Gunsmithing Chamber Reamer Not Clearing Chips

[Praeger]

Yesterday I chambered a Krieger SS barrel in 6.5 Creedmoor and noticed the reamer wasn't clearing chips. The reamer cut normally up to the shoulder/body junction. Past that point I was going to take about .100" per pass, but noticed by .060" that no chips were being cleared through the flutes. I stopped and withdrew the reamer and the reamer had been cutting, but the chips were compacted in the flutes inside the hole being cut. The chips were tightly packed and most popped out when the reamer was withdrawn. While the feed rate was slow, I could feel increasing resistance by .040" - .050".

The reamer was a new PTG finish reamer w/live pilot on a Manson floating reamer holder. The reamer and bore were well oiled, and the feed rate was about .010" per 5-6 seconds. I'm using a PM 1340GT lathe at 90 rpm. After each pass the reamer was removed, blown clear of all chips, as was the chamber. I inspected the reamer and found no visible defects.

The chamber finish was fine, and I continued but was forced to withdraw and clear the reamer every .040". No chatter or noise, just forced to make many small passes. The end product was fine, but my previous experience has been that following the same procedure, chips flow evenly from the flutes and are not compacted. Any ideas?

 

[Dlwheel]

I have the identical setup except I use all JGS stuff.
I err on the other side. I initially take .060 passes. but finish with .025 passes.
I have the flush system, but never got the pump to set it up. I don't think I do enough to justify a $$$$ of a pump.

 

[Gene Poole]

Coolant flush is the way to go. I can't believe how much time I wasted the old way; plunge, pull back, power off, detach, rinse blow down, re-oil, repeat.

I usually go 0.125 at a time and pull back just to check, but never see any chips, but pulling back a bit allows the coolant to flush at full volume over the reamer.

 

[Dlwheel]

I probably need to get it done. I have all the plumbing.
Did you make a spider for your 1340?
-david

 

[Rubicon Precision]

That sounds about right without pressurized flush.

 

[DAVETOOLEY]

Some reamers are better than others but I would never expect chips to just work their way out like a twist drill. Chip size and shape, reamer flute depth etc all influence how deep you can go. Roughing in the chamber will save you a lot work and wear and tear on your reamer.

 

[Praeger]

Some reamers are better than others but I would never expect chips to just work their way out like a twist drill. Chip size and shape, reamer flute depth etc all influence how deep you can go. Roughing in the chamber will save you a lot work and wear and tear on your reamer.

I see what you mean about the difference between a twist drill bit and a reamer. It's just that in my case, virtually no chips were cleared and I hadn't seen chips compact this way before - so much so that they popped off the reamer as it was being withdrawn and cleared the end of the chamber hole.

I've been thinking about a roughing reamer. I mostly chamber 6 & 6.5 Creedmoor and 308. Any issues if I simply use the smallest common size, in this case a 6 Creedmoor rougher, as a rougher for any of the three chamber sizes?

 

[Praeger]

I probably need to get it done. I have all the plumbing.
Did you make a spider for your 1340?
-david

Yes, 1/4-28 set screws with brass insert. Had to slightly enlarge the spindle hole in the gear cover.

 

[Snuby642]

I worked around a machine shop for a long time. I did small projects when the real machinists were not available.

In the early days they used black strap molasses/ heavy oil. Then they went to coolant. Before I left they were using cold air blowers.

I used one on a small gantry mill and was fantastic. Cleared chips kept tool cool and no mess.

I ran mostly aluminum.
But the big boys ran every thing with the cold air setup. Not hard to set up if you have a lot of shop air.

May be worth a look?

 

[DAVETOOLEY]

I see what you mean about the difference between a twist drill bit and a reamer. It's just that in my case, virtually no chips were cleared and I hadn't seen chips compact this way before - so much so that they popped off the reamer as it was being withdrawn and cleared the end of the chamber hole.

I've been thinking about a roughing reamer. I mostly chamber 6 & 6.5 Creedmoor and 308. Any issues if I simply use the smallest common size, in this case a 6 Creedmoor rougher, as a rougher for any of the three chamber sizes?

Watch the shoulder diameter. Those have different body tapers.
I use JGS spiral fluted core drills for the meat and potato work here. For the odd stuff a twist drill followed by a short truing pass with a boring bar for alignment. A roughing reamer never made sense to me on a manual machine. It has the same cutting characteristics as a finish reamer. Slow w/o a flush system.

https://cdn.shopify.com/s/files/1/0062/6986/1957/files/JGS_Precision_2015_Catalog_Gun_Gunsmithing_Gunsmith_Tooling.pdf?6377771576127556889

 

[Dlwheel]

I need to bite the bullet and get a spider made. I’m using Viper’s Jig. It works, but I know the spider would be better.
Is that a friction fit?
-David

Yes, 1/4-28 set screws with brass insert. Had to slightly enlarge the spindle hole in the gear cover.

