voltage to reduce speed also reduces torque. Sorry - that's just physics.

Obviously, there are a number of factors that make drilling more difficult (and that require more torque) - dull bits, larger diameter holes, etc. So switching from a 7mm bit to a larger bit will require more torque, and even through the bit is new, there's no guarantee that it is actually sharp.

You didn't say what size hole you were trying to drill, but my experience is that if you drill a small pilot hole, and then increase the diameter by successively boring with progressively larger bits, you generally can often work around a torque limitation. But if you try to jump directly from a very small hole to a far larger bit, you sill can encounter problems. Also, you still need a sharp bit.

There are several tricks you can try:
- start with your 7mm bit, and then enlarge the hole in small increments. - after drilling the pilot hole, increase the lathe speed to increase the available torque. Obviously, you need to be careful to not cause the bit to overheat because that can damage the bit and crack the blank, so drill a short distance, and then back the bit out to clear the swarf.
- are you drilling for pens such that you have to glue tubes into the hole? If not, then lubricating the bit with wax, or adding a little oil will help. But don't do that if you have glue something into the hole!
- sharpening the bits may be helpful. A couple of swipes with a diamond card or paddle might be all that it takes.

Yeah, that's as I figured, I'm actually trained in electrical engineering. I didn't think that the cheap lathe would have any feedback in the motor controller, but again, was willing to be proven wrong.

The holes are for gluing brass tubes in, unfortunately, so wax or oil is out of the question. Is there anything else that could be used as a lubricant? Water or water with dish soap maybe?

 

[Charlie_W]

I know you might not want to hear my answer but from what I have read in this thread, you may need to move on up.....to a lathe with more umph!
Good Luck

 

[jttheclockman]

There are times when you just need to step up in equipment quality. I see this so many times in the scroll sawing world. People continue to buy these cheap scroll saws and expect them to perform as well as a $1000 saw and get frustrated and quit when this does not happen. If you are serious about this hobby. step up to a better lathe and either sell this one or use it for a backup or for polishing like everyone else does. If you have a drill press, tune that up and use that for drilling. many people put down the use of a drill press for drilling blanks but many times it comes down to poor quality tool or not tuned properly. Taking a tool out of the box and expecting great things is not how to set up your tools. Learn the proper use and tune up of them. Today there is so much video and tutorials on the net that just about anything out there has been discussed. Just need to do the leg work. Good luck.

 

[Woodchipper]

You should be aware that a "NEW" bit is not necessarily a sharp bit. I recently posted my opinion on another thread...

Very true. I tried drilling lignum vitae...it was like drilling through tool steel! Upon recommendation from my engineer son, I slowed the DP down to 1,100 rpm and sharpened the needed bit. Worked great.
I know it can take a bite out of the budget but I agree....a more powerful lathe might me something in the future.

 

[TonyW]

As I've not got a Drill Doctor (yet), is it possible to sharpen a drill bit by hand please, say by holding a spinning bit against a grind stone?

TIA

TonyW

 

[Skie_M]

As I've not got a Drill Doctor (yet), is it possible to sharpen a drill bit by hand please, say by holding a spinning bit against a grind stone?

TIA

TonyW

Safest method I can think of to RELIABLY sharpen a drill bit equally for both chutes is to chuck it in a 3-jaw chuck on your lathe or drill press securely, and gently touch up the cutting edges with a diamond card or plate while it spins at high RPMs .... keep water on the diamond card/plate for cooling.




If you are VERY steady with your hands, you could try using a grinder or sanding station to touch up the very tip of your bits ... make sure the grind stone has been freshly dressed so that it cuts a good clean swathe, or if you are using sandpaper, fresh would be best.

You could theoretically do the same via use of a Dremel and some grinding tips or sanding discs ... the issue with these two methods is that you could take more material off one side than the other, leading to that flute being the only leading edge, which will cause the bit to want to cut in that direction ....

This cutting more in one direction doesn't do much if the BIT is spinning in a hand drill or a drill press .... but when the bit is STATIONARY while you are drilling on a lathe, the bit will tend to wander in the direction that it wants to cut in, resulting in flexing the bit in that direction, possibly bending the bit, giving you an oversized hole, possibly breaking the bit, causing the bit to get stuck in the hole when you try to clear chips, overheating, and dulling the single cutting tip very fast. (All these problems come lumped together, good luck!)

The first method, where you spin the bit and touch up the cutting edges, is probably the most reliable method to get an even cutting edge .... but you'll still need to touch it up by hand by giving the cutting edges of the bit a relief angle, in order for that cutting edge to be able to dig into the material you are drilling into, rather than just riding on the surface area of the drill bit tip and just getting very hot.

