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dovetail vs no dovetail in 5th-Axis self-centering vise?

tphwi

Plastic
Joined
Mar 3, 2023
Quick question for anyone using self-centering vises on 5-axis machines?

On the fence about whether or not to dovetail blanks or just clamp in 45° serrated jaws
with no prep in 5th-Axis V75100X . Only holding on to 2.5mm (.098") in either case.
Material is 1018CF, 126Bhn.
Large hole is Ø.625" x 2.9" deep and the small hole is Ø.300" x 4.9" deep.

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Do you think the part will move or be ejected from vise if I don't dovetail the blanks?
If I do dovetail the blanks, do you think part will slide in dovetail if not keyed like most
dovetail clamps that I've seen?
 

mhajicek

Titanium
Joined
May 11, 2017
Location
Minneapolis, MN, USA
Depends on how hard you're going to attack the material. 1018 should be soft enough to get a decent imprint, so if you're not going super hard at it, it should be fine without dovetailing.
 

tphwi

Plastic
Joined
Mar 3, 2023
This will be a production job so I want to run all tools in the middle to upper range of their capabilities.
For the Ø.625 hole I want to use a modular (replaceable tip) or indexable (flat-ish bottom) drill.
Solid carbide coolant through for the Ø.300 hole and smaller (not shown in picture).
Not sure how much cutting forces will be required vs the clamping force.
Machine will run mostly unattended with fairly inexperienced operators.
I'm leaning toward dovetailing and keying blank to locate side-to-side for most secure workholding.
If someone has experience with this, or very similar scenario, with this 5th-Axis vise, I'd like to learn
from your experiences. Especially if your experience leads you to believe that stock prep would just
be a waste of time and money. Thanks.
 

Hebrewhammer8

Cast Iron
Joined
May 14, 2009
Location
Bellingham, Wa
The thing about the gripper jaws is if you are putting forces from the side axially into the part then yes they can and will move. This is mostly with larger tools with high tool pressure. I had this happen the most with large SAE porting tools with hella tool pressure when the spot face hits.

I would dovetail prep just to be safe.

On a side note. I just swithed from 5 axis dovetail to Techni-Grip style work holding. It is a billion times better than a regular dovetail as there is no air below the dovetail and the part is fully supported.
 

srp61

Aluminum
Joined
Sep 19, 2009
Location
Dunedin, New Zealand
I haven't used the 5th axis stuff as I decided to go with Lang instead, because I can stamp the blanks and don't have to spend time doing dovetail prep

But I found the 77mm Lang vise could adequately indent soft materials like aluminium or 1018. Although I have the 77mm vice that uses the larger 125mm spindle, which has 20NM more torque than that 5 that axis vice.

I have no problems pushing drills like that in that orientation (solid carbide and Iscar Sumochams) and regularly use a 39mm Udrill with no problems

I think it would be borderline in that vice though
 

gkoenig

Titanium
Joined
Mar 31, 2013
Location
Portland, OR
This will be a production job so I want to run all tools in the middle to upper range of their capabilities.
For the Ø.625 hole I want to use a modular (replaceable tip) or indexable (flat-ish bottom) drill.
Solid carbide coolant through for the Ø.300 hole and smaller (not shown in picture).
Not sure how much cutting forces will be required vs the clamping force.
Machine will run mostly unattended with fairly inexperienced operators.
I'm leaning toward dovetailing and keying blank to locate side-to-side for most secure workholding.
If someone has experience with this, or very similar scenario, with this 5th-Axis vise, I'd like to learn
from your experiences. Especially if your experience leads you to believe that stock prep would just
be a waste of time and money. Thanks.

5th Axis makes a good vise with nice grippy teeth. Easy test is to put the material in and see if tightening to the prescribed torque leaves marks on the material. If it does, I wouldn't bother with the dovetail.

Even if it doesn't, the dovetailing time/effort is going to absolutely obliterate any feed/speed increases you see from running those drills faster.

Issue your folks a nice torque wrench and all they need to do here is follow basic Machinist 101 practices. Expensive, but worth every penny? The Snap On digital torque wrench with audible, visual, and even tactile feedback. If your folks can't manage this simple setup, you have way bigger problems.
 

Orange Vise

Titanium
Joined
Feb 10, 2012
Location
California
Machine will run mostly unattended with fairly inexperienced operators.
I'm leaning toward dovetailing and keying blank to locate side-to-side for most secure workholding.
Until recently, we dovetailed precisely 0% of our stock before heading into OP10 milling.

That's all changing now. We're working our way up to about 80% of all blanks being dovetailed. Reason is exactly what you said... inexperienced labor.

Nothing is 100% fail safe, but dovetailing gets you closer than just about any other method. The dovetail provides a positive lock with pull down, so even if the vise isn't torqued properly, it might still hold the part. The locating dowel not only prevents the blank from slipping sideways, but it forces the blank on center and can also serve as a poka-yoke if needed. The OP0 pre-machining of the blank flattens the bottom face to ensure that it seats properly in the vise or fixture even if the raw blank has defects.

