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I'd like to use a pattern bit to make a gun rack using the pattern in the picture.
If I use a 3/8 dia. pattern bit will I be have trouble with blowout on the end grain of the hooks? Inside radius of hooks is 3/4 inch and outside radius of hooks is 1/2 inch.
I plan on using red oak and the grain would run the length of the pattern.
Thanks
Jerry
Attachment 106590
If you cut the waste to within 1 mm of the line the bit will touch.. I'm guessing no. But..... I would certainly make an dummy and try first. It might prove that leaving the ends alone and finishing them by hand would be the best route.
Sarge..
Jerry -
I think you will be OK. Just do like Sarge said and cut the rough pattern close to the line.
Ted
If you use a pattern bit -- y'know, the kind with a bearing guide on the top or the bottom -- you may get chatter or chip-out as you cut across the end grain, because you must cut the whole thickness of the blank. Another approach would be to mount a template guide on the router. With this, you can make cutting passes at any depth of cut. Instead of needing to cut the full thickness of the blank, you could be cutting just an eighth or two. A plunge router makes it very easy to do this, but a non-plunge will do the trick too.
I would use a hand router and route backwards (climb cut) on the end grain.
I like all the responses so far.The design is such that you are "asking for" beakoffs. Have some CA glue around. The breakoouts should be easily put back on...and then go very carefully.
I really don't think you will have a problem at all if you do as suggested and cut down to a 1/16 from your pattern.
That can be done very easy on the bandsaw if you have one. This is what I use to cut down the wood before I take it to the router table.
http://www.rockler.com/product.cfm?p...nd%20saw%20pin
Right now they are really cheap. $4.
Then in the router table I use a Shear Flush trim bit, they are much better then a straight bit in my opinion.
http://pricecutter.com/down-shear-fl.../p/P12%2D1714/
Thanks for the advice folks. I kinda like Bills idea, didn't know either of those items existed...but that's why we ask at the Creek.:) Template guide sounded good too but I have a cheapy B&D plunge router without a way to mount a guide to it.
Quote:
Originally Posted by Jerry Bruette
You don't need a guide, just make a template out of some MDF and then double back tape it to the wood you are going to use.
Now use the guide on the bandsaw to cut it out. Then with the bearing on the end of the bit against the template you cut the wood to the exact size you want.
I recently had a problem with a pattern bit from Bosch. It was a 1/4" shank 1/2" diameter cutter with bearing mounted on top. The bushing that holds the bearing in place came loose and allowed the bearing to ride up on the shaft. I ended up gouging my template and ruining my workpiece.
The moral of the story is CHECK your bearings and stop collars often.
If you make a pattern out of MDF, hard surface the areas that the bearings will run on with a little epoxy and then resand. This will give you a hard smooth surface that the bearing will not sink into, something that will happen with MDF and soft woods. Just paint some on and it will sink in quite a ways and basically turn your pattern to plastic.
Don't use a 1/2" bit for that, go with the largest bit that you can swing with your router and is less radius than the curve you are cutting. You will get no tearout and a much better quality cut. I have pattern bits up to 1 1/2" bearing over from Whiteside, and they last forever, where a 1/2" bit will burn itself out quickly. In the end the cost is less. Ballew Saw has them in stock.
Another thought. Cut the stock on a bias so that the grain is never short at the bottom of the curve, or as an alternative when you are done with the cutting, drive a long screw through the back to strengthen the short grain area. Make the screw free through the wall side half so that it is pulling the "ears" rearward. Just insurance that you don't drop a $2000 Wetherby. :)
Oh ya. If you do go with a small bit, the advise to check the bearing every pass is spot on. The small bits tend to set up a vibration that loosens the collars. The big Whitesides have pressed on bearings, so no set screws to worry about, and the attendant unbalance condition it creates.
Opps... I had assumed you were going to use a template with that pattern bit. My bad.. as you should use a template IMO. I keep 1/2" MDF on hand as I do about two templates a week to use with pattern bits. I would make a template from MDF. Cut it out on the BS or jig-saw if you have a good one like Bosch.
Cut it basically to the line drawn out and then finish it off with files.. rasp and a spindle sander if you have one. You can't leave a ridge or rough spot in that template edge as Larry mentioned as it will tranfer to the actual stock. So.. you can use epoxy on small dips or sand it smooth with the spindle sand or files. But.. get it smooth as the bearing will transfer any discrepancy in the template to the stock
MDF if great for this. It's flat.. and if you screw up.. it's cheap. Once you have it done you draw out the pattern on the actual stock and then cut it on the BS to within about 1mm-2mm. Then attach the perfected template to the rough cut stock with double sided tape or if a side won't show... I use a short #8 screw counter sunk. In this case both sides will show so use the double tape.
Once the finished template is attached.. take it to the pattern bit to duplicate the cut on the good stuff.
Sarge..
I don't know if anyone has mentioned it but I only use a solid carbide up spiral these days for any router table pattern work. 1/2" or 1/4" double bottom bearing. Rarely have any blow out and the finish is great. Band saw within 1/16th and go for it. The rest is technique. I've made 50 candle holders for a fund raiser a couple of years ago. I used the 1/4" for all those parts. It's a sliding dovetail construction BTY.:)
I've had more than one of those Bosch pattern bits, and every one of them had the collar loose right out of the box. Be sure to tighten the grub screw, and they work quite well.Quote:
Originally Posted by Greg Coleman