In order to do this, you can keep the bit in the lathe or drill press if you are comfortable with the working angle, or take the bit to a vice and clamp it securely ... then take the same diamond card or a good file, and WITHOUT TOUCHING THE VERY EDGE, add an extra 5 to 10 degree sweep back from the edge to allow for the edge relief.

If you can do all of this by hand, you're on par with a top machinist .... (they buy drill doctors for a reason!)


The way a Drill Doctor works is simple .... the bit is clamped within the flutes, which gives a guaranteed cutting angle against the tip. All standard style twist bits have the same proportional makeup, so the clamping system is spot on every time, guaranteeing that you only remove minimal material from the tip each use.

As you ROTATE the bit by hand, the clamping bit holder is made to ROCK and change it's angle as you turn it. This allows for sharpening the cutting edge of the bit AND grinding the relief angle in a single motion for every pass .... you rotate the holder until you hear little to no grinding action for full rotations ... this means that the cutting edges are even and equal on both sides and the relief angle has been met.

If your Drill Doctor has the split point port, it can only be inserted in 2 different orientations .... use BOTH and grind both sides evenly ... examine the point of the bit to ensure that there is sufficient material in the center of the bit for strength, and that your cutting edges have been split well to discourage wandering in the bit cutting action.

 

[jbg230]

People continue to buy these cheap scroll saws and expect them to perform as well as a $1000 saw and get frustrated and quit when this does not happen. If you are serious about this hobby...

.

...or use it for a backup or for polishing like everyone else does.

Hmmm, I finally have to disagree with JT on this one. I actually don't quite understand the generality of "people" who do this and "people" who do that. And how he knows what "everyone else does" is quite something. I know he means well and his advice of tool set up and gaining information from other sources is sound, but I have a "cheap" scroll saw and it works exactly like I need it to. I think the meaning of, "serious about this hobby", is different for us all. I'm serious about it. I don't make a true living at it, but I'm using my pens for networking, so yeah, I'm serious about it. But I don't need a $1000 scroll saw and I use a Harbor Freight mini lathe which has made awesome pens and beautiful tool handles.
AND - now that I have taken the advice as mentioned above (from previous posts), my HF lathe drills my blanks, my really dense exotic wood blanks, with perfection.

I wouldn't give up on your lathe. I would try the techniques that have been offered. I will bet that it solves your problem.
Jake

 

[Skie_M]

I'll agree with you that John seems to have a slightly disparaging outlook towards those of us who cannot afford the high quality brand name tools, but he's got an excellent point or two.


What you pay for in a Harbor Freight tool is the basics, in my opinion ... it's NOT SET UP right out of the box, and you pay for that in misalignment issues and other minor issues all around the tool, plus the quality of the motor and blades may be a little lacking .... the motor performance itself is limited compared to the top shelf models John is used to.


What you have to understand about the higher quality tools that John prefers is ... not only can the motor work harder and longer and you have less issues with your initial blades, you ALSO have less work to do to align and tune up your tool to your liking.

CAN you tune up a Harbor Freight tool to perform (in terms of single cut performance ability) with a high quality tool? YES. You just have to know what you're doing (see youtube videos)

CAN a Harbor Freight tool output as much work as a high quality tool? NO. Know the limits of your tool, though, and you should never have an issue getting the job done in the end ... it just may take longer!

 

[jttheclockman]

People continue to buy these cheap scroll saws and expect them to perform as well as a $1000 saw and get frustrated and quit when this does not happen. If you are serious about this hobby...

.

...or use it for a backup or for polishing like everyone else does.

Hmmm, I finally have to disagree with JT on this one. I actually don't quite understand the generality of "people" who do this and "people" who do that. And how he knows what "everyone else does" is quite something. I know he means well and his advice of tool set up and gaining information from other sources is sound, but I have a "cheap" scroll saw and it works exactly like I need it to. I think the meaning of, "serious about this hobby", is different for us all. I'm serious about it. I don't make a true living at it, but I'm using my pens for networking, so yeah, I'm serious about it. But I don't need a $1000 scroll saw and I use a Harbor Freight mini lathe which has made awesome pens and beautiful tool handles.
AND - now that I have taken the advice as mentioned above (from previous posts), my HF lathe drills my blanks, my really dense exotic wood blanks, with perfection.

I wouldn't give up on your lathe. I would try the techniques that have been offered. I will bet that it solves your problem.
Jake

Hello Jake. Once again I find myself having to defend a statement I made here on this site. I am glad you are paying attention to what I say and it does not fall on deaf ears. You can agree or disagree with anything I say because that is what a forum is all about.


