Routing question.

[the great waldo]

A guitar body. Hard (brittle) coating. I need to cut out a recess. Routing the obvious tool choice.
How to protect the coating (shiny black.. polyurethene perhaps?) from chipping at the edge.
New cutter to be used.
Any suggestions please?

I assume it's a polyester finish. First question what kind of pickup Guitar or bass ? Important to know for the corner radius if it's a Jazz bass pickup. A guitar humbucker or strat you can use 8mm cutters Jazz bass 6 mm. Make yourself a template from acrylic or mdf, double sided tape to hold it onto the body. A down spiral cutter will give you the best finish although you can get away with a sharp normal cutter. Hog out the main part of the cavity leaving 1.or2 mm near the template and then do the finishing cut's If you have a 6mm 1/4 " cutter you can use the cutter shaft edge to ride along the template (you should'nt dwell to long on one spot as you can melt / burn the template. (make sure to plunge the router deep enough that the cutting edge is below the template otherwise you'll bugg er up the template! Practice on a piece of spare wood to get a feel of the cut. Be carefull removing the template twisting it side to side instead of pulling up (could pull of some paint, unlikely but possible) After you've done the routing run a little thin super glue into the edges wher the paint is cut to help reducing chances ot he edges chipping.) Avoid the tendency to make the template a tight fit as a little space to insert the pickup will reduce fitting problems. Good luck.
Cheers
Andrew

 

[BillK]

What's the guitar? I've done this often enough and never had a problem with paint. I think more about the endgrain passes than the paint itself chipping, smaller cutter and good speed. Chisel out to lessen routing. Etc.
If it's not having any kind of surround or scratchplate over it you could be a bit cautious and sneak up by using an oversize bearing at first, or binding tape layered inside a template edge.

Depending what it is you're more likely to pull up paint with excess d/s tape than have a problem cutting a paint film. Sometimes the adhesion of a colour coat to a hard sealer can be pretty weak. If I'm suspecting any problems or if it's a vintage guitar then I make an big old oversized template that can be clamped, body & template to the bench at the same time and clamps well out of the way.

Rectangle shapes are easy to template up but if you need something feel free to shout, I might have it, this is my day job so I'm around most times.

 

[pe2dave]

What's the guitar? I've done this often enough and never had a problem with paint. I think more about the endgrain passes than the paint itself chipping, smaller cutter and good speed. Chisel out to lessen routing. Etc.
If it's not having any kind of surround or scratchplate over it you could be a bit cautious and sneak up by using an oversize bearing at first, or binding tape layered inside a template edge.

Depending what it is you're more likely to pull up paint with excess d/s tape than have a problem cutting a paint film. Sometimes the adhesion of a colour coat to a hard sealer can be pretty weak. If I'm suspecting any problems or if it's a vintage guitar then I make an big old oversized template that can be clamped, body & template to the bench at the same time and clamps well out of the way.

Rectangle shapes are easy to template up but if you need something feel free to shout, I might have it, this is my day job so I'm around most times.

Thanks Bill
I don't know what guitar it is, I'm assisting a friend who doesn't have a router.
Agree on final 'cut' being with other than router.
I won't be using ds tape
Thanks for the offer. Until the job is ready for me to route it, I don't have more information.
The brittle paint was the issue that was brought to my attention.

I'll get back to you with further detail when I have it..

 

[Stevekane]

Sounds idea Steve. Can you remember the seller please?

And I'd better express my ignorance. 40 years using a router... no idea what the difference is (in use / purpose) upcut vs downcut spiral?

Edit:
(Apart from the super clean apron / workshop) seems to express the logic. Clearly downcut to keep the surface 'clean'.

Hello Dave, here is the lot I bought from, a chinese outfit but shipped from the uk so regular shipping times, lets see if I can paste this,,, hq-toolshome | eBay Stores
Well that looks promising,,given that your trying to avoid tearing up the top edge perhaps a downcut might be best,,,but I should say that Im far from well versed in these things. Btw my upcut 12.7mm bit was around £3 when I bought it last year,,,oh and this might be obvious but check out the shank dia for the size of bit you want,,I think many of these things are “end mills” rather than straightforward router bits and I beleive our engineering friends have access to whole sets of collets?
Steve.

