Help please with boring head on a drill press

[John T]

Don't buy drill rod. It isn't straight.

Very true.

[farmersammm]

I get my blanks from Wholesale Tool. About 1/3 the price of the other guys for nice ground round blanks. https://www.wttool.com/ I can't find the blanks on their website, but they're in the paper catalog.......might have to call them

[smithdoor]

Note you can use a drill press for boring.
1) You need use the quill clamp so do not get tapper bore.
2) The quill feed you need a long handle for find feed.

Dave

I started a new thread to be more specific with what I need help with. I was so happy I got my drill press aligned and squared up to the backhoe frame. I tried the boring head with the brazed carbide boring bars but it didn't go well. The 1st boring bar had the biggest shank but the carbide chipped trying to take a very light cut about half way down the bore. I didn't have the bore ground perfectly square top to bottom. Then I tried a boring bar with a smaller shank and it didn't have a big chip taken out but seemed to round itself and dull. I set the carbide pretty much straight up and down after watching a couple video's on the net. They didn't cut well at all and caused a lot of vibration. It might have been more due the carbide chipping or dulling.

This tells me I need to strap and clamp the drill press better and get it as rigid as possible to the backhoe frame. I should be able to do this pretty easily. I plan to put a block of wood between the base of the drill press and the lower swing pivot (they should be very close to parallel) and then either use some 1/2" ready-rod and clamp them together or use a ratchet strap. Then I plan to put another block of wood cut to length between the drill press column and the upper pivot I'm boring and put a ratchet strap on it. I can also clamp the drill press table to the underside of the top pivot I'm boring with a wood spacer. I think this should hold the drill press as solid as possible top and bottom. I kind of doubt there'd be any warranty on the boring bars but the worst they can say is no. I read the import boring bars aren't very good and often need to be re-ground so they actually work. I plan to go to a machine shop supply to get a better quality boring bar. Should I try to find an HSS boring bar or would a better quality brazed carbide work? What about spending more for one with a replaceable insert and what type of insert? I've also read you need to turn faster with carbide but I think I'm at about 180 RPM which might be a little fast already. I'm doing a little under 3" bore. Is straight up and down the correct angle for the cutting head? What do you guys with machining experience suggest to give me the best chance of success? Thankfully I haven't ruined anything expect a couple cheap boring bars.

[Welder Dave]

I ordered a US made brazed carbide boring bar. The cobalt HSS are no longer available from the same supplier, Michigan Drill. Looks like I need to get the drill press super solid and use some positive rake on the boring bar. The guy I talked to also said carbide doesn't like really light cuts but likes speed and maybe I need to increase the speed to help limit chatter. He tried looking up a chart but couldn't find one. He did have a little cardboard slide indicator and suggested about 260 RPM for a hole slightly less than 3 inches. Does this sound about right?

[M J D]

I ordered a US made brazed carbide boring bar. The cobalt HSS are no longer available from the same supplier, Michigan Drill. Looks like I need to get the drill press super solid and use some positive rake on the boring bar. The guy I talked to also said carbide doesn't like really light cuts but likes speed and maybe I need to increase the speed to help limit chatter. He tried looking up a chart but couldn't find one. He did have a little cardboard slide indicator and suggested about 260 RPM for a hole slightly less than 3 inches. Does this sound about right?

Sounds about right once you get into an even cut. Your going to have to go a lot slower until you get into a somewhat even cut. Think of it like roughing out a square or hex shaped piece of stock on a lathe. Interrupted cuts are always a pain, carbide or hss.

[Welder Dave]

Maybe I can use the cheap boring bar to show me where the high spots are and grind them down a bit with the plug wheel so there less of an interrupted cut?

[Oldiron2]

Maybe I can use the cheap boring bar to show me where the high spots are and grind them down a bit with the plug wheel so there less of an interrupted cut?

If you coat the inside of the hole with (quick drying) spray paint, a felt pen or Dykem, even a mild steel 'tool' will rub the paint off where contact is made, showing where to do the grinding.

