??? ??? the 12 dollar Bosch blades from Lowes work & last pretty darn good over here .

??? ??? animal

On 11/5/2022 3:06 PM, John Vreede wrote:

Hi Mark

You ask what brand blade to use.??

In my experience it doesn't matter much what brand you use so long as it is the right teeth count for the material?and saw.

I've made a bit of a thing about blade performance and have tried?all the blades I can get my hands on, which is by no means all of them, but enough to get a picture: Starrett (US), Lenox (US), Bruel (Germany), Rontgen (Germany) BiChamp (China), iMachinist (China)??Hakkonsen?(Sweden) and Bahco (originally?Swedish but now a Snapon brand made in Belarus).

I've trialled cutting performance (how fast it cuts through a 4"x 5/8" bar and how that changes over 100 repeat cuts), of all the Bimetal blades and there was no statistical difference between them ($7US iMachinist blades off AliExpress to?$35US Bruel imported coil welded in NZ).?

I've never 'worn-out' any of them!

• They've sometimes snapped at the weld (mnfr fault), or
• I've either abused them by cutting hardened?metal (stainless steel work hardens so it becomes uncuttable if you cut too slow which dulls the teeth), or
• I've ripped off teeth because the metal was too thin, or
• The blades snap from metal fatigue from being bent around the too-small diameter of the 4x6's bandwheels. (Run continuously without guides,?all?bimetal blades break after 12-60hrs, it's?very?variable and doesn't seem to relate to blade tension - just the bending back and forth around the wheel.)

When people?say "Buy a good blade" they are mostly talking about?buying a 'Bimetal' blade, which has high speed steel (HSS) tips on a high tensile steel band. There is an intermediate type of blade called Hard-Edge-Hard-Back (which has teeth ground into the same band material as Bimetal blades) and then the 'lowest quality' Hard--Edge-Flex-Back which is generally called a 'Carbon steel' blade. The bimetal blade will cut a greater range of harder metal, but treated properly (proper feed rate with right teeth-in-cut on appropriate hardness material) the others last just as well, better in fact when they're half the price!

The machinery and process to electron beam weld HSS tips on the teeth is not cheap and not many people have it.? At a guess I'd say only a few of the very biggest mnfrs (probably Lenox, Morse, Rontgen Bahco etc) have the gear to do it, and all the others will buy coiled stock from them and grind, weld and trademark it themselves, or get theirs made by the big ones as a 'house brand'.

That said, there is a big difference between the welding?of the different manufacturers and their local?distributors, who make from?coil. This takes into account loop length, alignment of both sides across the joint, annealing of the weld and grinding of the weld-flash at the joint.? The best aligned, loop length and grinding control has been Rontgen - it must be CNC controlled to get them so uniform, however there was something wrong with the annealing?setup that day, and all 3 blades I bought broke at the weld, yet the Rontgen blades I've bought that were welded here in NZ were always OK. The iMachinist blades were very well aligned (better than the Lenox or Starrett) but had far too much ground off the joint - the tips of the teeth were gone on both sides for 3/4" on each side of the weld which made it squeal every time the joint went through the work esp when cutting wood. You can tell how well the grinding has been done by running the joint?in the blade between your thumb and forefinger.? You'll feel the prickle of the sharp points except where they've been ground off.? Done really well, like the CNC controlled Rontgen, there's?less than 1/4" on either side of the weld (1/2" total). The blade should NEVER break at the joint - take it back for a refund or another?blade if it does, no matter?how old.

A bimetal 10-14 TPI vari-pitch, nominal 1/2" wide x 0.025" thick blade is 'the standard'? blade for 4x6's.? It's the blade to have if all you cut is 1/8" thick or thicker steel, set to run at about 7-8lb bow weight. However it is completely the wrong blade to cut aluminium; it will clog the teeth and cut crooked.

A 4 to 8TPI straight pitch carbon blade (only bimetal blades are vari-pitch) will cut aluminum?all day dead straight at 5lb bow weight, much?faster than a 10-14.?

