Custom router bit

I need to make (or have made) a custom router bit. The groove I need to mak e is a truncated V 15/16" wide at the top, 3/8" wide at the bottom and 1/4"
deep. The dimensions aren't super critical, but closer is better.
I do NOT have a real tool grinder, and HF seems to have discontinued theirs . I also don't (as will become apparent) have more than a very little bit o f experience grinding tool bits. I DO have 1x30 and 4x36 belt sanders, a se t of 5C collets and a square collet block.
I'm thinking that I could lay out the shape on a blank, hold it in the coll
e line. Then grind the flat end and its cutting edges.
Question 1: Does the above sound reasonable?
I have found a source for HS blanks http://goo.gl/13G1cD but a) they're not at all cheap and b) they have a half-inch shank and I have a 1/4" router. I'm not opposed to a new router, but only if I really need it.
Question 2: Is there any reason I couldn't start out with a 15/16" spade bit as my bl ank? Even the most expensive spade bit is going to be less expensive than t hat router bit blank. Is there something about a spade bit that would make it totally unsuitable for this?
Question 3: should I just job this out? If so, is there anyone here who would want to do it? How much should I expect to pay?
Thanks for the input.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I need to make (or have made) a custom router bit. The groove I need to make is a truncated V 15/16" wide at the top, 3/8" wide at the bottom and 1/4" deep. The dimensions aren't super critical, but closer is better.
I do NOT have a real tool grinder, and HF seems to have discontinued theirs. I also don't (as will become apparent) have more than a very little bit of experience grinding tool bits. I DO have 1x30 and 4x36 belt sanders, a set of 5C collets and a square collet block.
I'm thinking that I could lay out the shape on a blank, hold it in the
grind to the line. Then grind the flat end and its cutting edges.
Question 1: Does the above sound reasonable?
I have found a source for HS blanks http://goo.gl/13G1cD but a) they're not at all cheap and b) they have a half-inch shank and I have a 1/4" router. I'm not opposed to a new router, but only if I really need it.
Question 2: Is there any reason I couldn't start out with a 15/16" spade bit as my blank? Even the most expensive spade bit is going to be less expensive than that router bit blank. Is there something about a spade bit that would make it totally unsuitable for this?
Question 3: should I just job this out? If so, is there anyone here who would want to do it? How much should I expect to pay?
Thanks for the input.
===You didn't mention the material it must cut. Soft wood doesn't need HSS tools.
If the groove is straight with open ends there are other ways to cut it. -jsw
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 7/21/2014 4:13 PM, rangerssuck wrote:

How much of this groove do you need to make? One time? Or production?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Bob Engelhardt wrote:

and use it to angle the sides of a 3/8" groove .
--
Snag



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Terry Coombs" <



Snag, are you saying do it in two passes? I like that idea as it will solve the chip interference action when done in one pass.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Phil Kangas wrote:



I spent 20 years in cabinet shops , often with a very limited tooling budget . The boss liked it when I could make two $12 tooling items do the job of a single $165 tool ... To answer your question more directly , yes , 2 tools and a total of 3 passes - groove , near side then far side on the return pass . This approach will need fences/guides and a very accurate setup .
--
Snag



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:



+1
--
"When the people fear their government, there is tyranny; when the
government fears the people, there is liberty."
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload


I've made a few different specialty cutters for one off jobs on my CNC mill by cutting a piece out of plane old 1018 sharpening it, case hardening, and the resharpening. I've also made a few cutters that didn't have to hold up at all by scribing a piece, and free hand grinding back and forth between the bench grinder and the belt sander.
So what are you cutting? How much of it are you cutting? Will you need to rinse and repeat? Sine you specifically said router, then I am guessing wood, but I do use a router for cutting aluminum and brass sometimes too.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Please make 2. I need one also. I need mine for cutting the "belt" groove in perimeter of a 30" diameter spinning wheel's driving wheel. I have been looking for exactly that profile for a long time.
Pete Stanaitis ---------------
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I need to make (or have made) a custom router bit. The groove I need to make is a truncated V 15/16" wide at the top, 3/8" wide at the bottom and 1/4" deep. The dimensions aren't super critical, but closer is better.
I do NOT have a real tool grinder, and HF seems to have discontinued theirs. I also don't (as will become apparent) have more than a very little bit of experience grinding tool bits. I DO have 1x30 and 4x36 belt sanders, a set of 5C collets and a square collet block.
I'm thinking that I could lay out the shape on a blank, hold it in the
grind to the line. Then grind the flat end and its cutting edges.
Question 1: Does the above sound reasonable?
I have found a source for HS blanks http://goo.gl/13G1cD but a) they're not at all cheap and b) they have a half-inch shank and I have a 1/4" router. I'm not opposed to a new router, but only if I really need it.
Question 2: Is there any reason I couldn't start out with a 15/16" spade bit as my blank? Even the most expensive spade bit is going to be less expensive than that router bit blank. Is there something about a spade bit that would make it totally unsuitable for this?
Question 3: should I just job this out? If so, is there anyone here who would want to do it? How much should I expect to pay?
Thanks for the input.
=Probably I would sacrifice an old center drill; spade bits typically only have a 1/4 diameter shank and so they'll bend very easily if subjected to much side loading.
Offhand grinding of this sort of tooling is made quite a bit easier if you use a single flute design.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
PrecisionmachinisT wrote:


Won't a single flute cutter run into balance problems at 20,000 plus RPM's ?
--
Snag



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:


It might at that. I have used single flute cutters at high speeds but not 20,000 RPM. It would not be hard though to grind away material on the other side of the cutter. This would limit how many times the cutter could be resharpened but not by much. Eric
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload


the

RPM's ?

Probably not enough to be a problem with a 1/2in diameter tool, especially if the router motor is mounted to a table.
However, that's not to say that the gullet on the opposite side could not be gashed away to effect a better balance if desired.....it's just that without proper fixturing, it's a hell of a lot easier to grind a single lip that it is to grind two of them and have both cutting edges end up being reasonably concentric to the rotational centerline.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Monday, July 21, 2014 8:13:23 PM UTC, rangerssuck wrote:

ake is a truncated V 15/16" wide at the top, 3/8" wide at the bottom and 1/ 4" deep. The dimensions aren't super critical, but closer is better.

Would you settle for a standard router bit that makes the groove?
I looked at the router bits that I have and found that I think is for trimm ing formica. It is too wide at the top as it is an inch wide. But you can reduce that to 15/16ths by setting the depth so the groove it cuts is 15/ 16 inch wide.
The bottom has a ball bearing which you need to remove. I eyeballed it at about 3/8 inch. Can go back down to the basement, remove the bearing and s ee what the actual width is at the bottom. The cutting edges may work well at the bottom. But you can use a 3/8 straight router bit first and then u se the 45 degree bit. I think that will work to get what you want.
The router bits I have are from Harbor Freight, but the web site does not g ive good dimensions.
Could not find the router bit on ebay.
Dan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 21 Jul 2014 13:13:23 -0700 (PDT), rangerssuck


Do you have a milling machine or a milling attachment for your lathe? If so, then get some drill rod, turn the profile you want, transfer the part to your collet block, then mill the teeth in the part. Heat treat with a torch and then stone the teeth after the cutter has been hardened and tempered. If you can get by with just one cutting edge then mount your cutter blank in the lathe eccentrically. This can be done just by using a shim between one jaw and the blank in a three jaw chuck. Or use a 4 jaw chuck. Then mill the blank to get the one cutting edge. Then when the tool gets dull you only need to sharpen the top of the one tooth. The eccentricity of the tool will provide constant relief. You cound even make a one tooth cutter with the lathe and a bench grinder. Just use the grinder instead of the mill. I have made many custom cutters this way. Using the mill though, not the bench grinder. I have sharpened my custom cutters on the bench grinder though. It is pretty easy to make your own cutter this way and you can even cut steel if you harden the cutter properly. Just about two months ago I whipped out a special single flute cutter just the way I described above because the special one I ordered hadn't arrived yet and I needed to get the parts out the door. Eric
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Monday, July 21, 2014 4:13:23 PM UTC-4, rangerssuck wrote:

ake is a truncated V 15/16" wide at the top, 3/8" wide at the bottom and 1/ 4" deep. The dimensions aren't super critical, but closer is better.