BTW, don't you have a bench grinder?

[52 Ford]

If you coat the inside of the hole with (quick drying) spray paint, a felt pen or Dykem, even a mild steel 'tool' will rub the paint off where contact is made, showing where to do the grinding.

BTW, don't you have a bench grinder?

Yep. In order from best to worst, I'd say it goes Dykem, Sharpie/permanent marker (I prefer Markal, personally), paint pen (again, I like Markal), then spray paint (I suggest you try Dupli-Color Engine Enamel. It dries fast and it's fairly cheap. It's my go-to paint for most things), then you have other stuff, like drawing a bunch of lines with a soap stone or scuffing the surface 90 degrees to the cut direction using sand paper. Really anything to give a good indicator.

[Oldiron2]

Yep. In order from best to worst, I'd say it goes Dykem, Sharpie/permanent marker (I prefer Markal, personally), paint pen (again, I like Markal), then spray paint (I suggest you try Dupli-Color Engine Enamel. It dries fast and it's fairly cheap. It's my go-to paint for most things), then you have other stuff, like drawing a bunch of lines with a soap stone or scuffing the surface 90 degrees to the cut direction using sand paper. Really anything to give a good indicator.

I went in the order of what he's likely to have and considering the rough nature of his need, not what would be best for precision work in another's shop or garage...but I appreciate your providing more good information on the subject.

Another sometimes useful method, when one can't or won't weld supports on to machinery, is to use 2-part epoxy to attach plates, using as much surface as possible. Heating allows easy removal later; warming can reduce the cure time.

[52 Ford]

Oh, another way to add a an "indicating layer" to your part (brain fart - can't come up with the right word )... soot from a candle actually works fairly well.

Not saying you should go out their and cover that borewith candle soot. Just figured I'd throw it out there so you can add it to your cerebral toolbox. Dykem or some other layout fluid general works better.

OH... duhh... I said candle, I'm talking to welders... an oxy-acetylene torch would get the job done just the same. The first time I saw someone use soot for layout "medium" I was watching a clock maker. No welders or oxy-acetylene torches in the shop. An A/O torch would work a lot quicker that trying to get a candle up to the work to get soot on it LOL

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[Welder Dave]

I don't have a bench grinder. The machine is basically out in the boonies but at least inside a pole shed. I power everything with a small generator. I think just about anything would make a good indicating mark on the bore for what is higher. Primer dries fast. I was thinking maybe instead of starting the cut part way down the bore where it's definitely higher, it might be better to start at the top of the hole and work down until there is noticeably more material to remove. Then I could bring the boring bar in a little and work on the bottom portion of the bore. For final sizing go the full the length of the bore. Does this make sense? I also thought of a way to get a really slow feed. Turn the nut down on the depth gauge to limit how far the spindle goes down and then with pressure on the handle slowly loosen the nut allowing the spindle to lower. I'd have to look to see if it will fit but would be ideal if I could use a ratcheting wrench for loosening the nut. Could maybe even use a bungee cord on the handle so I'd just have to worry about the nut. It is fine thread so should lower very slowly. Really hard to be somewhat consistent just using the handle.

If the new brazed boring bar doesn't work and all I could get was drill rod, would a piece 2 1/2" to 2 3/4" long be straight enough?

[smithdoor]

I have used in field for bench grinder is a 7" hand grinder today it would be a 4½" hand grinder.

Do you have a welder on site?

Dave

I don't have a bench grinder. The machine is basically out in the boonies but at least inside a pole shed. I power everything with a small generator. I think just about anything would make a good indicating mark on the bore for what is higher. Primer dries fast. I was thinking maybe instead of starting the cut part way down the bore where it's definitely higher, it might be better to start at the top of the hole and work down until there is noticeably more material to remove. Then I could bring the boring bar in a little and work on the bottom portion of the bore. For final sizing go the full the length of the bore. Does this make sense? I also thought of a way to get a really slow feed. Turn the nut down on the depth gauge to limit how far the spindle goes down and then with pressure on the handle slowly loosen the nut allowing the spindle to lower. I'd have to look to see if it will fit but would be ideal if I could use a ratcheting wrench for loosening the nut. Could maybe even use a bungee cord on the handle so I'd just have to worry about the nut. It is fine thread so should lower very slowly. Really hard to be somewhat consistent just using the handle.

