Heat shrink holder already heated once, for testing. Problem?

fmari --MariTool- · Dec 5, 2016

When we make endmill holders not only do we check concentricity inside the bore at several depths but we also put a gage pin in the holder tighten the set screw and check runout of the pin at 2x dia and 4x dia. This is very important and can sometimes show problems in grinding that may be hard to catch with just an indicator on the indside bore.

In the future when we make shrink fit holders we plan on doing the same gage pin test. The problem is that we will need to heat the holder to do this. So some customers will get a brand new holder that has been heated once and will show the typical color change on the nose. Is this a problem for you guys? I plan on putting a note on those holders explaining that this holder is still new and just cycled once for testing purposes. I personally wouldn't mind, but I would like some feedback from you guys.

Finegrain · Dec 5, 2016

Hi Frank,

I wouldn't mind!

What are your intentions on selling a heater for your shrink fit line? Are you figuring that shops that buy shrink fit holders already have a heater?

Regards.

Mike

dstryr · Dec 5, 2016

Let me know if you need a tester

.
Just got an Lyndex shrink machine to replace my hand held torch....

Zahnrad Kopf · Dec 5, 2016

Frank,

Personally, I would not mind at all and would have a warm, fuzzy knowing that the manufacturer cares enough to insure their work. Especially given the note.

Given that I just placed one order with you, and am fingering the button on another order, I am VERY interested in when you will be offering these.

Either way, put me on an update list for these! In other words, < waving hand wildy > Over here! Over here! Over here!

Aside, it is very heartening to hear someone take the time to inspect their work as you describe. I have oft been adjudicated crazy for doing the exact same thing when making parts, being admonished that the clock ( indicator ) "tells you everything you need to know".

As usual, nice work.

TDegenhart · Dec 5, 2016

Slight OT, but the questions I have are: once the tool is in the holder who do you remove it for replacement. Press? How many tons? Two, are there a fixed number of replacements that can be make before the holder is damaged? Three, how small can the tool be before this method no longer works. I mention this last one as there is a combination of wall thickness and inside diameter will cause the ID to shrink as temperature increases.

Tom

dstryr · Dec 5, 2016

TDegenhart said:
Slight OT, but the questions I have are: once the tool is in the holder who do you remove it for replacement. Press? How many tons? Two, are there a fixed number of replacements that can be make before the holder is damaged? Three, how small can the tool be before this method no longer works. I mention this last one as there is a combination of wall thickness and inside diameter will cause the ID to shrink as temperature increases.

Tom

You heat the holder back up and pull the tool out?

I wouldnt bother with tools smaller than 3/16 shanks
1/8 tools are very hard to set and in my opinion are a Giant PITA. You can source very good endmills 1/8 and sub 1/8 diameter on 3/16 and 1/4" shanks easily and the cost difference is very mininmal.

TDegenhart · Dec 5, 2016

dstryr said:
You heat the holder back up and pull the tool out?

I wouldnt bother with tools smaller than 3/16 shanks
1/8 tools are very hard to set and in my opinion are a Giant PITA. You can source very good endmills 1/8 and sub 1/8 diameter on 3/16 and 1/4" shanks easily and the cost difference is very mininmal.

I don't think so. The reason the shrink fit works is that when the holder is heated, it expands. Insert the tool. As the holder cools, it contracts around the tool. Once the tool/holder are at uniform temperature, the tool is held by compressive stresses, but it also means that if you try to heat the holder, you will also heat the tool and at the same rate at the interface. Therefore, depending on the rates of thermal expansion for the two metals, the gripping forces will either not change or be only slightly changed.

Tom

aarongough · Dec 5, 2016

TDegenhart said:
I don't think so. The reason the shrink fit works is that when the holder is heated, it expands. Insert the tool. As the holder cools, it contracts around the tool. Once the tool/holder are at uniform temperature, the tool is held by compressive stresses, but it also means that if you try to heat the holder, you will also heat the tool and at the same rate at the interface. Therefore, depending on the rates of thermal expansion for the two metals, the gripping forces will either not change or be only slightly changed.

Tom

You should check out some videos on shrink fit tooling. Heating it back up to remove the tool is indeed how it works...

aarongough · Dec 5, 2016

Frank:
I wouldn't mind at all given the note.

I would be interested in trying some short gage length 1/4" holders... I know most people go for shrink-fit when they're looking for clearance and longer gage length, but for my purposes minimizing runout is the ideal, and doing that with a short gage length would be great as I don't have any clearance issues!

