Work holding for large irregular shaped items (Intake manifold) on smaller mill.

Dave94Lightning · Mar 25, 2021

Hi. I'm looking for advice on the correct way to clamp a large intake onto a relatively small T slot mill table. The shape makes it difficult to locate clamps sufficiently and the T slots are occluded by the size of the workpiece. Do they make T slot extensions or "outriggers" that would allow me to place some clamps off the mill table? I would prefer not to build a specific fixture just for this process because the intake will have to be flipped and rotated for other operations. You can see my make shift welding clamp holding down the rear. Thanks in advance.

David

boslab · Mar 26, 2021

Get or make a fixture plate to suit, bit of work but always useful, need a fixing, pop a hole and tap
Mark

thermite · Mar 26, 2021

Dave94Lightning said:
Hi. I'm looking for advice on the correct way to clamp a large intake onto a relatively small T slot mill table. The shape makes it difficult to locate clamps sufficiently and the T slots are occluded by the size of the workpiece. Do they make T slot extensions or "outriggers" that would allow me to place some clamps off the mill table? I would prefer not to build a specific fixture just for this process because the intake will have to be flipped and rotated for other operations. You can see my make shift welding clamp holding down the rear. Thanks in advance.

David

View attachment 317408

Long ago.. one of the early 90-degree GMC V6 into a Jeep Cherokee.. or so Advance Adapter told me it was the first they had been asked to make parts to support..

They shipped me a pair of mild steel plates burnt and drilled to bolt to the block. I then built the header shape I wanted onto them, sent it back. They then bent tube and welded up the manifold to clear all the stuff my shapes had cleared.

Fit perfectly.

The fixture you need can start in a similar manner. Plates that emulate the block it will attach to.

Same bolts. Same stresses.

That's one way as need not break much of a budget.

Why try to clamp, shim, wedge, jack it anywhere BUT ... where it will naturally be attached and fastened when put into actual SERVICE? Unwanted damage or distortion can happen?

I'm sure there are more ways.

Folks have been casting s**t for more than just a day or three?

Winterfalke · Mar 26, 2021

It looks like the machine has a horizontal head, if it were me I would make use of it since it's likely to be significantly more rigid. I would get my hands on a large angle plate or jig block with t-slots and bolt the head up to that. If you can swing the head out of the way you can go rather large, and most your weight is directly over the table.

Limy Sami · Mar 26, 2021

Swivel angle plate is what I've used for years ......like these?? swivel angle plate - Google Search

You can always fix a bigger plate to it to carry that sort of job.

Clive603 · Mar 26, 2021

For that sort of work I have one of the tilting milling table of the sort where the work table slides round a half circle base .

I always feel that bolts clamping the table unit down to a solid carrier are more positive and secure than a simple swivel. Especially as said swivel of necessity has various clearances so that rotation is possible giving scope for unwanted movement. It is said that affordable versions are often not as well made as one would ideally like with excess clearances and inadequate attention to keeping things parallel and perpendicular where required. Correcting economy range errors to appropriate levels of precision is more involved than it appears at first sight.

At least the half circle base variety can be adequately corrected by resorting to the shaper drivers standard trick of machining the table in situ.

It appears that many makers of these devices now fit a screw adjuster to set the angle. I don't see any great advantage. More a source of considerable frustration unless the screw so is well fitted so as to have almost no backlash. Complicates the design and uses money better spent on getting the basics right. As the prices are generally economy seems yet another case of catalogue appeal trumping workshop appeal.

Mine is a high quality UK made one, probably nearly as old as I am, very basic just push to set and no scales. But any alignment errors seem to be smaller than I can reliably measure. So I just mount it up and get to work.

Clive

crossthread · Mar 26, 2021

As Thermite said....clamp it any way you can. I have had to do this on many occasions and yes it can be a pain in the rear and time consuming. If you can limit your cuts you put a lot less strain on the whole setup and you can get away with a less then perfect clamping system. Step back and take a look at where it really does need to be clamped and then work that out and move on to the next step. You may have to turn some posts, make some shims, set up some screw jacks etc. I have flycut quite a few small engine heads and they can be challenging to set up.

thermite · Mar 26, 2021

crossthread said:
As Thermite said....clamp it any way you can.

Well. no.. I said clamp it the way it is meant to be MOUNTED when put into end-use service.

Whomever designed the casting will have insured that the mounting flanges are suited to carry the stress OF mounting - thermal stress and vibration included.
Else it fails in-use. Early.

Every OTHER "feature" on the whole rig has some OTHER design goal.

Thin, light, curved just-so, clearanced for some other component.. optimized for gas/vapour flow.. tuned as to length.. etc, among the more obvious for induction manifolds.

Make use of what is already there!

EVEN if.. it is the mounting flanges themselves that need that first machining OP? That's where the "meat" is.

Find or make a way to use it.

ELSE risk ruination of the fragile areas NOT meant for "mounting" a damned thing but outside air NOT mean to go into the 'bustion chamberpot. Some damned thin sections "happen" on many a light-alloy manifold.

"In due course".. one has a fit-alike fixture for each of SEVERAL blocks.

But ANY manifold made to fit said block, old, now, or future will bolt-up.