Read my post #10


But what you and many others do is take my words out of context and shorten them to what you think you read. I have been scrolling for well over 30 years and have visted many forums dedicated to scrolling and WHAT I HAVE SEEN (you forgot to put those words in there) that many people buy or want to buy a scroll saw and wind up buying a cheaper version and then come to the forums and start asking how to fix this or that, why does my blade do this or that, why can't I scroll straight. I have seen this so many times over the years and most often it leads back to a cheaply made saw. There are a few mid priced saws that will outshine any cheap saw including a Harbor Freight and if you did any sawing on them you would realize right away the differences. Did not say anything about stepping up to the $1000 saws but the difference between those saws and a mid range saw also shows through. These people then do get frustrated and believe all saws are a pain and leave the hobby. Yes I have seen this. You may not believe me but it is true. I had a friend that bought a Ryobi saw and could not get that thing to work well at all. Let him use my RBI and he was hooked. He saw the difference right away and that was coming from a novice.

The same thing happens with lathes and you can do a search here for I have been here since 2005 and have read many many times of problems on cheaper lathes that show up here. In this case the lathe is underpowered for what the OP is trying to do. Does it make it a bad lathe, it may not but it makes it an inefficient lathe that now has limits. Did I say to go and buy a One Way Lathe, no I did not but there are so many better options that will not get you frustrated.

People what you have to understand and yes I get it not everyone has an unlimited budget and I do not either, but over the years I found you try to buy the very best tool you can afford right away so you are not buying twice. This makes the cost of your tool even higher than what you could have paid from the beginning. Maybe you have to save a little more before you jump in or do some borrowing to get a better tool. I do not have the answers because we are all individuals. But one thing I will tell you and know for fact is that a better quality tool will serve you better, longer and has better resale value if you get out of the hobby. Try selling that Harbor freight saw or lathe.

So Jake if the tools you have work for you then great I hope you do well and for Skie, not sure what he does and I probably never will. He is all over the place.

I am not afraid to voice my opinion and you may agree or not and that is fine. what I say is not gospel. I am no guru here. Just someone who has been woodworking for most of my life. I own quite a few tools and have a shop pretty much equiped with what I need. are the tools in it the best on the market, absolutely not. I would love to own different tools. But the ones I do own I know what they can do and how well they perform. I will not use a tool that I will have to sarifice something for to get a job done. That sacrifice may just be an injury. So take what you want out of what I said in this thread and any others that I post to but I stand behind what I said. Good luck and Happy woodworking.

 

[Skie_M]

Always glad to read anybody's opinion on anything, John ... thanks for your input, as always!

You are right, though ... I am all over the place on hobbies .... just to list them all right now would make this post longer than your last post... :biggrin:

 

[jttheclockman]

Always glad to read anybody's opinion on anything, John ... thanks for your input, as always!

You are right, though ... I am all over the place on hobbies .... just to list them all right now would make this post longer than your last post... :biggrin:

This you are. I have a hard time trying to figure out your main interests. But give you credit you have your toe in alot of things and that will broaden your knowledge base. Have fun.

 

[geoffholden]

Thank you guys for all your help and comments.
I knew getting into this that the lathe was small and not very powerful, I was just a little caught off guard with stalling it out at low speeds.

I'm going to try slowly stepping up bit sizes in 32nds or 64ths to get to the proper size, and increasing the speed a little to overcome the drag on the bit when I'm deeper in the hole.
A drill doctor is going to be on my wish list, and possibly a small press, if I can make some room in the garage this summer. Otherwise I'll just keep finishing the last quarter or so of depth with a hand drill, since it seems to be working so far.

 

[Skie_M]

Slowly stepping up won't work in many cases ... the corners of the bit can get grabby, and without a decent center to guide the tip of the bit, it can veer off course on you ... especially if one side is cutting more than the other!


Drilling into something as hard as metal, as long as the bit is sharp on both sides and cutting effectively on either side, and the work is fully clamped down, the bit will spin and cut effectively... this works fine on a Drill Press, when stepping up in increments to reach your final hole size. The issue here is ... the BIT is spinning.

Drilling into anything on the lathe .... the bit is held stationary, if it is not cutting effectively on both sides, it will veer off course. As mentioned already, the corners of a bit can get grabby, tending to bite deeply into softer material and then tear out or blow apart your blank. You don't want to see what I mean... In effect, without the material in the center of the blank to STOP the bit from digging deep into the blank material, you get an uncontrolled cut that attempts to bite as much as the flute can hold, which is far too much.


