Making your own spindle moulder cutters

[jfc]

I've tried this before with very bad results so just how do you make them and get everything in the right place .
I assume you buy the blanks or rebate cutters for a standard pinned block and need a grinding wheel which i have but what grinding disks do i need ? Do i blank off the limiter with a short rebate limiter or grind limiters aswell ?

[jfc]

I have a set of shorter rebate cutters that do the job of blanking off the limiter part of the block but still keep it wedged on the cutters . Not legal to do this
Sometimes if its a small moulding or run then £45 to have a set of just cutters is better than £90 for both and i'm happy doing it this way .

[mrgrimsdale]

jfc said:

I've tried this before with very bad results so just how do you make them and get everything in the right place .
I assume you buy the blanks or rebate cutters for a standard pinned block and need a grinding wheel which i have but what grinding disks do i need ? Do i blank off the limiter with a short rebate limiter or grind limiters aswell ?

I've got my own way sorted out - no doubt others do it differently.
Buy 4mm HSS blanks. Spray on primer on one side to take pencil marks. Draw on profile from sample. Rough out with angle grinder. Work to the line with 6" bench grinder 4 wheels - one square one round profile for 1/2" and 1/4" white grit wheels - you shape them yourself with a dressing tool.
The shaping is all square not yet backed off, but keep offering up to sample to check. Then back off the bevel to make a cutting edge. Then the clever bit - it cuts at an angle so you have to deepen all the hollows by a gnats, offering up to sample again, but held at the cutting angle as near as you can judge.
This doesn't sound too accurate but it produces better results than a copy machine believe it or not. The critical thing is to keep offering up and fine adjusting until there is a perfect visual fit
Make limiter to match roughly - just has to be 1mm or more, smaller than the cutter.
Make cutters in pairs, but assume that one is there for balance only, so it doesn't need to be so accurate as it doesn't cut - it's set back a bit.
Cost less than the cheapest router cutter but out performs it by miles!
It's very similar to what you'd have to do to make a moulding plane except you don't need the wood bits so it's a lot easier - and there is a real sense of going full circle and getting back to trad basics.

cheers
Jacob

[Scrit]

jfc said:

I've tried this before with very bad results so just how do you make them and get everything in the right place? I assume you buy the blanks or rebate cutters for a standard pinned block and need a grinding wheel which I have but what grinding disks do I need ? Do I blank off the limiter with a short rebate limiter or grind limiters as well ?

1. To do it right on a limiter block with pinned or serrated cutters requires a copy profile grinder. If you're lucky you might pick up a second-hand one which has no limiter capability for as little as £2k (£4k to £12k new)

2. You start from unground blanks which are often longer than rebate cutters

3. The wheels are specifically sold for profile grinding by firms like Norton, however I've always been forced to buy in tens as nobody stocks them other than a few specialised dealers (e.g. Scott & Sargent) or grinding machinery manufacturers (e.g. Autool at Sabden near Blackburn, Lancashire - the sole UK manufacturer of woodworking industry grinders). Typically the discs used are 4mm thick and come in square-edge, round edge and taper edge versions and several grits. They are fragile (as they are so thin) and are best used with a coolant system to help avoid burning the blanks

4. You should grind limiters as well and these should describe a circle with radius no more than 1.1mm less than the main cutters. If you aren't using limiters and have an accident you may find yourself (as a tradesman) uninsured. or at best only partly covered..... The choice is yours.

Frankly grinding 4-cutter sets (2 cutters + 2 limiters) in the absence of a profile grinder is simply not practically feasible for most people. You need to be able to make a projection which converts the profile to be cut into a cutter profile - and as the cutter has an attack angle it means that a round shape in the finished goods looks somewhat elongated in the cutter. You then need to be able to grind the profile, complete with back clearance and then grind the side clearances as well. Too shallow an angle and the cutter doesn't cut cleanly and overheats, too deep and angle and the edge wears quickly.

Scrit

[Scrit]

mrgrimsdale said:

This doesn't sound too accurate but it produces better results than a copy machine believe it or not.

Having used and owned Wadklin and Autool profile grinders in the past I'd refute that one, Jacob. The quality of knife is always dependent on the skill of tha man making it and the template, however template grinders have the ability to reproduce multiple copies of knives at any time in the future which will exactly match the original knives. They're also quick (3 to 4 minutes per knife in many cases)

Let's just say on this one we'll agree to differ ;D

Scrit

[jfc]

I just wanna run off the odd moulding without it costing me £90 a time not supply the world with mouldings

[mrgrimsdale]

scrit said:

mrgrimsdale said:

This doesn't sound too accurate but it produces better results than a copy machine believe it or not.

Having used and owned Wadklin and Autool profile grinders in the past I'd refute that one, Jacob. The quality of knife is always dependent on the skill of tha man making it and the template, however template grinders have the ability to reproduce multiple copies of knives at any time in the future which will exactly match the original knives. They're also quick (3 to 4 minutes per knife in many cases)

Let's just say on this one we'll agree to differ ;D

Scrit

I've done it both ways - sent off samples to machine shops too. Hand and eye is more accurate, mainly because there are fewer intermediate steps such as making a template, and fewer intervening bits of machinery - any bit of which may be less than perfectly adjusted. Also by hand you are checking at intervals against the original. If the sample is at all faulty such as having rounded off corners you can improve on this so that your new work is closer to the original than the sample itself i.e. better than perfect!
Yes its 4 pieces but only one of them is cutting. Half a days work though - I'd only do it for accuracy, otherwise I'd get it copied by machine if not too bothered - or perhaps fettle a machine made one to make it perfect, though I've never tried that - there's an idea.

cheers
Jacob

[jfc]

Any links to the discs and grinders (not the angle grinder ;D ) that are used to do this ?

[Scrit]

mrgrimsdale said:

I've done it both ways - sent off samples to machine shops too. Hand and eye is more accurate, mainly because there are fewer intermediate steps such as making a template, and fewer intervening bits of machinery - any bit of which may be less than perfectly adjusted.

Well, I've owned both Autool (PR100X) and Wadkin (NX230) template profile grinders and from experience I'd say it takes one hell of a hand grinder to get anywhere near the consistency and repeatability of a half-decent grinder. Yes, you do need to touch-up the inside corners with a file, but that would be the case no matter what. My own experience leads me to say it will take 20 or so minutes to make the "average" 50mm profile, and a further hour to grind two knives and matching limiters with a further 10 minutes to clean-up. And in that case both cutters will be doing some work, be balanced and will have the appropriate back and side clearances.

Scrit

[thatsnotafestool]

senior said:

The limiters should be the same shape as the cutter but 1mm smaller all round, otherwise the limiter is pointless. its designed to only take a 1mm slice of your finger at a time

Ummm...that's 1mm per revolution. My spindle moulder runs at 8500 rpm...I'm only 182cm.

[andy]

thatsnotafestool said:

Ummm...that's 1mm per revolution. My spindle moulder runs at 8500 rpm...I'm only 182cm.

2 sets of blades and limiters per cutter therefore 2mm per revolution ;D

Down to size in half the time ;D

[Scrit]

In fact the "backwards" angle of the limiter will tend to "brush" your hand out of the cutterblock....... so with any amount of luck you'll just end up with very bruised knuckles

Scrit