If the new brazed boring bar doesn't work and all I could get was drill rod, would a piece 2 1/2" to 2 3/4" long be straight enough?

[Welder Dave]

I have a couple 5" grinders.

[smithdoor]

I used a hand grinder when putting metal roofing on.
We drill thousands of holes to screw the roof on and you use a lot of drill bit. So I would use hand grinder for sharpening drill bits.

Dave

I have a couple 5" grinders.

[farmersammm]

Indicating high spots on what will be an interrupted cut is ok I guess. Generally your first scratch cut will tell you where the high areas are.

Unless you really know that your weld buildup is excessive(and this is a good thing up to a point), you really might not want to go messing around with a grinder. You'd probably want to kill yourself if you ground a low spot, and had to rebuild the weld.

Carbide loves speed in smooth cuts. It does NOT love speed in an interrupted cut because it's brittle. Think of hitting a brick wall at 60mph.........over and over and over and over and over and over. Slow shallow cuts.

[bcguide]

Just my opinion but with the amount of time and effort to mount your drill press I would build a boring bar set up with some bearings.
After watching the video posted using a boring bar I thought that front axel bearing sets from a 4x4 truck kind of resemble his bearing set up.
Back to using your drill press the quill? (Is that the correct term for the part that drops down?) Is not going to be ridgid enough to accurately bore further more the flexibility will cause the bit to bite deeper and jam or break.
You addressed the other problem the rake is going to pull the cutter down again jamming or breaking the cutting tool.

[bcguide]

I would use a high speed tool bit for this. You could buy 5 or 6 grind them at home and bring them to the job. Grind a couple for rough cuts and some for finishing cuts.

[smithdoor]

I agree

I use mostly HS tool bits as grind to shape need for job.

I have boat load of carbide too but A36 steel need a high rake angle to give a good cut and it easier to grind HS tool bits.

Dave

I would use a high speed tool bit for this. You could buy 5 or 6 grind them at home and bring them to the job. Grind a couple for rough cuts and some for finishing cuts.

[Welder Dave]

HSS boring bars are very hard to find as are HSS blanks you can grind yourself. That's why I'm wondering if a 2 3/4" piece of drill rod would be straight enough? I made a few mistakes on my 1st attempt so am trying to rectify them for the 2nd attempt.

[Oldiron2]

HSS boring bars are very hard to find as are HSS blanks you can grind yourself. That's why I'm wondering if a 2 3/4" piece of drill rod would be straight enough? I made a few mistakes on my 1st attempt so am trying to rectify them for the 2nd attempt.

I don't recall seeing the type of boring head you have; I have a few Criterion of the style shown below, all which can hold a round tool perpendicular to the bore (i.e. sticking out the side). The problem with using plain drill rod it that it's usually only available in either Water- or Oil-hardening, neither which is as hard or heat-resisting as is wanted for a steel-cutting edge. Lathe tool bots, drill bits, etc. usually use M2 or greater. Here's one site I quickly found that sells tool steel like this (should go to 1/2" M2 rounds):

https://toolsteelservice.com/product...m2-round-12-2/

If you had access to used inserts, they could be silver-soldered onto a piece of recessed drill rod to make custom carbide tooling; carbide grinding generally requires using a silicon carbide stone.

For this one-time use, the bottom half of a worn out 1/2" drill bit (assuming that's the size you need) could be ground to suit your needs.