For drilling woods on the lathe ... unless you're dealing with a slightly dull bit that will force it to stay centered (but heat up a ton), you'll want to start with your center drill and go directly to the finished drill size. I've attempted before to try to re-drill a hole that was drilled undersized, and blew it apart ... was one of my very first attempts at segmenting. It MIGHT work for a really dense hardwood, but it certainly does NOT work for a softwood or quite likely the lighter hardwoods.



Other issues ... when you get near the end, even if you managed to drill with pilot and undersized bits, as the next size bit clears the end hole - if it's not clamped SECURELY, the bit will blow out the back as it exits the blank and grab the remaining material around the walls of the hole that haven't been cleared by the cutting action yet .... it will then attempt to corkscrew it's way into the material due to the cutting flutes on the bit, slamming the bit into the back of the chuck if it's not an open through-hole design.

Once it's reached the back of the chunk, the bit will either cut through the remaining material or lever-jack it right out of the chuck's grip ... either stalling the motor or ripping your blank out of the chuck. (Thankfully, the blank will still be on the drill bit, so it wont go flying off, but your chuck and your lathe will not like you very much... and may even stop speaking to each other nicely.) Another possibility is that the chuck may have a GOOD grip on the blank ... so the bit will pop the taper free and it will begin spinning, possibly making contact with the back of the chuck.



In short ... a good sharp balanced cutting bit of the correct size is, in my opinion, the best way to drill your barrels on the lathe, with a simple center drill or divot in the center of the blank just to guide the tip at the start.

 

[jbg230]

Well described! I've learned this well from recent experience.

 

[jbg230]

John,

I understand what you're saying. I also understand that posting an idea, opinion, or advice on a forum may be interpreted differently among different readers. I'm glad we can all share our thoughts and critiques and at times, our disagreements. Ever since I found this forum, I felt lucky we had you as one of the active, contributing and expert members. I guess it was just the generalizations I read that prompted my post. Certainly there are plenty of hobbyists that do not get frustrated and enjoy their entry level tools, but I agree that if lack of performance results in someone giving up, it would be a shame that a higher quality tool wasn't either used initially or that the "cheap" one wasn't replaced with something better.

So I certainly agree about what you're saying regarding higher quality tools. Some woodworkers should and need to "step up" and obtain higher quality tools, but then again, some don't need to. Like you said, "if it works for you- great". Some just need to (I for one) set up, tune up, and maintain a tool properly to get it to perform up to the standards they're looking for. Like many things in our lives, if you then don't get the results you're looking for, then quality definitely needs to be taken into consideration.

I look at the budget issue a little differently though. Value and time play a key role for me. I can afford a professional quality lathe, band saw, scroll saw, etc. And I'm sure I would notice the difference in a top notch saw or lathe. The question is: Is that difference valuable to me? I've decided that for now, it's not. Safety is different. Spend whatever it takes to make it safe. Quality dust collection made sense to me. Quality sharpening, quality turning tools that keep an edge, quality drill bits, make sense to me. If I thought my tools were inherently unsafe, I would get what makes sense and is safe. But of course this is widely subjective. As you know, everyone has to set their own standard. Each of us has to decide if the feature of a SawStop table saw makes sense for them, for example.
It's not the price point for me (and it may not be for other people as well). It's time and value. Just like with my photography equipment and musical instruments, I started out with basic stuff and as I knew I was committed, I invested in better stuff. Like you said, "if you're serious about this hobby…". I should have read that as, " if you think you'll continue to be committed to the hobby in the future …"
For me, the dollars spent to get started is just discretionary spending. If I'm still doing this in a few years and upgrade to higher end tools, I wouldn't resent myself at all for the dollars spent in the beginning. It's a big time waster for me to try and sell things. Anything really worth keeping would go to my kids. Resale value would not be how I would evaluate a tool. So I would much rather start small, know if I'm going to be committed, and then invest with bigger dollars. The time between "spending twice" would be too far spread out to play a role.

I completely appreciate your approach in getting the best quality you can at the time. I just look at it differently in some respects.

I thank you for all that you share on the forum and I look forward to more learning and more posts that make me question whether I'm "doing it right".
Jake

P.S. I know this topic is talked about all the time and deviates from the main question. I'll move on and save time by reading about things like, "Which glue is better?"

 

[Skie_M]

Which glue is better?...

Oooohhh boy ... THAT's a whole nother can o worms there, boyo!

 

[suefox51]

What is the preferred brand of drill bit (if any) - or/and, what brand do you use and why?

Thanks,
Sue