rs. I also don't (as will become apparent) have more than a very little bit of experience grinding tool bits. I DO have 1x30 and 4x36 belt sanders, a set of 5C collets and a square collet block.

the line. Then grind the flat end and its cutting edges.

ot at all cheap and b) they have a half-inch shank and I have a 1/4" router . I'm not opposed to a new router, but only if I really need it.

blank? Even the most expensive spade bit is going to be less expensive than that router bit blank. Is there something about a spade bit that would mak e it totally unsuitable for this?

to do it? How much should I expect to pay?

Thanks for the input so far, and here are some answers to the questions tha t were raised: 1) The project is modifying the double-hung windows in my house to work wit h replacement jamb-liners. These are spring-loaded and are the mechanism fr om jeld-wen windows, purchased from an outfit in Milwaukee. They used to se ll a router bit for the purpose, but they say they can't get the blanks any more - what they were actually doing is modifying an HSS v-groove cutter th at has been discontinued by Sears. I had purchased a bit from them and it's done OK, but then I hit a nail and even though I've resharpened, it's not going to put up with that too many times and I have 25 more windows (50 mor e grooves) to do. The material I'm cutting is chestnut oak.
I have to do these windows one or two at a time, as the whole job is kind o f big and I don't want to disassemble all 25 windows at once.
I have a router table (shop made) set up to do this with the appropriate fe nces and feather boards, and I'd much rather not have to switch bits for ea ch cut. I imagine that two passes (3/8 straight) and a 45 v-groove with the bearing removed would probably do a great job, but it's either a bit chang e or a second machine. Also, having standard-size cutters (and carbide, too ) would be a major plus.
As for the spade bit being only a 1/4" shank, the router (and bit) that I h ave now is 1/4" shank, and that's not a problem.
What I would REALLY like is a shaper table to do this, but that's not in th e cards now, and would still involve either two passes or a custom cutter.
If I could come up with a way to do a quick-change of the bits (straight & V) that would get them to the same height (perhaps a small collar under one or the other if they're close to begin with the bit-switching wouldn't be so bad. If I have to adjust the height each time, it would be a bitch - my router table doesn't have a lift mechanism.
But back to the original question - is there anything inherently bad about using a modified spade bit in a router? Would it be likely to fly apart at speed if it was slightly off balance? [I've done some design work on contro ls for 90K RPM motors and seen some spectacular failures]
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Monday, July 21, 2014 4:13:23 PM UTC-4, rangerssuck wrote:


Since the grooves are straight with open ends you might consider making a molding plane, thus trading off an easier-to-make steel blade for a little woodworking. Dull circular saw blades can be annealed, cut up and rehardened. http://www.hyperkitten.com/tools/articles/Molding_Plane_Basics.php
-jsw
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tuesday, July 22, 2014 11:15:12 AM UTC-4, Jim Wilkins wrote:

rm

edge

I've seen those - The Woodright's shop is one of my all time favorites - bu t I have about 300 feet of this to do, and I'd like to get it done in my li fetime.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote in message

I've seen those - The Woodright's shop is one of my all time favorites - but I have about 300 feet of this to do, and I'd like to get it done in my lifetime.
You only have to plane what you can't remove with a straight router bit. -jsw
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 7/22/2014 11:21 AM, rangerssuck wrote:

You are not removing much material. With straight, flat material, a sharp plane, and a guide, I'd guess about it would take less than two minutes for an eight foot groove.
How about cutting a central dado, and two passes on a router table over a v groove bit to form the sides? Or form the sides with a tilted table saw blade?
Or a molding head for the table saw? Custom molding cutters are easier to shape than creating a router bit.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.