 

[Praeger]

I need to bite the bullet and get a spider made. I’m using Viper’s Jig. It works, but I know the spider would be better.
Is that a friction fit?
-David

No, there are three set screws (also brass tipped). Not much torque is transmitted to the spider, but I didn't want to have to fight it if I needed it removed. I made a few minor changes, but here's the design I worked from.

 

[Dlwheel]

Excellent. Thanks for that.

 

[SIDS01]

I have the flush system, but never got the pump to set it up. I don't think I do enough to justify a $$$$ of a pump.

The hardware for this was less than $250. The pump is ~$120 on eBay. It took less time to set up than I saved the first time I used it. There are 3 gallons of water based coolant in the green 5 gallon pail.

The pump is a Shurflo 8000-812-288, knowing what I know now, I'd buy the 8000-812-289.

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The relief is internal to the pump. It runs 45-60 psi, depending on the barrel and reamer.

 

[Gene Poole]

I use a carbonator pump ($50 on ebay). I had to modify it by changing the spring in the internal relief. It would put out over 100 psi otherwise. Tuned it down to about 15 psi which works for me.

I use a Deublin rotary fitting on the muzzle end.

 

[Dlwheel]

I’m really grateful for all this info. I’m getting ready to set it all up finally. Thanks for your help

 

[Dlwheel]

No, there are three set screws (also brass tipped). Not much torque is transmitted to the spider, but I didn't want to have to fight it if I needed it removed. I made a few minor changes, but here's the design I worked from.

Looking at the layout, i saw David Best names in the corner. I’ve known him from years ago in the woodworking world. He is an amazing innovator.

 

[Dlwheel]

The hardware for this was less than $250. The pump is ~$120 on eBay. It took less time to set up than I saved the first time I used it. There are 3 gallons of water based coolant in the green 5 gallon pail.

The pump is a Shurflo 8000-812-288, knowing what I know now, I'd buy the 8000-812-289.

https://www.ebay.com/itm/SHURFLO-PU...285&hash=item1a79ebbb5a:g:eek:hUAAOSw~~NcrkMD

The relief is internal to the pump. It runs 45-60 psi, depending on the barrel and reamer.

I got my PM lathe with the coolant system added on, thinking I could use it. I never tried, but I was told it wasn’t powerful enough. So it just sits.

 

[LRI]

To the OP:

I ran into this very kind of stuff almost a decade ago. It's what compelled to me to pursue a different path.

First, create the problem statement: Shits in the way and it doesn't want to move out of the way.

Why?:

1. Chip gullets are small and not very deep.
2. Poor fluid exchange due to a pilot that basically behaves like a wine cork.
3. Chip formation is a combination of strings and coffee grounds, they pack in like a snow drift and don't want to move.

Solutions I found:

1. Reduce the flute count. This makes room for chips to run through. -A bigger drainage ditch...
2. Shitcan the conventional pilots and run a fluted one. Fluid exchange is everything. HSS tooling doesn't support this very well due to the retention screw using up all the available real estate.
3. Add staggered chip breakers to the tool so that you break up the stuff into a manageable size.

I once reached out to JGS. I was told by someone that this was not possible and the tone suggested I was just being another DB gun queer. Little did they know I've been having my tools made this way for about 7 years now.

It's a 48 second cycle time to chamber a 6.5mm Creedmoor. That's with .400" pecks. A 338 Lapua is just under 3 minutes. 600rpm/.004"/rev feed.

No shit.


LRI now has its own line of reamers. Its in its conception right now, but we have successfully made our first. A little 20 caliber version of the 6mm XC that one of the staff wanted to play with. I ran that tool like I stole it in one of our K&P brand barrel blanks. Roughly 40 seconds and it was done. Finished it with green scotchbrite.

Don't let a staggered chip breaker fool you. It has zero negative effect on surface finish. I have close to $30k in tooling done exactly like this.

C.

1st fired case:

 

[Dlwheel]

To the OP:

I ran into this very kind of stuff almost a decade ago. It's what compelled to me to pursue a different path.

First, create the problem statement: Shits in the way and it doesn't want to move out of the way.

Why?:

1. Chip gullets are small and not very deep.
2. Poor fluid exchange due to a pilot that basically behaves like a wine cork.
3. Chip formation is a combination of strings and coffee grounds.

Solutions I found:

1. Reduce the flute count. This makes room for chips to run through.
2. Shitcan the conventional pilots and run a fluted one. Fluid exchange is everything.
3. Add staggered chip breakers to the tool so that you break up the stuff.

I once reached out to JGS. I was told by someone that this was not possible and the tone suggested I was just being another DB gun queer. Little did they know I've been having my tools made this way for about 7 years now.

It's a 48 second cycle time to chamber a 6.5mm Creedmoor. That's with .400" pecks. A 338 Lapua is just under 3 minutes. 600rpm/.004"/rev feed.

No shit.