[farmersammm]

I don't recall seeing the type of boring head you have; I have a few Criterion of the style shown below, all which can hold a round tool perpendicular to the bore (i.e. sticking out the side). The problem with using plain drill rod it that it's usually only available in either Water- or Oil-hardening, neither which is as hard or heat-resisting as is wanted for a steel-cutting edge. Lathe tool bots, drill bits, etc. usually use M2 or greater. Here's one site I quickly found that sells tool steel like this (should go to 1/2" M2 rounds):

https://toolsteelservice.com/product...m2-round-12-2/

If you had access to used inserts, they could be silver-soldered onto a piece of recessed drill rod to make custom carbide tooling; carbide grinding generally requires using a silicon carbide stone.

For this one-time use, the bottom half of a worn out 1/2" drill bit (assuming that's the size you need) could be ground to suit your needs.

That's a fair price for HSS blanks.

I'm not sure whether we know if Dave has the tooling required to make a line boring setup. So I guess he's stuck with what he has on hand. So I guess he's stuck with the boring head he has.

Just in passing.............I totally groove(boy that dates me) on grinding tools. I truly feel that anybody can do it, and it'll make a better machinist out of them when they have a mind's eye picture of what the tools are actually doing when cutting.

[Welder Dave]

I have a similar type boring head although an import. It's not the problem I don't think. I think the cheap import boring bars I got are beyond useless! I cut pieces of wood to use as spacers and tightly strapped the drill press to the backhoe frame at the base and the swing pivot I'm working on. It's much more solid than before. I tried another of the boring bars and increased the speed. I put a slight positive rake on the boring bar. It seemed like it kind of tried to work but when I looked at it, it appeared the cutting point was rounding off. I tried it a little more and then noticed the carbide chipped again at the cutting edge. It does appear the cutting edge is past the center of the boring bar which causes problems. I'll look and see if I have an old 1/2" drill bit I could try and make a cutter out of while waiting for the new US made boring bar. Pretty frustrating to say the least. This is the type of boring bar I ordered. Looks like APT might be a Michigan drill company. Price is almost double in Canada.

https://michigandrill.com/catalog/pr...ucts_id=120551

[52 Ford]

I have a similar type boring head although an import. It's not the problem I don't think. I think the cheap import boring bars I got are beyond useless! I cut pieces of wood to use as spacers and tightly strapped the drill press to the backhoe frame at the base and the swing pivot I'm working on. It's much more solid than before. I tried another of the boring bars and increased the speed. I put a slight positive rake on the boring bar. It seemed like it kind of tried to work but when I looked at it, it appeared the cutting point was rounding off. I tried it a little more and then noticed the carbide chipped again at the cutting edge. It does appear the cutting edge is past the center of the boring bar which causes problems. I'll look and see if I have an old 1/2" drill bit I could try and make a cutter out of while waiting for the new US made boring bar. Pretty frustrating to say the least. This is the type of boring bar I ordered. Looks like APT might be a Michigan drill company. Price is almost double in Canada.

https://michigandrill.com/catalog/pr...ucts_id=120551

I'd definitely try slowing down.

Being serious, grab a pillow or something to sit on, get comfortable, and just go SLOW. Slow your RPM down, slow your feed down, whatever you've gotta do. The problem with boring with a drill press is that when you're doing an interrupted cut, you have to be concerned with feed SPEED directly. With a continuous cut, feed pressure is good enough (like drilling).

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[bcguide]

I cannot see you getting any better results with a different boring head. There is no way to make it ridged enough that the cutter will not dig in and chip or break.

Take labparamour up on his offer or build something similar. Buy some hss grind a bull nose cutting bit.
If you get it close maybe you can use a hone to get it to your exact dimensions.

[Welder Dave]

I can slow it back down and after reading of similar results with cheap Chinese boring bars, it's worth trying a better US made boring bar. I was trying to take a very light cut and it made a rough surface I think was because there is no relief and/or the cutting tip is past half the diameter of the boring bar. I can also try making an HSS bar out of a drill bit. I was feeding really slow but I think I can feed the slowest by using the depth stop and slowly loosening it while applying a little down pressure on it.