Grizzly Drill Presses

[george wilson]

I noticed that the 20" drill press in Grizzly's Christmas flyer has a low speed of 210 rpm. The SMALLER drill presses go down to 140 rpm. Since the larger drill press SAYS it will drill a 1 1/4" hole in steel,and the smaller ones will drill a smaller maximum hole,which DO NOT require the drill to go as slow,why does the larger D.P. not go the slowest? It takes a very slow speed to drill large holes in steel.

I've been thinking about a heavier duty drill press,but find the speed difference very strange,and "upside down." Any comments? I am also a machinist.

[Dick Strauss]

1.5 hp on the 20" and 0.75 hp on the 15" DP...

[Tom Veatch]

If the difference in hole size capability is because of the power difference, I guess the question is, "Will a minimum value of 69.4 SFM (1.25" dia/212 RPM) do the job?"

[george wilson]

The drill press's power is not the issue. A large drill needs to go slower in steel,or the corners of the drill will just burn off.

I am also a machinist,and as toolmaker in the museum,I also made large wagon axles. We made them out of 2 1/2" square hot rolled steel. We had to drill large holes through the axles to mount them. I bought a large drill press from MSC for making them. It went slow enough,but It also cost about $2000.00,IIRC. It was an altogether heavier machine than the Grizzly here. the speeds,not the weight is the issue,however.

The maintenance dept. was wanting a large variable speed drill press,and was having the same problem finding one that ran decently slow. They weren't budgeted to spend a huge amount. It wouldn't COST any more for a designer to make a drill press run slower. Just different pulley diameters.

This seems to be a common problem today in metal lathes. They aren't designed to run NEARLY as show as you need them to,to turn work that is within their capacity. My lathe at work turned 11 RPM,which was good,for large work held in the gap,up to 2' in diameter. My lathe at home will hold 2' in the gap,but only went down to 60 RPM. I altered it to go half speed,or 30 RPM,but it still would be too fast for a large cast iron,or steel object. The turning tool would just burn right up because of the high circumferential speed of the object.

Same problem with large drill bits. Corners will tear right off.

I might add that that 20" Grizzly is a metal working type drill press,too. At least it has a metal working table on it,and a #4 MT spindle. You won't be able to use the sizes of drills that the #4MT will allow,though.I wonder if I could modify it to run slower? Perhaps it could accommodate a center pulley? I can't tell with the picture supplied.

Some of these designers apparently aren't machinists,or they'd know better.

[John Thompson]

I totally agree that the HP is not an issue. I also agree that an extremely slow speed is required to drill large holes in metal. You are a machinist and know that but.. I cannot answer the question of why a lower priced variable speed DP doesn't engineer the pullies to go as low as you need for metal but.. metal may be the key word here as most of the cheaper drill presses are designed for mainly WW'ing operations ( strickly speculating as I don't know for fact) which don't need a speed that low.

Perhaps "Papa Grizzly" could provide a better answer as to whether that particular press had serious metal workers in mind when designed?

Good luck...

[Mike Reinholtz]

I would love to know the answer to this as well, my father in law has been a machinist for a little more than 40 years and when helping me look for a new drill press has really stressed the need for something with a low rpm. Guess he knew I would be using it for metal as well as wood.

[george wilson]

The DP HAS A # MT spindle=metal working. Also,the "T" slot type table is for metal working. It should have better speeds for metal working. You CAN'T use the big drills that #4 MT spindle will accept on steel.

I wish Shiraz would get the manufacturers to make this DP correctly. It needs to run about 70 RPM at least. I would readily buy one if the speed range was correct. This IS NOT a variable speed DP,BTW.

[george wilson]

I wish Shiraz would join this discussion.

[Jason Beam]

It's less than a day old on a Sunday. He'll be along, I'm sure :)

[george wilson]

Sunday! I had forgotten that! I forget a lot since I am retired!! Really!!

[george wilson]

Bump to top.

[george wilson]

Any reply from Pappa Grizzly?

[Mike Reinholtz]

While searching online for DPs with a lower RPM range I found Rikon has a 20" model with 12 speeds ranging from 150-4200. I don't know much about Rikon (don't own any of their stuff) but it looks very similar to a couple other brands on the market. The one I was looking at is the 30-240, I found it online for $599.99.

[Rod Sheridan]

I've never had sucess drilling a 1.25" hole in steel with a belt drive drill press.

Every drill press I've used for that purpose has been a gear head type.

A 1.25" drill in mild steel would require 275 RPM to achieve 90 surface feet per minute drill speed.

Regards, Rod.

[george wilson]

I drill a smaller hole first,Rod. I had one at work that drilled bigger holes than that,belt driven. In fact,I drilled 1 1/2" holes through 2" steel plate to make a 50 ton press. First,though,a 1/2" hole,then a second larger one after that. I also want slower than 90 FPM.

[Ed Labadie]

I've got the 20" Grizz drill press. You will be dissapointed if you try to drill a 1 1/2 hole in steel.
The spindle pulley is held in place with a tapered fit, mine isn't machined accurately enough to keep the pulley from spinning under heavy load. The plastic nut that holds it on can't be tightened up enough to make any difference. The t-slots aren't machined either, and nothing standard fits. Be prepared to fit any t-nuts you may want to use.

Overall I'm not displeased with the machine. I really like the 20" capacity and the spindle runs true. Would I buy it again? Nope, I would go even bigger and heavier. :eek: Would I buy another Grizz? If I couldn't find a good used industrial machine, yes.

IMO, a company can rate a drill press for any size drill it wants, while it might have the hp to do it, usually there isn't enough mass to keep things from shaking and moving all over the place. Larger holes are best done on a mill or very large drill press that has substantional mass to handle the cutting forces reqiured.

Ed <-----25+ year machine designer

[george wilson]

Thanks,Ed. That is worthwhile info. It is too bad they make a 20" machine with no guts.

[Scott T Smith]

George - I'm with you on this. For years I've looked for a good quality drill press that would step down to extremely slow speeds for drilling large holes in steel. No luck.

I finally bit the bullet and bought a large variable speed Ellis. It's a fantastic drill press, but for $2,500 bucks that's the least that I would expect.

I have the 1 hp large radial arm Grizzly, but it only goes down to 200 rpm. I re-motored my last drill press in order to slow it down (from 3450 to 150).

You'd think that someone would offer a slow speed model for a reasonable price...