Work holding ideas for circular saw blades

LivinNstiX · Apr 3, 2021

Long time lurker, first time poster.

Looking for ideas on a work holding fixture to bore out arbor holes in saw blades from 12" diameter up to 46" diameter. So far I use 2"x 2" square tubing bolted to the table as seen in the pictures. I have a quote out for a permanent electromagnet chuck. The arbor holes all start at at-least 1" and I turn them out between 50mm - 150mm depending on the order. I use an offset boring bar setup right now but looking into a few annular cutters to speed up the process.

pavt · Apr 3, 2021

I know you're gonna say I'm crazy, but -- have you considered using either loctite or super glue? That's actually a standard trick nowadays if you can stick it down onto something big and flat enough. Unstick it with a bit of heat from a propane torch or a heat gun. Clean up with acetone and a scrubbie.

Spruewell · Apr 3, 2021

Get a 10” or 12” 3 jaw chuck and make some custom soft jaws with steps in them to accommodate different diameters. Since your parts are thin, the steps can be pretty shallow allowing for a lot of steps

Street · Apr 3, 2021

At the shop i did my time at they used a boring bar with a bush in the table and moved the blade to suit the jig ( centre it ). It was only a flycutter and had to be moved by hand so your setup is more advanced in a mill.. It was a asquith radial arm drill that was used.
I would put two spacers under each side as you will find the tube will bend and only pinch the ends or may even bend the blade.
If the tube bends it won't matter so much with two spacers as they just become pivot points now but support under those points directly so no bending of blade can take place.

The blades we did where wood saw blades very large in diameter, your only doing concrete saw blades of moderate diameter so looks like your going reasonably well.

on edit you to have resorted to doing it in a radial arm drill......

LivinNstiX · Apr 4, 2021

Pavt- good idea, with 3 debatable issues; dry time, some blades are brand new covered in anti-rust oil, and some blades already have segments not allowing to sit true flat.

Spruewell- a great idea if I can find one cheap enough. How would I hold the blades? I don’t think a 12” chuck could hold a 40” blade.

Street- I’d like to know more about the jig you mention. I’m doing the exact same thing you describe, I have a +.002” -.000” tolerance is why I use an offset boring bar. I open the arbor hole .050” at a time. I WAS using a radial arm drill but it needs bearings and the chatter was getting bad. Using the milling machine for now with increased rigidity.

(Edits were to reply to each person, thank you all)

Limy Sami · Apr 4, 2021

2 discs / washers of marine ply, (3/4'' + T) .......with OD clearing the teeth, ID large enough to clear the bore, one on the m/c table, saw blade then 2nd on top and some strap clamps like you have ..........will give a better support and damp vibrations etc etc

LivinNstiX · Apr 4, 2021

Limy- much easier than making one out of steel or aluminum and very portable. If I notch the plywood to allow my t-bolts to slide in and out to accommodate different sizes.

Limy Sami · Apr 4, 2021

LivinNstiX said:
Limy- much easier than making one out of steel or aluminum and very portable. If I notch the plywood to allow my t-bolts to slide in and out to accommodate different sizes.

You got it

.......and marine ply (even the very best resin bonded trailer decking stuff) is much cheaper than any metal, ........and will grip the saw blades better than metal

Thinking about it I'd keep away from the super duper ply as above the ''ordinary will have better vibe damping, ................while you're at the lumber yard, also grab some say 2x3s or 4s of White Oak (or simlar) for clamping bars, again lighter and better damping

Bill D · Apr 5, 2021

Drill two holes equal distance from the center all three in a line. Through bolt through those holes. Make them a standard distance apart and reduce setup time.
Bill D

Talinthon · Apr 5, 2021

pavt said:
I know you're gonna say I'm crazy, but -- have you considered using either loctite or super glue? That's actually a standard trick nowadays if you can stick it down onto something big and flat enough. Unstick it with a bit of heat from a propane torch or a heat gun. Clean up with acetone and a scrubbie.

Heating the body of the blades isn't a good idea as the heat may cause the steel to pull when it cools causing a high spot and possibly changing the tension in that part of the blade.

mhajicek · Apr 5, 2021

Mag chuck?

Superbowl · Apr 5, 2021

Two piece vise with soft contoured jaws and a sacrifical plate under the blade.

Street · Apr 6, 2021

The jig was just a bar with morse taper one end and a straight bar with holes for cutter and grubscrews to hold the tool in place. the bar had a corresponding bronze bush in the table and you just lined the bar up with it and it supported the end. Jammed the bar in the morse taper to hold it in place.
Just like you would do in a overarm mill except vertical now.

Tool was moved out with a dial indicator to get size the first cut was the test size.
Nothing particularly special at all ...a boring head is a much better way to hold a tolerance except it does not have support on the end.

just another way of doing it. Yep i would not heat the blades at all they are bound to have stresses in them and releasing stresses will warp them all over the place.
Wood saw blades is what we did just large ones, only the spigot bore was changed that the extent we did work on them the saw shop did all the other work to them.

atomarc · Apr 6, 2021

I have bored hundreds of saws although none in the 40" range. I have a fixture that I'll snap a picture of tomorrow and post. It served me well for many years and may give you some ideas. It appears all your plates are 'pre-toothed', so that does make a difference. The saws I did were always finished, other than the eye.

I used a Gamet automatic boring head which sped up the process considerably...saw plate is tough stuff.

Stuart

dian · Apr 6, 2021

get 2 or 3 door lock magnets off ebay.

Ray Behner · Apr 6, 2021

I do piles of metal cutting blades (44Rc) already toothed. From 50cm to 124cm. Hate those big heavy rascals. Usually opening up bores and putting in lug pin holes. I've made up arbors to fit the hole size. Put it in a collet in the mill. Stack the blades on a piece of hyd. tube machined to about 1" high. Bring arbor down into blades. Now they're centered. Two parallels at base ring area. Two long parallels with cross bars to clamp to table.

Bill D · Apr 6, 2021

At first read I was thinking rubber hydraulic hose. Now I think you mean solid metal tube.
Bill D

atomarc · Apr 6, 2021

I promised pictures of how I addressed the question, and for what it's worth, here they are.

The side platforms slide in and out to accommodate different saws while the hole in the middle allows the boring bar to clear the saw thickness. Small ledges on the two side platforms allow them to clear the carbide teeth without busting them off when clamping the plate to the jig.

Sort of crude, but it did the job many times over.

Stuart

boslab · Apr 6, 2021

As it’s a bore needing the work how would 3 vacuum pad ( or 2 ) supports sound?
I recently tried a festo vac vice, there was no way I was pulling the sheet off it, could not even slide it or rotate it, the bench was moving, I’m not implying a festo one as the price boarders on nausea, ( I need a domino jointer for a pile of doors, no change from £1000!) think the Morticer is getting overhaul 15/16 chisel my arse, how dull
Mark

Garwood · Apr 6, 2021

I've done many using a CNC mill.

I prefer a few light peripheral clamps with the blade on hardwood/thin cardboard. I use carbide endmills with airblast.

Most of what I've done is cutting the wormdrive diamond into large metal cutting blades.

Work holding ideas for circular saw blades

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