Definitely key the blanks. Your best bet is to ditch the gripper jaws for this application and machine dovetails into steel soft jaws. Soft jaws will provide you with more real estate to add your dowel pin(s).

Dovetail prep is one of these easiest things to automate in a VMC if volume really picks up. We've dedicated a VF4 to nothing but dovetail prep for the entire operation.
 

GiroDyno

Cast Iron
Joined
Apr 19, 2021
Location
PNW
Maybe not applicable for your steel parts but I've seen a modified table saw/router set up to rip dovetails along aluminum barstock before sawing into whatever size blanks were required. Eliminates the more expensive machine time from the stock prep part of the equation...
 

Silent_Man

Aluminum
Joined
Jan 10, 2014
Location
Chicago
You probably will be fine without the dovetail.

I am doing .531" holes in annealed alloy and tool steel with their 5" vise (v562x?) In the same orientation as you show, but probably an inch further out from the jaws. I am using insert tip drill though which really helps vs regular HSS and Co split point grinds.

I too was hesitant at first, but after torquing the vise to max and inspecting the workpiece, there is enough of an indentation that the grip is pretty darn secure.
 

Mtndew

Diamond
Joined
Jun 7, 2012
Location
Michigan
I have one of their vises (before they fixed the jaw lift), I would definitely dovetail it first.
 

5 axis Fidia guy

Stainless
Joined
Aug 17, 2006
Location
Wisconsin
I use a Schunk self centering vise with just the serrated jaws and that things grips hard! even leaves dimples in hard H-13. I guess it depends on how fast you plan on roughing, obviously a dovetail will be stronger but it's more work to put on and take off.
 

tphwi

Plastic
Joined
Mar 3, 2023
Update for anyone interested.

So far so good at 50 parts into run without dovetailing, just holding on by ~.110 serrated jaws
of 5th-Axis V75100X self-centering vise at maximum torque (60NM / 44ft.lbs.).

My research into cutting force created by Ø5/8 solid carbide or modular drill (using Sandvik website)
indicated <600 pounds cutting force. 5th-Axis website claims maximum clamping force at maximum
torque is 22kN (4945 lbs. force). So the chances of the part being pushed out of vise seem to be slim
to none as long as serrations on jaws don't wear down and tool remains in good condition.

FYI we are using a $200 solid carbide, coolant through, double margin, ZCC branded drill from Shars.
We are using several others in smaller sizes on another job and so far I'm impressed. Does anyone
Know where these are made? China? SKorea?

Anyway that's all for now, thanks everyone for the feedback.
 

JMC

Cast Iron
Joined
Aug 30, 2007
Location
Northern Utah
FYI we are using a $200 solid carbide, coolant through, double margin, ZCC branded drill from Shars.
We are using several others in smaller sizes on another job and so far I'm impressed. Does anyone
Know where these are made? China? SKorea?

Anyway that's all for now, thanks everyone for the feedback.

ZCC is China. The little that I have tried is decent.
 

Orange Vise

Titanium
Joined
Feb 10, 2012
Location
California
My research into cutting force created by Ø5/8 solid carbide or modular drill (using Sandvik website)
indicated <600 pounds cutting force. 5th-Axis website claims maximum clamping force at maximum
torque is 22kN (4945 lbs. force). So the chances of the part being pushed out of vise seem to be slim
to none as long as serrations on jaws don't wear down and tool remains in good condition.
Careful there.

This applies to all vises, including ours.

The two forces you're referring to are not the same. 4945 lbs clamping force simply means there's that much force being applied to the jaws. It doesn't mean the part won't slip if an orthogonal force doesn't exceed 4945 lbs. It's a complicated calculation that involves the static coefficient of friction, the strength of the material, the area of the gripping teeth, etc.

I would venture a guess that the amount of force required to break static friction is substantially less than 4945 lbs. In fact, it's probably much closer to the 600 lbs of axial drilling force you found from the Sandvik site. What this means is that as the drill dulls and the axial forces increase, there might be a point where the part begins to slip. It's hard to say where that is. Serrations help but only to a certain extent. At some point the material will just tear and the part will slip regardless.

This is the reason why dovetailing your material with a positive stop (e.g. dowel pin slot) is the most secure method of holding material, because it doesn't rely strictly on friction to hold workpieces, and instead provides positive engagement in three directions.
 
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CarbideBob

Diamond
Joined
Jan 14, 2007
Location
Flushing/Flint, Michigan
Zhuzhou Cemented Carbide Cutting Tools Co (ZCC) is one of the top level makers of carbide products.
Years back low-medium but have made great gains. Sort of like the Iscar deal or rise to fame.
Poop at first but have made great strides forwards and have the real serious tech in their plants.
I still do not like "Made in China" but these people are very good at it.
 
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Mr.Chipeater

Aluminum
Joined
Apr 20, 2021
Maybe we got a defective 5th-axis vise but at max torque, ours will let parts slip from a stiff breeze (3/8 end mill). Its been extremely disappointing and we run mostly aluminum which should allow for plenty of bite from the serrations. The cause seems to be excessive jaw lift at about 0.010".

I've had to resort to dovetail and pinning everything we run across it to ensure process reliability.
 








 
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