 

[the great waldo]

Hi Dave
As a guitar maker I think it's going to be cheaper / less hassle to take the guitar to a good guitar maker (electric guitar maker) who has the right tools and templates on hand. In the long run costing in a new cutter and your time it wouldn't be worth it doing it yourself. If you do want to do it then you'll have to make a template one of the cutters here Template Profilers - Trimmer & Profiler Cutters - Professional Router Cutters - Router Cutter Ranges - Products should cover your needs.
Cheers
Andrew

 

[baldkev]

As above, it might not cost too much going to a luthier and takes the risk out of your hands..... or a cnc company, who will no doubt already have good quality cutters.

Personally I'd make myself a template, use a top bearing cutter and start in the middle of the aperture to see how the cutter / finish copes before going to the edge....

 

[JobandKnock]

...but check out the shank dia for the size of bit you want,,I think many of these things are “end mills” rather than straightforward router bits and I beleive our engineering friends have access to whole sets of collets?

Dave's router is an Elu MOF177, I believe, and that router uses a German engineering collet (can't remember the model, though). Elu and deWalt have offered collets for this router in 6mm (EU), 6.35mm-1/4in (UK & USA), 8mm (EU & UK), 9.53mm-3/8in (UK & USA), 10mm (EU), 12mm (EU) and 12.7mm-1/2in (UK & USA) mm. Trend offer the same range. I believe that DW dropped the 3/8in collet a few years back (as did Trend - probably because they source from DW, or possible Perles who assemble them these days), but the rest of them are still available, though not necessarily all sizes in all markets. In the UK Trend sell the 1/4in, 8mm and 1/2in in the UK - Sautershop list the 8 and 12mm in their on line shop

 

[TRITON]

Take note not all spiral cutters have plunge cut tips.

 

[BillK]

Thanks Bill
I don't know what guitar it is, I'm assisting a friend who doesn't have a router.
Agree on final 'cut' being with other than router.
I won't be using ds tape
Thanks for the offer. Until the job is ready for me to route it, I don't have more information.
The brittle paint was the issue that was brought to my attention.

I'll get back to you with further detail when I have it..

Hi Dave, no worries, I do the actual cutout with a router, but first chisel as much as poss especially the endgrain sides first. Usual stuff.
If the paint's at all well put on, wood tearout's more likely than paint problems, but so far haven't had any problems, and never had to do anything much special for this job yet, no special cutters or anything else much.
As you're fairly close and you do want a template I've got, you may as well come & do it here while I sip a brew. Won't take very long at all to do.

 

[pe2dave]

Hi Dave, no worries, I do the actual cutout with a router, but first chisel as much as poss especially the endgrain sides first. Usual stuff.
If the paint's at all well put on, wood tearout's more likely than paint problems, but so far haven't had any problems, and never had to do anything much special for this job yet, no special cutters or anything else much.
As you're fairly close and you do want a template I've got, you may as well come & do it here while I sip a brew. Won't take very long at all to do.

Very kind.
Curious why you use a chisel first?
Endgrain? (Guess) it wouldn't be endgrain mid body?
Pic attached.

 

[BillK]

Just to chop out excess to be routing out less, less chippy although recesses are pretty well-behaved and I haven't had any chipping out yet paint or no. The long sides of the pickup recesses are endgrain faces, quick pic here not that you'd need it but should show a recess face.

If it saves buying a cutter or template faff etc just drop down, will only take a few mins

 

[Stevekane]

Dave's router is an Elu MOF177, I believe, and that router uses a German engineering collet (can't remember the model, though). Elu and deWalt have offered collets for this router in 6mm (EU), 6.35mm-1/4in (UK & USA), 8mm (EU & UK), 9.53mm-3/8in (UK & USA), 10mm (EU), 12mm (EU) and 12.7mm-1/2in (UK & USA) mm. Trend offer the same range. I believe that DW dropped the 3/8in collet a few years back (as did Trend - probably because they source from DW, or possible Perles who assemble them these days), but the rest of them are still available, though not necessarily all sizes in all markets. In the UK Trend sell the 1/4in, 8mm and 1/2in in the UK - Sautershop list the 8 and 12mm in their on line shop

Indeed, there are a number of router bit collet sizes but I think ( though I wouldnt swear to it) that some of the end mills come in very odd shank sizes related to the cutter dia, so best to double check if going for one of these.
Steve

 

[Stevekane]

Take note not all spiral cutters have plunge cut tips.

Yes quite correct, however I was using a 12.7mm upcut spiral bit that was not made for plungeing, it had cutters around the edge but a solid centre and in softwood I found that i could easily plunge providing I had drilled just one hole, plunging down the sidebof the hole and working along and then sweeping the slot to finish off, I guess it could be similer in hardwood as it was the bit cutting and it didnt need forceing.
Steve