IOW that type of jig has enduring value. Worth taking the time to fab it. It just isn't that hard.

donie · Mar 26, 2021

Come on termite, show a photo, make everyone go crazy and spread outrageous lies!
your addiction to posting nonsense on this forum everyday 24-7, is getting the better of you.

GregSY · Mar 26, 2021

I've milled a lot of intakes. It's always a task getting them set up...but that's the price I pay for using a mill rather than a purpose-built intake milling machine. And, I've never made a fixture because I don't mill enough intakes to warrant that.

If you're not willing to spend some time making a fixture....then you'll suffer accordingly. Based on that professional banner hanging on the wall, you should invest (at least) in the time and effort it takes to make a good fixture.

One tip....I've sometimes run a tap down the intake mounting holes, which are normally smooth-bored. That allowed me to thread in a stud/nut that allowed me to secure the intake from below without anything getting in the way of the intake face I was trying to mill.

Dave94Lightning · Mar 26, 2021

Thank you all for lots of good info. I understand the benefit of using the original mounting points to secure the intake as it would be the most robust. I have seen those swivel angle tilt tables that would make it easier to mount, however this mill is pretty small and the total height of that swivel table plus the intake would exceed the capacity of the mill. In this operation I was trying to mill down the numerous casting bosses on the underside of the intake in order to create some space for a sneaky nitrous system that I'll be plumbing under the intake.

thermite · Mar 26, 2021

Dave94Lightning said:
Thank you all for lots of good info. I understand the benefit of using the original mounting points to secure the intake as it would be the most robust. I have seen those swivel angle tilt tables that would make it easier to mount, however this mill is pretty small and the total height of that swivel table plus the intake would exceed the capacity of the mill. In this operation I was trying to mill down the numerous casting bosses on the underside of the intake in order to create some space for a sneaky nitrous system that I'll be plumbing under the intake.

View attachment 317450

"Sneaky" took a different route in my mis-spent youth. Mate of mine fitted an early '50's Buick "Roadhamster" V8 into an old "Turret top" Ivory and powder-blue Studefreaker "President" 4.dr. Hadda torch-cut the firewall, bread-knife the foam in the front bench seat so he could shift.

Quite the "sleeper".. until Packard dropped their V8 fire-truck engine into a Studefreaker "Hawk" as an option.

Heavy bugger! Made a MOPAR Hemi look like an Ariel motorsickle engine by comparison.

TANSTAAFL, so ISTR it required machinery skates under the frame to deal with bumps in the road, and a pair of bob-tail Peterbilt's with cables as outriders to depart from a straight line?

You'd have to know what outright shite they considered a "tire" back in the day?

Or didn't even try to do..

Blow-out resistant high-speed tires

Damned Hot-Rodders!

donie · Mar 26, 2021

termite, the addiction is getting worse, the rambling on and on, and trolling is getting harder! The weight of the lies, and the lies to cover the lies, that you were a jewelry store clerk, not a machinist in 1959.....

rat_stomper · Mar 26, 2021

I like that idea, how big of a sniff are you planning on?

tlowe · Mar 26, 2021

Not sure how many you are doing, but I use one of these fixtures. It will do heads, intakes, carbs ect. CPM Head Fixture Info

Dave94Lightning · Mar 26, 2021

Tbartoletta said:
I like that idea, how big of a sniff are you planning on?

200 on that kit.

Dave94Lightning · Mar 26, 2021

Yes I really like that fixture set up but I don't do enough Intake or head work to justify it for now. Maybe when I get a real mill and get better at it I can buy or build a set up like that.

thermite · Mar 26, 2021

Dave94Lightning said:
Yes I really like that fixture set up but I don't do enough Intake or head work to justify it for now. Maybe when I get a real mill and get better at it I can buy or build a set up like that.

You do not need the whole dam' UNIVERSE. yet. Or maybe NEVER?

All you need for NOW - the one manifold - is a few bucks worth of ignorant A36 from the local structural steel building supply ... a few welds done for yah. and the mill, drills, taps, etc. you already OWN to clean-it up and "make it RIGHT". Old timer could prolly heat-bend "Ell" cutoffs, shim heel or toe, hit the angle well enough and pick-up off a Tee-slot or drilled flat plate.

Not as if you were cutting keyway in a locomotive driver wheel, is it?

How much is your time worth trying to make a common TECO 'starter set' of general-purpose clamping goods fit what it don't fit?

Wasting time on "don't fits" is one of the ways to NEVER GET "a real mill".

Run what you got!

To "bootstrap" it's own self, when need be. "Wishing" is gen'rally USELESS.

kenton · Mar 26, 2021

tlowe said:
Not sure how many you are doing, but I use one of these fixtures. It will do heads, intakes, carbs ect. CPM Head Fixture Info

My brother in law borrowed/stole a chunk of 8620TGP from me to make a fixture very similar to that. It did seem to work pretty well.

Maybe I shouldn't have given him as much credit as I did. :crazy:

thermite · Mar 26, 2021

kenton said:
My brother in law borrowed/stole a chunk of 8620TGP from me to make a fixture very similar to that. It did seem to work pretty well.

Maybe I shouldn't have given him as much credit as I did.

They still make Ordnance Steel. My favrit' playtoy for the relative general-purposeness of it, vs 4XXX!

Order-up the replacement for it! Billing the miscreant for it optional!

:popcorn:

Work holding for large irregular shaped items (Intake manifold) on smaller mill.

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