Heat is the enemy of tooth sharpness.? HSS has MUCH greater hot hardness than carbon steel so resists the heat generated by cutting hard steel like high tensile or tool steel, and the heat from cutting stainless steel, which workhardens when cut by a bandsaw (so many teeth at such thin?cut-per- tooth) and is a very poor conductor of heat, so almost all the heat of cutting goes into the teeth which rapidly softens a carbon steel tooth. By comparison aluminium is?an excellent heat conductor and no matter?how fast you feed it, the tooth will never get hot enough to de-temper. At similar TPI, bimetal blades do not cut aluminium any better than carbon steel blades.??

I think the lesson is:?

• The HSS of all bimetal blades is so similar you will not be able to tell the difference, so find a 10-14 blade that is welded properly and stick with that.?
• I'd be?much more inclined to buy a reputable brand name blade for the coarse carbon steel blade that you should also have. They are either a solid blue colour or have the rainbow of induction hardening & tempering colours on teeth and back edge.? Buy a 4 or 6TPI?blade for cutting soft materials (aluminium, brass, wood, plastic etc), as the technology for making carbon steel blades is much more accessible to unsophisticated manufacturers.
• If your saw has hydraulic downfeed control buy a 5-8TPI bimetal blade and use that for everything, just slowing the feed rate as the hardness of the material goes up.

Rgds - jv?

On Sun, Nov 6, 2022 at 2:16 AM mark lacombe <Lacombe1958@...> wrote:

What brand saw blades are you using?

Get

---

From: [email protected] <[email protected]> on behalf of John Vreede <vreededesign@...>
Sent: Friday, November 4, 2022 6:22:19 PM
To: [email protected] <[email protected]>
Subject: Re: [4x6bandsaw] how to square vertical cutting table?

?

My pleasure to be of assistance Steve.

Its a long?time since there's?been any activity on this site and I admit to taking a break from work on the 4x6's.??

I've been helping a friend bring his Mach III Kawasaki back to life.? He bought it new in San Francisco?in 1969 when he was at Stanford, and?won't part with?it in this life. He met his wife because it broke down in Montreal, has road rash on the tops(!) of the handlebars and passenger?grab rail from sliding along the freeway upside down.? So many memories. It runs now and we're attending to cosmetic issues. Great to be part of.

Your?saw?looks like mine, which?just?has a model number - UC115 - and no other distinguishing marks. Taiwanese mnfr from 1987 - jv.

On Sat, Nov 5, 2022 at 10:50 AM steve nicholson <steve@...> wrote:

Well it has only taken 2 years for me to find a good enough reason to make a table for use with the bandsaw in the vertical position AND sort out the table alignment.

Thank you John, I can confirm that fitting a large shim between the top of the guide arm and the frame casting solved the table being square to the blade. I haven't bothered with fitting set screws at the moment, I don't move the lower arm so the shim will work fine for now.

I've attached a photo of the current small table I've made. It is 6mm (1/4") stainless (roughly 100mm x 80mm), the inside edge is angled to the blade and the outside edge is parallel with the blade. I can use the saw in the horizontal and vertical positions with the table in place. I had to grind a small amount off the front of the angled edge to clear the frame in the horizontal position (my wood prototype cleared but may have been warped).

The idea of the small table with the angle on one side, is to allow a larger table with locating guides/rails to slide on and lock into place with the tapper on the small table (still to be tested).

I mentioned the table alignment problem to a friend with a similar bandsaw, he checked his and said his was the same, he is keen to make a small table and fix his alignment now he has seen mine.

So thank you again John Vreede for all you help and knowledge you share on these bandsaws.

Steve

On 23/09/20 22:23, Steve Nicholson wrote:

Thanks for the information John, I'll take another look at the arm and try a packing shim to see how that works for me. Probably be next week before I get a chance to look at it properly.

Thanks again and have a wonderful day all.
Steve

On 23/09/20 4:45 pm, John Vreede wrote:

Arghhh..... Wrong way round!.
Sorry Steve I got up this morning early to write the previous post before going on my regular Wednesday walking group and marked up the sawframe casting to photograph it for you and got it backwards.
I will be putting the setscrews in at the bottom of the casting (where the circle with the dot is in that photo), where you should need to put the grub-screws in at the top, not me.
I moved the bottom of my guide arm out <1mm, I suggest you trial adding about 1.5mm of shim between the arm and the casting at the back of the slot as shown in the photo attached.
If that squares up your table then you can drill & tap
Sorry for the confusion - jv