LRI now has its own line of reamers. Its in its conception right now, but we have successfully made our first. A little 20 caliber version of the 6mm XC that one of the staff wanted to play with. I ran that tool like I stole it in one of our K&P brand barrel blanks. Roughly 40 seconds and it was done. Finished it with green scotchbrite.

Don't let a staggered chip breaker fool you. It has zero negative effect on surface finish. I have close to $30k in tooling done exactly like this.

C.

That is awesome. JGS slotted the screw that sits ahead of the pilot, but that’s it. What you’re doing makes sense.







1st fired case:

 

[Praeger]

To the OP:

I ran into this very kind of stuff almost a decade ago. It's what compelled to me to pursue a different path.

First, create the problem statement: Shits in the way and it doesn't want to move out of the way.

Why?:

1. Chip gullets are small and not very deep.
2. Poor fluid exchange due to a pilot that basically behaves like a wine cork.
3. Chip formation is a combination of strings and coffee grounds.

Solutions I found:

1. Reduce the flute count. This makes room for chips to run through.
2. Shitcan the conventional pilots and run a fluted one. Fluid exchange is everything.
3. Add staggered chip breakers to the tool so that you break up the stuff.

I once reached out to JGS. I was told by someone that this was not possible and the tone suggested I was just being another DB gun queer. Little did they know I've been having my tools made this way for about 7 years now.

It's a 48 second cycle time to chamber a 6.5mm Creedmoor. That's with .400" pecks. A 338 Lapua is just under 3 minutes. 600rpm/.004"/rev feed.

No shit.


LRI now has its own line of reamers. Its in its conception right now, but we have successfully made our first. A little 20 caliber version of the 6mm XC that one of the staff wanted to play with. I ran that tool like I stole it in one of our K&P brand barrel blanks. Roughly 40 seconds and it was done. Finished it with green scotchbrite.

Don't let a staggered chip breaker fool you. It has zero negative effect on surface finish. I have close to $30k in tooling done exactly like this.

C.

I saw this on your FaceBook page a week or so ago and emailed your shop. Just heard back from Kalli, and she said I'd need to supply a print, each made to order, carbide only, $500 each.

Any chance you'll be producing reamers in HSS? I'm just turning barrels for myself and guys I shoot with using SAAMI spec reamers.

 

[LRI]

I saw this on your FaceBook page a week or so ago and emailed your shop. Just heard back from Kalli, and she said I'd need to supply a print, each made to order, carbide only, $500 each.

Any chance you'll be producing reamers in HSS? I'm just turning barrels for myself and guys I shoot with using SAAMI spec reamers.

We are only offering tooling in carbide, sorry.

 

[Praeger]

The hardware for this was less than $250. The pump is ~$120 on eBay. It took less time to set up than I saved the first time I used it. There are 3 gallons of water based coolant in the green 5 gallon pail.

The pump is a Shurflo 8000-812-288, knowing what I know now, I'd buy the 8000-812-289.

https://www.ebay.com/itm/SHURFLO-PU...285&hash=item1a79ebbb5a:g:eek:hUAAOSw~~NcrkMD

The relief is internal to the pump. It runs 45-60 psi, depending on the barrel and reamer.

What's the filter you're running?

 

[schutzprecision]

SIDS01 looking at building same set up. My grizzly lathe has a coolant system but it is pretty low volume and pressure. Why would you get the 289 pump vs the 288

 

[SIDS01]

It's a cheap whole house water filter on the suction side. This one was on clearance and being able to switch to the second filter isn't needed. The flows for this system are so low and short that a single filter intended for a house is overkill. The primary filter is the magnets that hold the cake pan to the lathe bed under the chuck. The cake pan drains directly to the 5 gallon bucket when in use. The through hull fitting on the cake pan is an easy way to install a drain, but it also stops most of the stuff that lands between the magnets.

289 has a 120 psi relief, the 288 is 100 psi, and the 289 generally doesn't cost any more. As a practical matter, it wouldn't really make a difference because mine isn't on the relief when it's running. Even with a 223, the pumps gets 1.4 gallons of water based coolant past the bushing with 60 psi. You probably do want to avoid the 45 psi pumps intended for RV use.

This is a hobbyist system, and it's intended for water based coolants. It's cheap, compact, simple to set up and a chip won't kill that pump. I've never tried running oils through it. The pressures with oil would be higher.

I did 2 chambers old school and decided something needed to change. It's a huge time saver and the chamber finishes are great.

 

[Dlwheel]

Thanks again, SIDS01. I've got the 289 on the way.

 

[Danny1788]

A chamber flush system is the only way to go. I built mine a few years ago and have only had to change the filters once. Dozens of barrels chambered with it. I use 4 gallons of ridged dark cutting oil and 1gallon of automatic transmission fluid. Small 3/4Hp pump.
I use a super swivel from EBay and drill and tap the end of muzzle 1/8NPT that screws right into the barrel