-A

DanielG · Dec 5, 2016

TDegenhart said:
I don't think so. The reason the shrink fit works is that when the holder is heated, it expands. Insert the tool. As the holder cools, it contracts around the tool. Once the tool/holder are at uniform temperature, the tool is held by compressive stresses, but it also means that if you try to heat the holder, you will also heat the tool and at the same rate at the interface. Therefore, depending on the rates of thermal expansion for the two metals, the gripping forces will either not change or be only slightly changed.

Carbide and steel have differing coefficients of thermal expansion.

Milland · Dec 5, 2016

fmari --MariTool- said:
In the future when we make shrink fit holders we plan on doing the same gage pin test. The problem is that we will need to heat the holder to do this.

Hi Frank,
One thought - you may not want to use steel gage pins for this test, due to steels having a higher CTE and usually being more difficult to remove from heat shrink tooling, and also steel pins may relax or shift more from the extra heating/cooling. But regular carbide blanks may not have the accuracy needed to be a useful gage pin. Maybe someone like Van Keuren (Plain Reversible Plug Gages | Van Keuren) can supply them in X class?

If this is all stuff you've considered please ignore...

fmari --MariTool- · Dec 5, 2016

When you heat the holder to remove the tool the holder heats up first, before the shank. Also most of the time the shank is carbide which expands much less that steel. No force should be used to remove the shank from the holder.

Still working on a shrink machine. So far not too happy with what I have found, but still working on it.

I can't say for sure when we will offer heat shrink holders. Hopefully in a few months but I have said that before. It looks like we will start with the 3" gage length first. That seems to be popular.

Zahnrad Kopf · Dec 5, 2016

TDegenhart said:
I don't think so.

No, that is indeed how it works, Tom.

EDIT - Frank beat me to it.

Zahnrad Kopf · Dec 5, 2016

fmari --MariTool- said:
I can't say for sure when we will offer heat shrink holders. Hopefully in a few months but I have said that before. It looks like we will start with the 3" gage length first. That seems to be popular.

Frank, positively put me on a notification list if you are putting one together. Also, since I am relatively close, I will be more than happy to test for you if you decide to do such. With or without consideration. I'll be happy to help either way. I'm already a happy customer and will be happy to be able to get these from you instead of other vendors.

vettedude · Dec 5, 2016

TDegenhart said:
Tom

Heat transfer is not instant, that's why it takes a while to cook a turkey.

wheelieking71 · Dec 5, 2016

vettedude said:
Heat transfer is not instant, that's why it takes a while to cook a turkey.

Mmmmmm, turkey....... :leaving:

On a serious note: The pre-tested/checked tool would not bother me at all!

TDegenhart · Dec 5, 2016

Thank you all, I was thinking of steel tools not carbide.

Vettedude Yes, you are correct. Play a oxy torch on the outside of a piece of steel and see how long it takes for the center to get red. Quite awhile. What that means here is that the heat transfer is slow enough for the tool and holder to warm the same at the interface. An RF induction heater would be the best here in that carbide is none conductive so it would stay cool while the steel heats. And induction heating is rapid.

Now for the other question, how small will this process work?

Tom

Perry Harrington · Dec 5, 2016

Frank, just have some cards printed up that say your shrink-fit tools are 100% tested and that's why the discoloration.

fmari --MariTool- · Dec 5, 2016

We wouldn't be testing all of them. It all depends on how problematic or how easy they run. I am anticipating checking by heat shrink every 10th holder, but that may change.

Zahnrad Kopf · Dec 5, 2016

fmari --MariTool- said:
We wouldn't be testing all of them. It all depends on how problematic or how easy they run. I am anticipating checking by heat shrink every 10th holder, but that may change.

Frank, I am curious - How are they normally checked? I have used shrink fits and Tribos holders, but I have never given much thought to how they are checked? Obviously, one can push from the rear and look for slip, but what amount of force is expected to properly hold one in place?

For what it is worth, even the Tribos ones suck with 1/8" shanks. I would always place a stop bar behind them so that the end mill would not walk up into the holder.

Heat shrink holder already heated once, for testing. Problem?

Titanium

Diamond

Diamond

Diamond

Diamond

Diamond

Diamond

Stainless

Stainless

Stainless

Diamond

Titanium

Diamond

Diamond

Stainless

Diamond

Diamond

Titanium

Titanium

Diamond

Similar threads